CN106247407A - A kind of fuel support plate ejector filler - Google Patents

Abstract

The invention discloses a fuel support plate injector. The fuel of a scramjet engine and a combined cycle power engine is used as a coolant. The coolant flows in a cooling channel to cool the support plate, and is sprayed into a combustion chamber to be mixed with gas. Combustion, realize the normal work of the support plate for a long time. The front edge of the support plate is a rounded wedge-shaped structure, and the flow channel is located inside the front edge of the support plate; there are multiple sets of channel inlets on the inside of the front part of the support plate and the inside of the rear wall of the support plate, and there are multiple sets of fuel injection holes on the side wall of the support plate. Located at the bottom of the support plate and connected with the flow channel and the cooling channel, the coolant enters the entrance of the channel, flows along the channel to the bottom of the support plate and collects in the liquid collection chamber, and is sprayed out of the support plate through the fuel injection hole; the coolant is sprayed into the combustion chamber Previously, the flow heat exchange method of forced convection absorbs heat inside the channel, reduces the temperature of the support plate and realizes fuel preheating at the same time. The strut injector has a simple structure, has good heat protection effect on the strut, and can realize the function of injecting fuel to the strut.

Description

fuel injector

technical field

The invention relates to the fields of scramjet engines and combined cycle power engines, in particular to a fuel branch injector with a cooling structure.

Background technique

Engine combustion efficiency is closely related to the mixing effect of fuel and air; in order to increase the injection depth of fuel in the high-speed incoming flow, the injected fuel can be more evenly distributed in the mainstream gas of the combustion chamber, and the Mixing efficiency of air, usually using fuel rail injectors. However, the strut plate injector bears extremely high heat load in the engine, especially the front edge of the strut plate, which is very easy to be burned during operation. For the thermal protection of the support plate, the conventional method is to use high-temperature-resistant metal materials and use the material heat sink for passive thermal protection, but the thermal environment of the support plate is extremely harsh, and the temperature at the front edge of the support plate in the scramjet engine can reach about 3000K, exceeding The use limit of most existing metal materials, the support plate using the metal heat sink cannot realize long-term normal work.

The traditional support plates that use high-temperature-resistant materials for passive thermal protection are expensive, and it is currently difficult to find materials that can withstand high temperatures, high heat flow, and thermal environments in the engine for a long time; patent 200910236121. "structure", using the low-temperature gas ejected from the slit at the front edge of the support plate to form a low-temperature gas film on the surface of the support plate to protect the support plate from heat, but the structure of the support plate is relatively complicated and the processing technology is difficult; in the patent 201310561173.6, a A "thermal protection method for injection struts of scram engines by sweating and impingement cooling", according to the characteristics of porous media, using fuel as a coolant, combined with the concept of impingement cooling, to achieve the thermal protection effect on injection struts. However, the structure of the support plate is complex, and the porous structure is easy to generate large flow resistance, which has high requirements on the fuel supply system, which is not conducive to fuel injection and blending combustion.

As a key component of the scramjet engine and combined cycle power engine, the strut plate plays an important role in fuel injection, mixing and combustion. Plate heat protection is the key point in engine heat protection.

Contents of the invention

In order to avoid the deficiencies in the prior art, the present invention proposes a fuel branch injector; the injector uses the fuel of a scramjet engine and a combined cycle power engine as a coolant, and adopts a regenerative cooling method. The cooling channel is reasonably designed for the heating conditions in the flow field. The coolant is in the cooling channel through forced convection heat exchange to realize the active thermal protection of the injector of the support plate, and then sprayed into the combustion chamber and mixed with the gas for combustion to realize the length of the support plate. Time works fine.

