EP0781929A1 - Device for pumping or compressing a multi-phase fluid comprising tandem blading - Google Patents

Abstract

The pumping system comprises a hollow casing having an inlet orifice and a fluid outlet orifice. A rotor rotates inside the casing. The rotor comprises a hub with a blade (Gj) fixed to the hub. The blade has a first (A1j) and second (A2j) blades each having a leading edge (aij) and a trailing edge (fij). The angle making tangent to the curve of the outline leaving from the leading edge to one of the first or second blades relative to the peripheral or tangential direction of the system is between 0 and 45 degrees . The relative positioning of the different groups of blades is determined from a parameter chosen from four parameters. The tangential gap (h) relative to the pitch (t) expressed as the ratio h/t is between 0.60 and 0.8. The ratio of the axial overlap rj to the total chord CTj corresponding to a group of blades Gj is between -0.01 and 0.05. The chord ratio CFj/CRj) is between 0.5 and 1.5. The curvature ratio of the first blade to the second blade is between 0.1 and 1.0.

Description

The present invention relates to a device for compressing multiphase fluids which, before being compressed and under the pressure and temperature conditions considered, consist of a mixture in particular of a liquid phase and a gaseous phase which are not dissolved in the liquid, this liquid may or may not be saturated with gas.

The compression device or compression cell according to the invention is particularly well suited for pumping a multiphase fluid, for example, but not exclusively, a multiphase petroleum effluent composed of a mixture of water, oil and gas, and possibly solid particles. Pumping such an effluent poses problems which are all the more difficult to solve since, under the thermodynamic conditions in which the multiphase fluid is found before pumping, the value of the volumetric ratio of gas to liquid is greater.

It is recalled that the volumetric ratio of gas and liquid, hereinafter abbreviated as "volumetric ratio" or GLR from the English "Gas Liquid Ratio", is defined as the ratio of the volume of fluid in gaseous state to volume of fluid in the liquid state, the value of this ratio being in particular a function of the thermodynamic conditions of the multiphase fluid.

Whatever the design of the pumps used (reciprocating pumps, rotary pumps or trumpet pumps), good results are obtained when the value of the volumetric ratio of the fluid is very low or even zero, because the fluid then behaves like a single-phase fluid liquid. These materials are still usable when their operating conditions do not reveal phenomena capable of allowing the vaporization of a large part of the gas dissolved in the liquid, or when the value of the volumetric ratio at the inlet of the pump is at most equal to 0.2. Experience shows that beyond this value, the efficiency of these devices decreases very quickly.

To improve the functioning of existing devices, one solution consists in separating the liquid phase from the gas phase before pumping, and in treating the phases separately, in separate compression circuits respectively adapted to communicate a compression value to an essentially liquid phase. or to an essentially gaseous phase. The implementation of separate circuits is not always possible and often leads to more bulky, more expensive and more complex pumping systems.

This is why, we have tried to develop suitable pumping devices, not only to increase the total energy of the multiphase fluid, but capable of producing a multiphase fluid whose value of the volumetric ratio at the output of the pumping device is less than the value it has before pumping.

The prior art describes various blading profiles making it possible to obtain this result, in particular the applicant's patents FR-2,157,437, FR-2,333,139, FR-2,471,501 and FR-2,665,224, which specify profiles. blading or a geometry chosen for the fluid passage section delimited by two successive blades. In all cases, these profiles relate to simple blades, that is to say comprising only one piece unlike the blades, called "tandem blade", which comprise for the same group, at least two blades .

The performance of multiphase fluid pumping comprising so-called "simple" blades can be improved.

Thus, the prior art described, for example in the article "Optimization for Rotor Blades of Tandem Design for Axial Flow Compressors", published in the journal of Engineering for Power, Vol. 102, page 369 in April 1980, the use of compression devices comprising blades having tandem profiles.

However, the teaching of this prior art only relates to the compression of monophasic fluid, that is to say which, at the inlet of the compression device, essentially consist of a single phase, either liquid or gas. The geometrical characteristics of the tandem type blades described in this document are particularly well suited to the compression of a monophasic fluid whose behavior in compression cannot however be compared to the behavior of a fluid having several phases, for example fluids having at least one liquid phase and at least one gas phase, and therefore which are not suitable for pumping a multiphase fluid.

It has been discovered, and this is one of the objects of the present invention, that it is possible to improve the pumping of multiphase fluid by using tandem or "bladed in tandem" type blades having a geometrical configuration suitable for compressing a multiphase fluid comprising at least one liquid phase and at least one vapor or gas phase, the proportions of these two phases can vary over time.

As a reminder and in the rest of the description, the skeleton of a blade is defined as the surface at all points equidistant from the pressure side and suction side of this blade. So when we consider the intersection of a blade with a current surface of the flow of the fluid around this blade, a blade profile can be described by means of the geometric coordinates of the camber line and the law of distribution of the thickness of dawn along this line.

• A_ij : désigne une aube ayant le numéro i dans le groupe d'aubes j,
• a_ij : désigne le bord d'attaque d'une aube A_ij,
• f_ij : le bord de fuite d'une aube A_ij,
• G_j : se réfère au groupe d'aubes,
• C_Tj : corde totale d'un groupe d'aubes qui correspond à la corde définie à partir d'une pale ayant un profil équivalent au profil déterminé à partir de l'ensemble des aubes,
• C_Fj : corde de la première aube d'un groupe d'aubes,
• C_Rj : corde de la seconde aube d'un groupe d'aubes, pour des groupes d'aubes comportant deux aubes, mais qui pourrait sans sortir du cadre de l'invention être étendue à un nombre supérieur à 2,
• h le décalage tangentiel qui correspond à la distance (f_ij , a_ij ) projetée sur la direction périphérique (perpendiculaire à l'axe de rotation),
• α angle qui est défini sur des cylindres sensiblement coaxiaux de rayons constants dont l'axe est confondu avec l'axe de rotation de la machine. Sur ces surfaces, α est l'angle que fait la direction périphérique (perpendiculaire à l'axe de rotation) et la tangente en un point quelconque à la courbe tracée par le squelette tel que défini précédemment.