The technical solution adopted by the present invention to solve its technical problems is: the fuel branch injector comprises a branch, and a cooling passage is arranged on the inner side of the wall near the branch, and it is characterized in that the branch is a front edge rounded wedge-shaped structure, and the flow passage Located inside the front wall of the support plate, the distance between the front edge of the flow channel and the front edge of the outer wall of the support plate is 1.0-3.0mm, the front edge of the flow channel is rounded, and the rounding radius is 0.5-2.0mm; the inner side of the front edge wall of the support plate and the rear wall of the support plate There are multiple sets of cooling channel inlets on the inner side, and multiple sets of fuel injection holes on the side wall of the support plate. The liquid collection cavity is located at the bottom of the support plate, and the liquid collection cavity is connected with the flow channel. The liquid collection cavity is connected, the coolant enters the channel entrance, flows along the channel to the bottom of the support plate, collects in the liquid collection cavity, and is sprayed out of the support plate through the fuel injection hole; before the coolant is injected into the combustion chamber, it exchanges heat by forced convection flow The method absorbs heat inside the channel, reduces the temperature of the support plate and realizes fuel preheating at the same time.

The cross-sectional shape of the cooling channel in the support plate is rectangular or circular; the distance between the wall of the cooling channel and the wall of the support plate is 0.5-3.0 mm.

The cross-sectional shape of the flow channel in the support plate is a rounded triangle structure with a front edge, which is the same as the shape of the front part of the cross-section of the support plate.

The support plate material is stainless steel or high temperature alloy steel with high thermal conductivity.

Beneficial effect

The invention proposes a fuel branch injector, which uses the fuel of a scramjet engine and a combined cycle power engine as a coolant, and adopts a regenerative cooling method. The cooling channel is designed, and the coolant actively cools the support plate by means of convective heat exchange during the flow in the cooling channel, and then sprays into the combustion chamber and mixes and burns with the gas to realize the long-term normal operation of the support plate. The strut injector has a simple structure, is easy to process, has a good heat protection effect on the strut, and can realize the function of injecting fuel to the strut.

The fuel support plate injector of the present invention is equipped with a cooling channel inside, which can provide active thermal protection for the support plate, avoid the erosion of high-temperature gas, and at the same time make the injected fuel more uniformly mixed and distributed in the mainstream gas of the combustion chamber. The structure of the support plate injector is mainly composed of the outer wall of the support plate, the support plate, the cooling channel and the liquid collection chamber. When the support plate works in the high-temperature gas environment in the engine flow channel, the coolant enters the cooling channel inside the support plate from the inlet of the cooling channel, and absorbs the heat transferred from the high-temperature gas inside the combustion chamber to the outer wall of the support plate through convective heat exchange, making the support plate solid The temperature of the area is maintained below the allowable temperature of the metal material used. The coolant is mixed in the liquid collection chamber at the bottom of the support plate, so that the overall temperature of the mixed coolant is uniform, and then injected into the combustion chamber through the fuel injection hole to mix and burn with the incoming flow.

According to the principle of gas-solid-liquid coupling heat transfer, the fuel branch injector of the present invention rationally designs and arranges cooling channels inside the metal support plate according to the heat distribution of the support plate. By adjusting the configuration of the cooling channel, the setting of the cooling channel, The cross-sectional area of the cooling channel and the flow rate of the coolant realize effective regenerative cooling of the support plate.

The invention adopts the engine fuel as the coolant to carry out thermal protection on the metal material support plate, avoiding the severe ablation, short working time, difficult processing, high cost and insufficient structural strength of the metal material support plate adopting passive thermal protection. Defects, regenerative cooling of the support plate is realized.

Description of drawings

A fuel branch injector of the present invention will be further described in detail below with reference to the drawings and embodiments.

Fig. 1 is a schematic structural view of the fuel branch injector of the present invention.

Fig. 2 is a schematic view of the inlet of the cooling channel of the fuel branch injector of the present invention.

Fig. 3 is a cross-sectional view of the branch plate of the fuel branch injector of the present invention.

Figure 4 is a graph showing the average temperature of the coolant at the front edge of the strut and at the outlet of the cooling channel when the coolant flow rate of a single strut is constant.

Fig. 5 is the distribution curve of the temperature along the height direction of the strut plate on the center line of the wall surface of the front edge of the strut plate under the corresponding coolant flow rate.

in the picture

1. Cooling channel 2. Liquid collection chamber 3. Support plate 4. Front edge wall of support plate 5. Side wall of support plate 6. Back wall of support plate 7. Bottom of support plate 8. Channel inlet 9. Flow channel 10. Fuel injection hole

detailed description

This embodiment is a fuel branch injector.