In the following description, the following references will be used:

• A _ij : designates a blade with the number i in the group of blades j,
• a _ij : designates the leading edge of a blade A _ij ,
• f _ij : the trailing edge of a blade A _ij ,
• G _j : refers to the group of blades,
• C _Tj : total chord of a group of blades which corresponds to the chord defined from a blade having a profile equivalent to the profile determined from all the blades,
• C _Fj : chord of the first blade of a group of blades,
• C _Rj : chord of the second blade of a group of blades, for groups of blades comprising two blades, but which could without going beyond the scope of the invention be extended to a number greater than 2,
• h the tangential offset which corresponds to the distance (f _ij , a _ij ) projected onto the peripheral direction (perpendicular to the axis of rotation),
• α angle which is defined on substantially coaxial cylinders of constant radii whose axis coincides with the axis of rotation of the machine. On these surfaces, α is the angle made by the peripheral direction (perpendicular to the axis of rotation) and the tangent at any point on the curve drawn by the skeleton as defined above.

To obtain the aforementioned improvement, the device according to the present invention uses tandem blades, comprising blades formed by one or more profiles or blades.

For example, when the blade or group of blades G _j has two blades A _1j and A _2j , the first blade, called for example the main blade, is the one which sees the fluid in flow, or the particle of fluid, the first, and the second blade is called, for example, auxiliary blade.

The particular geometrical characteristics of each of these blades, as well as their arrangement with respect to each other, make it possible to optimize the compression of a multiphase fluid and to remix at least part of the liquid phase coming from a first group of blades with at least part of the gas phase coming from the preceding group of blades. We thus promotes the meeting of at least part of the gaseous phase which flows near the upper surface and at least part of the liquid phase which circulates on the side of the lower surface.

The different blades forming a blade can be completely separated from each other or even derive from a blade in which are arranged orifices, or passage openings, each of the parts separated by these orifices being able to be assimilated to a blade.

Thus, the present invention relates to a device for compressing or pumping a multiphase fluid comprising at least one gaseous phase and at least one liquid phase, the device comprising a hollow casing having an inlet orifice and at least one orifice evacuation of said multiphase fluid, at least one rotor which can rotate inside said casing along an axis of rotation Ox, said rotor consisting of a hub and at least one blade integral with this hub, said blade comprises a first blade At _1d and a second dawn At _2d .

It is characterized in that said blade G _j comprises a first blade A _1j and a second blade A _2j , each of the blades having a leading edge a _ij and a trailing edge f _ij , the angle α made by the tangent to the curve of the skeleton, said angle being counted from the leading edge a _ij of at least one of said first and / or second blade relative to the peripheral or tangential direction of the device is between 0 and 45 °.

As a reminder and in the following description, the skeleton of a blade is defined as the surface at all points equivalent to the pressure side and suction side of this blade. When we consider the intersection of a vane with a current flow surface around this vane, we can describe a vane profile using the geometric coordinates of the line of curvature and the distribution law the blade thickness along this line.

The present invention also relates to a device comprising for example at least one impeller comprising two blades or group of blades G ₁ , G ₂ each comprising a first blade A _1j and a second blade A _2j .

• paramètre 1 : le décalage tangentiel h rapporté au pas t, exprimé sous la forme du rapport h/t, où t est le pas correspondant à la distance entre les deux bords de fuite f₂₁ et f₂₂ correspondant aux secondes aubes A₂₁ et A₂₂ de chacun des groupes d'aubes G₁ et G₂, la valeur du paramètre 1 est compris dans l'intervalle [0,95 ; 1,05],
• paramètre 2 : le rapport du recouvrement axial r_j et de la corde totale C_Tj correspondant à un groupe d'aubes G_j qui est compris dans l'intervalle de valeurs [0,0 ; 0,15],
• paramètre 3 : le rapport de corde R_Cj = (C_Fj / C_Rj) défini pour un groupe d'aubage G_j par le rapport de la valeur de la corde C_Fj de la première aube à la valeur de la corde de la seconde aube C_Rj pour un des groupes d'aubage compris entre [0,5 ; 1,5],
• paramètre 4 : le rapport de cambrure Φ_j défini par la valeur de la cambrure Φ_Fj de la première aube à la valeur de la cambrure Φ_Rj de la seconde aube d'un même groupe d'aubage, compris entre [0,5 ; 1].

It is characterized in that the geometrical characteristics of the first and / or of the second blade of each of the groups of blades G _j and the positioning of the different groups of blades with respect to each other are determined as a function at least one parameter chosen from the following four parameters:

• parameter 1: the tangential offset h related to the pitch t, expressed in the form of the ratio h / t, where t is the pitch corresponding to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the second blades A ₂₁ and A ₂₂ of each of the groups of blades G ₁ and G ₂ , the value of the parameter 1 is included in the interval [0.95; 1.05],
• parameter 2: the ratio of the axial overlap r _j and the total chord C _Tj corresponding to a group of blades G _j which is included in the range of values [0,0; 0.15],
• parameter 3: the chord ratio R _Cj = (C _Fj / C _Rj ) defined for a vane group G _j by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second vane C _Rj for one of the vane groups between [0.5; 1.5],
• parameter 4: the camber ratio Φ _j defined by the value of the camber Φ _Fj of the first blade to the value of the camber Φ _Rj of the second blade of the same blade group, between [0.5; 1].

• paramètre 1 : le décalage tangentiel h rapporté au pas t, exprimé sous la forme du rapport h/t, où t est le pas correspondant à la distance entre les deux bords de fuite f₂₁ et f₂₂ correspondant aux secondes aubes A₂₁ et A₂₂ de chacun des groupes d'aubes G₁ et G₂, la valeur du paramètre 1 est compris dans l'intervalle [0,60 ; 0,80],
• paramètre 2 : le rapport du recouvrement axial r_j et de la corde totale C_Tj correspondant à un groupe d'aubes G_j qui est compris dans l'intervalle de valeurs [-0,01; 0,05],
• paramètre 3 : le rapport de corde R_Cj = (C_Fj / C_Rj) défini pour un groupe d'aubage G_j par le rapport de la valeur de la corde C_Fj de la première aube à la valeur de la corde de la seconde aube C_Rj pour un des groupes d'aubage compris entre [0,5 ; 1,5],
• paramètre 4 : le rapport de cambrure Φ_j défini par la valeur de la cambrure Φ_Fj de la première aube à la valeur de la cambrure Φ_Rj de la seconde aube d'un même groupe d'aubage, compris entre [0,10 ; 1].

The device comprises at least one rectifier comprising two blades or group of blades G ₁ , G ₂ each comprising a first blade A _1j and a second blade A _2j . It is characterized in that the geometrical characteristics of the first and / or of the second blade of each of the groups of blades G _j and the positioning of the different groups of blades with respect to each other are determined as a function at least one parameter chosen from the following four parameters:

• parameter 1: the tangential offset h related to the pitch t, expressed in the form of the ratio h / t, where t is the pitch corresponding to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the second blades A ₂₁ and A ₂₂ of each of the groups of blades G ₁ and G ₂ , the value of the parameter 1 is included in the interval [0.60; 0.80],
• parameter 2: the ratio of the axial overlap r _j and the total chord C _Tj corresponding to a group of blades G _j which is included in the range of values [-0.01; 0.05],
• parameter 3: the chord ratio R _Cj = (C _Fj / C _Rj ) defined for a vane group G _j by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second vane C _Rj for one of the vane groups between [0.5; 1.5],
• parameter 4: the camber ratio Φ _j defined by the value of the camber Φ _Fj of the first blade to the value of the camber Φ _Rj of the second blade of the same blade group, between [0.10; 1].

The device comprises for example a rectifier and / or an impeller comprising at least two groups of blades G ₁ , G ₂ each comprising a first blade (A ₁₁ , A ₁₂ ) and a second blade (A ₂₁ , A ₂₂ ), the geometrical characteristics of said first and second blades of each of the groups of blades and the positioning of the different groups of blades relative to one another are for example determined as a function of three of the parameters given in claims 2 and / or 3, parameter 1, parameter 2 and parameter 3, each of these parameters belonging to the intervals cited above.

The geometric characteristics of at least one impeller and / or at least one rectifier of the compression device are for example specified using the fourth parameter, the value of the camber ratio Φ _j being chosen in combination with the three values of the parameters of claims 2 and / or 3.

The maximum thickness ratio of the first and second blades e1 / e2 is for example between 0.5 and 1, for an impeller and / or a rectifier.

The thickness e1 of the first blade is between 2 and 10 mm and / or the thickness e2 of the second blade is between 2 and 20 mm.

A blade is for example connected to a previous blade and / or a next blade using a mechanical element.

The device comprises for example at least one rectifier and at least one impeller, the impeller is for example disposed before the impeller when we consider the direction of flow of the fluid.

The device comprises for example at least one impeller and at least two rectifiers, the impeller being for example disposed between the two rectifiers.

The invention also relates to a device for compressing or pumping a multiphase fluid comprising at least one gaseous phase and at least one liquid phase, the device comprising a hollow casing having an inlet port and an outlet port for said fluid multiphase, at least one rotor able to rotate inside said casing along an axis of rotation Ox, said rotor consisting of a hub and at least one blade integral with this hub, said blade comprising a first face or upper surfaces and a second face designated lower surface.

The device for compressing or pumping a multiphase fluid is characterized in that said blade is provided over at least part of its length with one or more openings making it possible to put the two said lower and upper surfaces in communication, in order to favor the meeting of at least part of the gaseous phase flowing near the upper surface and at least part of the liquid phase flowing on the side of the lower surface.

The invention also relates to a multiphase pump intended for example for pumping effluents of the multiphase petroleum type. It is characterized in that it comprises at least one impeller and at least one rectifier which has one of the geometric characteristics, for example previously mentioned.

It also applies to the definition of a multiphase pump intended for pumping multiphase petroleum effluent, comprising for example a liquid phase, a gas phase and possibly a solid phase in the form of particles.

• elle permet de minimiser la séparation des phases liquide et gaz contenues dans l'effluent en favorisant au moins en partie leur remélange de phases,
• les pertes d'énergie hydraulique sont minimisées car :
  • * l'aubage est mieux adapté à l'incidence de l'écoulement entrant dans le dispositif de compression,
  • * le taux de décélération du fluide, élevé dans le cas de cambrures d'aubage fortes et ayant notamment pour conséquence d'augmenter les pertes hydrauliques et les risques de décollement de l'écoulement, s'en trouve minimisé, et
• au niveau du stator, la structure tandem des pales améliore le guidage du fluide et permet ainsi d'égaliser les vitesses des filets fluides dans la section de sortie.

Compared to devices comprising so-called "simple" blades, the tandem type structure applied in particular to the field of pumping multiphase fluid, such as an oil effluent, in an optimized configuration defined above, gives the compression device the following advantages:

• it makes it possible to minimize the separation of the liquid and gas phases contained in the effluent by at least partially promoting their remixing of phases,
• hydraulic energy losses are minimized because:
  • * the blading is better adapted to the incidence of the flow entering the compression device,
  • * the rate of deceleration of the fluid, high in the case of strong blade camber and having in particular the consequence of increasing the hydraulic losses and the risks of flow delamination, is minimized, and
• at the level of the stator, the tandem structure of the blades improves the guidance of the fluid and thus makes it possible to equalize the speeds of the fluid threads in the outlet section.

• les figures 1 et 1A représentent schématiquement et en coupe axiale, un mode particulier de réalisation du dispositif selon l'invention pour le pompage, d'un effluent polyphasique,
• la figure 2 montre un impulseur ou roue mobile, vu en perspective,
• la figure 3 est une figure développée de la trace résultant de l'intersection des pales avec une surface cylindrique de rayon fixe, montrant les paramètres de définition d'une géométrie aubages tandem selon l'invention,
• la figure 4 schématise le mélange des flux de la phase gazeuse et de la phase liquide
• la figure 5 schématise un exemple de dispositif selon l'invention pour lequel les différents groupes d'aubes sont reliées par un moyen mécanique, et
• la figure 6 est un exemple de réalisation simpliste d'aubages selon l'invention pourvus de lumières permettant d'optimiser le mélange des phases.

Other advantages and characteristics of the invention will appear better on reading the description given below by way of exemplary embodiments, in the context of in no way limiting applications, in the compression or pumping of a multiphase effluent of petroleum type, comprising at least one liquid phase, one gaseous phase and possibly a solid phase, with reference to the attached drawings in which:

• FIGS. 1 and 1A show schematically and in axial section, a particular embodiment of the device according to the invention for pumping, a multiphase effluent,
• FIG. 2 shows an impeller or mobile wheel, seen in perspective,
• FIG. 3 is a developed figure of the trace resulting from the intersection of the blades with a cylindrical surface of fixed radius, showing the parameters for defining a tandem blade geometry according to the invention,
• Figure 4 shows schematically the mixture of gas phase and liquid phase flows
• FIG. 5 shows diagrammatically an example of a device according to the invention for which the different groups of blades are connected by mechanical means, and
• Figure 6 is a simplistic embodiment of blades according to the invention provided with lights to optimize the mixing of phases.

In what follows, the term "fluid" will denote a multiphase fluid comprising in particular a liquid phase and a gaseous phase, and optionally a solid phase which may be in the form of solid particles, for example sand or viscous particles such hydrate agglomerates. The liquid phase can in particular consist of liquids having different natures, just as the gas phase can consist of gases of different nature.

The fluid comprises phases of different natures inside and outside the compression device, unlike monophasic fluids which can undergo transformations inside the device.

Figures 1 and 1A show schematically and in axial section a particular, non-limiting, embodiment of the device according to the invention provided for pumping a multiphase petroleum effluent.

The pumping device comprises a hollow casing 1, which is for example cylindrical to be easily introduced into a well, for non-limiting applications of the device according to the invention relating to the pumping of effluents into a production well. The casing 1 is provided with at least one orifice 2 for admitting the multiphase fluid and at least one discharge orifice 3, which communicates with the flow circuit of the pumped fluid. This circuit is shown diagrammatically by a pipe or pipe 4 at the end of which the casing 1 is fixed by any suitable means known to those skilled in the art, for example a thread referenced 5 in the figure.

In the example illustrated by FIG. 1A, the intake orifice 2 is in the form of openings made in the wall of the casing 1, and the pumping device comprises at these orifices a deflector 14 integral with the casing 1 for deflect the fluid after it has entered the casing and impart to it a speed having a substantially axial direction, that is to say substantially parallel to the axis of rotation of the pump.

Inside the casing 1 is placed a rotor comprising a shaft 6 driven in rotation by motor means 7 (FIG. 1), such as for example, but not exclusively, an electric motor, and possibly a transmission member, shown schematically in 8 (FIG. 1) making it possible in particular to adapt the speed of rotation of the motor shaft to the speed of rotation at which the shaft 6 must be driven.

The shaft 6 is for example held in position by at least two separate bearings 9 and 10, for example described in the applicant's patent FR-2,471,501.

.The bearing 10 is made integral with the casing 1 by radial arms 11, so that the spaces between these radial arms allow the fluid to flow in the direction indicated by the arrow $\overrightarrow{\text{F}}$

.

Details concerning the mounting of the bearings 9 and 10 are given explicitly in patent FR 2,471,501, in particular the arrangements for obtaining sealing between the various parts of the device and are moreover sufficiently known to those skilled in the art not to be described in more detail below.

Between the intake 2 and discharge 3 orifices of the pumping device and inside the casing 1, is placed at least one element or stage adapted to increase the total energy of the fluid.

In Figure 1, there are shown three elements having the function of increasing the energy of the fluid, referenced 17, 18 and 19. This number is not limiting and depends on the increase in pressure which it is desired to obtain. . These elements are referred to below as impellers.

These elements described below in detail in FIG. 3 are integral with the shaft 6 on which they are, for example, force fitted, the spacing between the elements being ensured by spacers 20 to 23.

Preferably, the device also includes one or more rectifying elements. For example, a rectifier (24, 25, 26) is placed at the outlet of each pressurizing element (17, 18, 19), each rectifier being secured to the casing 1, for example, by means of fixing screws 27 .

The presence of rectifiers is not necessary for the implementation of the device according to the invention. Nevertheless, it offers a non-negligible advantage because it makes it possible to guide the fluid or effluent through the different stages of the compression device.

It is understood that the clearances between the pressurizing elements and the casing and the clearances between the pressurizing elements and the rectifiers are reduced in a manner known by a person skilled in the art to their minimum value compatible with the operation of the pump.

FIG. 2 represents, in perspective view, a nonlimiting example of embodiment of a pressurizing element or impeller stage essentially comprising a hub 28 integral with the shaft 6 which, during the operation of the device, is driven in rotation in the direction indicated by the arrow R. This hub 28 comprises at least one blade 30 composed of two blades 30a and 30b, hereinafter called first blade or main blade and second blade or auxiliary blade, whose geometrical characteristics and positioning are one with respect to the other are given in relation to FIG. 3. The number of blades 29, 30 is in no way limiting and given by way of example only. In general, this number is chosen to facilitate the static and dynamic balancing of the rotor. The height of the blades is such that the shape which they define during their rotation is complementary to the bore which, in this embodiment, is cylindrical.

The effective profile of a tandem blade or a group of blades corresponding to the profile that the blade would have if it were made up of a single part, may be substantially identical to one of the profiles described in patents FR-2,157,437, FR-2,333,139, FR-2,471,501 and FR-2,665,224 of the applicant, the latter defining the profile of a blade from the section variation of an orthoradial channel defined by two successive blades. The profile of a tandem blade comprising a first blade 30a and a second blade 30b can in fact be assimilated to an effective profile taking into account the profiles of each of the blades. It is also possible to define an orthoradial channel as the channel delimited by two effective blades or group of blades.

Likewise, each blade of a tandem blade can be chosen according to one of the profiles described in these patents.

The number of tandem blades, that is to say groups of blades arranged in tandem with respect to each other, is always preferably greater than 2.

Without departing from the scope of the present invention, this number of blades can be between 3 and 8, and preferably between 4 and 6, in particular for impellers whose outside diameter of the blades is large, for example between 200 and 400mm.

To ensure and optimize the compression of a multiphase fluid, the blades forming a blade or a group of blades and the arrangement of the blades and / or blades relative to each other inside the compression device have characteristics determined geometries, for example using at least one of the parameters given in FIG. 3.

In the example described in FIG. 3, each group of blades G _j comprises, for example two blades A _1j and A _2j arranged one after the other, but could without departing from the scope of the invention be extended to groups of blades with a number of blades greater than 2.

The groups of blades are designated in FIG. 3, respectively by G ₁ and G ₂ . Each of the groups includes a first dawn A _1j or main dawn and a second dawn A _2j or auxiliary dawn.

A representation to describe a blade in a simple way, is to define its geometric layout on the developed surface of the cylindrical envelope at the outside radius.

correspond au sens de l'écoulement du fluide polyphasique entrant dans le dispositif de compression.In FIG. 3, the axis of rotation is represented by the line m, and the line p corresponds to the peripheral or tangential direction of the compression device. The arrow $\overrightarrow{\text{E}}$

corresponds to the direction of flow of the multiphase fluid entering the compression device.

Generally, a vane A _ij has a leading edge referenced in the figure "a _ij " and a trailing edge "f _ij ", where i is the number of a vane A _ij inside the group d 'vanes indexed j.

Thus a group of blades G _j is associated with a first blade labeled A _1j and a second blade labeled A _2j , for example, A ₁₁ corresponds to the first blade of the first blade group G ₁ and A ₂₁ corresponds to the second dawn of this same group of blades.

The chord is defined for a blade as the distance between its leading edge a _ij and its trailing edge f _ij . It is marked on the right m respectively by C _Fj for the first dawn A _1j and C _Rj for the second dawn A _2j .

It is also possible to define the total chord length C _Tj for a group of blades G _j , identified on the right m by the projection of the distance separating the leading edge a ₁₁ from the first blade, and the edge of leakage f ₂₁ of the second blade for the same group of blades G _j .

The characteristics of the compression device are determined, for example, from at least one parameter chosen from a set of characteristic parameters, specific to the blades and to the position of the groups of blades. The choice thus makes it possible to delimit an optimal operating range for the compression device.

• le décalage tangentiel h, correspondant à la distance entre le bord d'attaque a₂₁ de la seconde aube A₂₁ du premier groupe d'aube G₁, et le bord de fuite f₁₂ de la première aube A₁₂ du second groupe d'aube G₂. La valeur de ce paramètre est par exemple exprimée en fonction du pas t, et donné sous la forme d'un rapport h/t. Le pas t correspond à la distance entre les deux bords de fuite f₂₁ et f₂₂ correspondant aux aubes auxiliaires A₂₁ et A₂₂ des premiers et second groupes d'aubes G₁ et G₂,
• le recouvrement axial "r_j" repéré par rapport à la direction m et qui correspond au recouvrement de la première aube A_1j du groupe d'aubes G_j et de la seconde aube A_2j du même groupe d'aubes G_j, avantageusement on définit la valeur relative de recouvrement "r_j" rapportée à la corde C_Fj de la première aube d'un groupe d'aubes,
• le rapport de corde R_Cj = (C_Fj / C_Rj) défini, par exemple, par le rapport de la valeur de la corde C_Fj de la première aube à la valeur de la corde de la seconde aube C_Rj, pour le groupe d'aubes G_j.

The set of parameters, from which these characteristics are selected, includes for example, at least the following three parameters:

• the tangential offset h, corresponding to the distance between the leading edge a ₂₁ of the second blade A ₂₁ of the first group of blades G ₁ , and the trailing edge f ₁₂ of the first blade A ₁₂ of the second group of dawn G ₂ . The value of this parameter is for example expressed as a function of the step t, and given in the form of an h / t ratio. The pitch t corresponds to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the auxiliary blades A ₂₁ and A ₂₂ of the first and second groups of blades G ₁ and G ₂ ,
• the axial overlap "r _j " identified with respect to the direction m and which corresponds to the overlap of the first blade A _1j of the group of blades G _j and of the second blade A _2j of the same group of blades G _j , advantageously we defines the relative recovery value "r _j " referred to the chord C _Fj of the first blade of a group of blades,
• the chord ratio R _Cj = (C _Fj / C _Rj ) defined, for example, by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second dawn C _Rj , for the group vanes G _j .

By an appropriate choice of the values of at least one of the three parameters previously defined, it is possible to obtain an optimized compression device.

According to a preferred embodiment for the pumping or compression device according to the invention, the values of at least one of the three parameters previously defined are chosen.

• * le décalage tangentiel h rapporté au pas t est compris dans l'intervalle [0,95; 1,05],
• * le rapport r_j/C_Tj appartient à l'intervalle [0,0 ; 0,15],
• * le rapport de corde R_Cj est compris entre [0,5 ; 1,5 ]

To define an impeller, the value of at least one of the three parameters is preferably chosen in the intervals given below:

• * the tangential offset h related to the step t is included in the interval [0.95; 1.05],
• * the ratio r _j / C _Tj belongs to the interval [0,0; 0.15],
• * the chord ratio R _Cj is between [0.5; 1.5]

This defines a geometry for the blades and an arrangement of at least two groups of blades, for an impeller, in order to obtain optimal operation of the device for compressing a multiphase fluid.

Advantageously, the three parameters are chosen from the three intervals previously given and a fourth parameter chosen in combination with the first three is associated with them to optimize the compression operation. This fourth parameter is, for example the camber ratio Φ _j determined for a group of blades and defined as the ratio of the value of the camber Φ _Fj of the first blade A _1j to the value of the camber Φ _Rj of the second dawn A _2d for a given group of dawn.

The value of this parameter is preferably chosen in the range [0.5; 1].

• * le décalage tangentiel h rapporté au pas t est compris dans l'intervalle [0,60; 0,80],
• * le rapport r_j/C_Tj appartient à l'intervalle [-0,01 ; 0,05],
• * le rapport de corde R_Cj est compris entre [0,5; 1,5 ]

Identically, a rectifier is defined for example by choosing these characteristics in the following way:

• * the tangential shift h related to the step t is included in the interval [0.60; 0.80],
• * the ratio r _j / C _Tj belongs to the interval [-0.01; 0.05],
• * the chord ratio R _Cj is between [0.5; 1.5]

This defines a geometry for the blades and an arrangement of at least two groups of blades, at the level of the rectifiers, making it possible to obtain preferential operation of the device for compressing a multiphase fluid.

In this case, the camber ratio Φ _j determined for a group of vanes of a rectifier, and defined as the ratio of the value of the camber Φ _Fj of the first blade A _1j to the value of the camber Φ _Rj of the second blade A _2j for a given group of blades, is preferably chosen from the interval [0.10; 1].

According to a preferred embodiment, the following three parameters are selected to produce the impellers and / or for the rectifiers: the tangential offset h relative to the pitch t, the ratio r _j / C _Tj and the chord ratio R _Cj . This defines a field of pumping or compression devices adapted to communicate to a multiphase type fluid, for example an oil effluent, a compression value sufficient to ensure its transfer from a production location for example a source or a well. production to a place of destination, such as a processing platform or an intermediate place, without having to separate the phases.

A section offered for the flow of the fluid in an impeller and / or a rectifier is for example defined by the total area of passage of the fluid in a plane Pi perpendicular to the axis of rotation of the device and located between the inlet and the device output. The total area evolves for example according to a substantially constant law and bounded by a minimum area value and a maximum value, chosen so that the ratio of two areas chosen for two planes Pi as defined above is preferably included in the interval [2.2; 0.45].

As a result, in particular, according to an optimized embodiment, the impellers have a passage area for the fluid in question in their outlet plane limited according to the value of the corresponding area in their inlet plane.

According to one embodiment of the device, the ratio of maximum thicknesses of the first and of the second vane e1 / e2, is preferably chosen in the interval [0.6; 1] for an impeller and preferably chosen in the range [0.5; 1] for a rectifier.

According to a preferred embodiment, the geometric characteristics of the groups of blades for the movable or impeller wheels are defined for example by values chosen so that the ratio of the outside diameter of the wheel expressed in mm, to the number of blades belongs to the interval [40; 60].

According to a particular embodiment for which only the impellers have one of the characteristics of the invention as described above, it is possible to use a rectifier of any type, known to a person skilled in the art, and which can in particular have characteristics adapted to the characteristics of the impeller stage.

At the output of an impeller stage, the multiphase fluid is driven by a speed having at least one axial component and one circumferential component. As is well known to specialists, the use of a rectifier increases the static pressure by eliminating or at least reducing the circumferential components of the flow speed of the fluid.

It is possible to produce the pumping or compression device according to the invention, to comply for example with the provisions of the various elements, for example the impellers and the rectifiers, given for example in one of the applicant's patents FR 2,333,139 , FR 2,471,501, or FR 2,665,224.

Thus a multi-stage pumping or compression device is formed for example by a succession of several compression stages formed for example by a movable wheel (impeller) preceded or succeeded by a fixed wheel (rectifier), according to the direction of flow of the fluid . The passage section offered to the fluid is for example substantially continuous and the flow of the fluid takes place in a preferred direction aligned with the axis of rotation of the device.

In order to better understand the phenomena acting during the pumping of a multiphase fluid in a compression device comprising tandem blades, FIG. 4 illustrates the different flows of the different phases, liquid and gaseous in a pumping or compression device, in particular during their flow in a channel delimited by two tandem blades.

Thus in FIG. 4, there is shown in a diagram identical to that of FIG. 3, two groups of blades G ₁ and G ₂ and dashed lines corresponding to the groups of blades G ₀ and G ₃ arranged on one side and the other of the two groups previously defined.

In this way, several fluid flow channels are identified, E ₀ , E ₁ , E ₂ located respectively between the groups of blades G ₀ and G ₁ , G ₁ and G ₂ , G ₂ and G ₃ .

To each of the blades, there is associated a reference I _ij designating the pressure side of the blade and E _ij the suction side of the blade.

For each group of blades, a flow passage is defined between the lower surface I _1j of the first blade and the upper surface E _2j of the second blade, for example.

Thus, in FIG. 4, the passage p ₁ corresponds to the flow passage located between the two blades A ₁₁ , A ₁₂ of the first group of blades and p ₂ the flow passage located between the blades A ₁₂ , A ₂₂ of the second group of blades, the flow passages each having a width the value of which is fixed by the positioning of the two blades within the same group of blades.

This flow channel makes it possible to remix at least part of the liquid phase coming from a flow channel with, at least, part of the gaseous phase circulating in an adjacent flow channel.

Indeed, during its passage through a pressurizing element, and under the effect of the rotation, a separation of the phases composing the multiphase fluid is observed, in particular the separation of the liquid phase and the gaseous phase, referenced respectively l _k and g _k , with k index associated with the channel in which the fluid circulates (E ₀ , E ₁ , E ₂ ).

Under the effect of a transverse pressure gradient, the liquid phase l _k is entrained towards the face of the blade under overpressure, the lower surface of the blade while the gas phase g _k will on the contrary migrate towards the face in dawn depression or upper surface. This phenomenon is also seen in compression devices comprising blades called simple blades.

par exemple.According to the diagram shown in FIG. 4, the multiphase fluid to which it is desired to communicate a certain energy value circulates between two groups of successive tandem blades, for example the flow channel E ₁ and according to the arrow $\overrightarrow{\text{E}}$

for example.

Inside this channel, the fluid decomposes into a liquid fraction l ₁ which migrates towards the lower surface side I ₁₁ of the vane A ₁₁ and a gaseous fraction g ₁ which is attracted towards the upper surface side E ₂₁ of the first blade A ₁₂ of the second group of blades.

The liquid fraction I ₁ attracted by the pressure side I ₁₁ flows through the flow passage p ₁ and also opens into the flow channel E ₀ , continues to circulate until it mixes with at least part of the gas fraction g ₀ coming from the separation of the liquid and gas phases in the flow channel E ₀ .

The gas g ₀ and liquid I1 phases by re-mixing, make it possible to at least partially compensate for the phenomenon of segregation of the liquid and gas phases which appears during the pumping of a multiphase fluid and which contributes to the reduction in efficiency for pumping.

This phenomenon is reproduced at the level of each of the flow passages and therefore at the level of each group of blades, the gaseous and liquid fluids, coming for example from adjacent channels are remixed.

Advantageously, the presence of a flow passage between two blades of a group of blades appreciably improves the efficiency of the compression devices in comparison with the efficiency obtained with a blade formed of a single blade with substantially identical surface and equivalent geometry. .

The dimension of the flow passage is for example chosen from the set of parameters previously defined.

FIG. 5 is a perspective view of a group of blades which are for example connected to each other by at least one mechanical element 40. Thus a first blade is for example connected to at least the following blade (taking the meaning flow) and / or at a previous dawn. This mechanical element 40 can be positioned anywhere along and / or across the width of a blade and can take any geometric shape which respects the flow of the fluid, that is to say which does not disturb fluid flow.

Advantageously, the presence of at least one mechanical element makes it possible to maintain the distance between the blades, and to make the specific arrangement of the blades respect each other. It thus plays the role of mechanical reinforcement of the device.

Figure 6 shows schematically an alternative embodiment of the device according to the invention for which a group of blades is obtained from a blade provided with one or more orifices distributed over at least part of its length. The parts of the blade separated by these orifices thus form "sub-blades" which each have a function substantially identical to the function fulfilled by the blades A _ij described in FIG. 3.

The lights or orifices distributed along the blade 50 thus allow the passage of the liquid and gaseous fractions circulating respectively near the pressure side of the blade and the suction side of the blade and coming from adjacent channels, for example as it is depicted in Figure 3.

In Figure 6, there is shown a shape which can be taken by a gas pocket or a liquid pocket.

The liquid fraction tends to pass through at least one of the openings 51 to mix with the gaseous fraction flowing on the upper side and thus form a multiphase mixture. In this way, the value of the GLR ratio is notably reduced, due to the enrichment of the gas fraction with a liquid part and the compression of the multiphase fluid is improved, by compensating for the separation originating from the step of compression of the multiphase fluid. as described above in relation to FIG. 4.

The orifices or mixing lights may have different geometries and selected dimensions, in particular depending on the nature of the phases constituting the fluid to facilitate the passage of these phases towards one another.

Claims (12)

Device for compressing or pumping a multiphase fluid comprising at least one liquid phase and at least one gaseous phase, the device comprising at least one hollow casing (1) having at least one inlet orifice (2) and at least one evacuation orifice (3) of said fluid, at least one rotor capable of rotating inside this casing, along an axis of rotation Ox, said rotor consisting of a hub (28) and at least one blade G _j integral with this hub, characterized in that said blade G _j comprises a first blade A _1j and a second blade A _2j , each of the blades having a leading edge a _ij and a trailing edge f _ij , the angle α that does the tangent to the curve of the skeleton, said angle being counted from the leading edge a _ij of at least one of said first and / or second blade relative to the peripheral or tangential direction of the device is between 0 and 45 °. Device according to claim characterized in that it comprises at least one impeller comprising two blades or group of blades G ₁ , G ₂ each comprising a first blade A _1j and a second blade A _2j , and characterized in that the geometric characteristics of the first and / or second blade of each of the groups of blades G _j and the positioning of the different groups of blades with respect to each other are determined as a function of at least one parameter chosen from the following four parameters: • parameter 1: the tangential offset h related to the pitch t, expressed in the form of the ratio h / t, where t is the pitch corresponding to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the second blades A ₂₁ and At ₂₂ of each of the groups of blades G ₁ and G ₂ , the value of parameter 1 is included in the interval [0.95; 1.05], • parameter 2: the ratio of the axial overlap r _j and the total chord C _Tj corresponding to a group of blades G _j which is included in the range of values [0,0; 0.15], • parameter 3: the chord ratio R _Cj = (C _Fj / C _Rj ) defined for a vane group G _j by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second blade C _Rj for one of the vane groups between [0.5; 1.5], • parameter 4: the camber ratio Φ _j defined by the value of the camber Φ _Fj of the first blade to the value of the camber Φ _Rj of the second blade of the same blade group, between [0.5 ; 1]. Device according to claim 1, characterized in that it comprises at least one rectifier comprising two blades or group of blades G ₁ , G ₂ each comprising a first blade A _1j and a second blade A _2j , and characterized in that the geometric characteristics of the first and / or second blade of each of the groups of blades G _j and the positioning of the different groups of blades with respect to each other are determined as a function of at least one chosen parameter among the following four parameters: • parameter 1: the tangential offset h related to the pitch t, expressed in the form of the ratio h / t, where t is the pitch corresponding to the distance between the two trailing edges f ₂₁ and f ₂₂ corresponding to the second blades A ₂₁ and At ₂₂ of each of the groups of blades G ₁ and G ₂ , the value of parameter 1 is included in the interval [0.60; 0.80], • parameter 2: the ratio of the axial overlap r _j and the total chord C _Tj corresponding to a group of blades G _j which is included in the range of values [-0.01; 0.05], • parameter 3: the chord ratio R _Cj = (C _Fj / C _Rj ) defined for a vane group G _j by the ratio of the value of the chord C _Fj of the first dawn to the value of the chord of the second blade C _Rj for one of the vane groups between [0.5; 1.5], • parameter 4: the camber ratio Φ _j defined by the value of the camber Φ _Fj of the first vane to the value of the camber Φ _Rj of the second vane of the same blade group, between [0.10 ; 1]. Device according to one of claims 1 to 3, characterized in that a rectifier and / or an impeller comprise at least two groups of blades G ₁ , G ₂ each comprising a first blade (A ₁₁ , A ₁₂ ) and a second blade (A ₂₁ , A ₂₂ ), and characterized in that the geometric characteristics of said first and second blades of each of the groups of blades and the positioning of the different groups of blades relative to each other are determined as a function of three of the parameters given in claims 2 and / or 3, parameter 1, parameter 2 and parameter 3, each of these parameters belonging to the intervals given in claims 2 and / or 3. Device according to one of Claims 2 to 4, characterized in that the geometric characteristics of at least one impeller and / or at least one rectifier of the compression device are specified using the fourth parameter, the value of camber ratio Φ _j being chosen in combination with the three values of the parameters of claims 2 and / or 3. Device according to one of claims 1 to 5, characterized in that the maximum thickness ratio of the first and second blades e1 / e2 is between 0.5 and 1, for an impeller and / or a rectifier. Device according to claim 6, characterized in that the thickness el of the first blade is between 2 and 10 mm and / or the thickness e2 of the second blade is between 2 and 20 mm. Device according to one of the preceding claims, characterized in that a blade is connected to a previous and / or next blade by means of a mechanical element (40). Device according to one of claims 2 to 8, characterized in that it comprises at least one rectifier and at least one impeller, said impeller being disposed before the impeller in the direction of flow of the fluid. Device according to one of claims 2 to 8, characterized in that it comprises at least one impeller and at least two rectifiers, said impeller being disposed between the two rectifiers. Device for compressing or pumping a multiphase fluid comprising at least one gaseous phase and at least one liquid phase, the device comprising a hollow casing having an inlet port and an outlet port for said multiphase fluid, at least one rotor being able to rotate inside said casing along an axis of rotation Ox, said rotor consisting of a hub and at least one blade integral with this hub, said blade comprising a first face or upper surface and a second face designated intrados, characterized in that said blade (50) is provided over at least part of its length with one or more openings (51) making it possible to put the two said lower and upper surfaces in communication, in order to promote the meeting of at least one part of the gas phase flowing near the upper surface and at least part of the liquid phase flowing on the side of the lower surface. Multi-phase pump intended for pumping multi-phase effluent, characterized in that it comprises at least one impeller and or one rectifier having one of the characteristics of the preceding claims.

Images