Referring to Fig. 1 to Fig. 5, the fuel branch injector of this embodiment uses the fuel of the scramjet engine and the combined cycle power engine as the coolant, and adopts the regenerative cooling method; the coolant flows in the cooling channel to cool the branch plate , sprayed into the combustion chamber and mixed with gas for combustion, so that the support plate can work normally for a long time.

The fuel branch injector in this embodiment includes a cooling channel 1, a liquid collection chamber 2, a support plate 3, a front edge wall surface 4 of the support plate, a side wall surface 5 of the support plate, a rear wall surface 6 of the support plate, a bottom portion of the support plate 7, and a passage inlet 8 , the flow channel 9, the fuel injection hole 10, and the cooling channel is arranged on the inner side of the wall surface close to the support plate; wherein, the support plate 3 is a rounded wedge-shaped structure at the front edge, and the flow channel 9 is arranged on the inner side of the wall surface 4 of the front edge of the support plate, and the front edge of the flow channel 9 The distance from the front edge of the outer wall of the support plate is 1.0 mm to 3.0 mm, and the front edge of the flow channel 9 is rounded with a radius of 0.5 mm to 2.0 mm. There are three sets of coolant passage inlets 8 on the inner side of the front edge wall surface 4 of the support plate and the inner side of the rear wall surface 6 of the support plate, and three sets of fuel injection holes 10 are respectively provided on the side wall surface 5 of the support plate; The channels 9 are connected and communicated, and the cooling channels 1 near the inner wall of the support plate are all communicated with the liquid collecting cavity. The coolant enters the channel inlet 8, flows along the channel to the bottom of the support plate 7, collects and mixes in the liquid collection chamber 2, so that the temperature of the coolant is relatively uniform, and is sprayed out through the fuel injection hole 10, and injected into the combustion chamber to mix with the mainstream gas combustion. Before the coolant is sprayed into the combustion chamber, it absorbs heat inside the channel by means of forced convection flow heat exchange, reducing the temperature of the support plate and realizing fuel preheating at the same time. The cross-sectional shape of the cooling channel 1 is a rectangular or circular structure; the distance between the wall of the cooling channel and the wall of the support plate is 0.5-3.0 mm. The cross-sectional shape of the flow channel 9 is a rounded triangle structure at the front edge, and the cross-sectional shape of the flow channel 9 is the same as that of the front part of the cross-section of the support plate 3 . The support plate material is stainless steel or high temperature alloy steel with high thermal conductivity. The position of the strut plate with high temperature and large heat flow during the engine working process is the stagnation point of the air flow at the front edge of the strut plate. During the working process, the flow rate of the coolant, namely aviation kerosene, is reasonably distributed according to the cross-sectional area of the cooling channel and the heating condition of the strut plate.

In this embodiment, according to the shape of the support plate, the thermal environment and heat distribution characteristics of the support plate, the allowable temperature and strength requirements of the material of the support plate, and the heat absorption capacity of the coolant, the shape of the cooling channel of the support plate, the cross-sectional area of the cooling channel, and the cooling agent are determined. Flow distribution and coolant velocity multiparameters; used to illustrate the effectiveness of the cooling design, a numerical simulation of the active cooling of the struts was carried out. When the incoming air flow is 6Ma, the total gas temperature in the engine is 3000K. Figure 4 shows that the stainless steel support plate uses kerosene as the coolant for active cooling. The coolant flow rate is 15g/s, 20g/s, 30g/s, 50g/s The average oil temperature line diagram of the front edge of the support plate and the outlet of the cooling channel of the support plate. Fig. 5 is the distribution curve of the temperature along the height direction of the strut plate on the center line of the wall surface of the front edge of the strut plate under the corresponding coolant flow rate. It can be seen from the figure that the surface temperature of the support plate is kept below the normal working temperature range of the stainless steel material for a long time, and the front edge of the support plate is the gas stagnation point, that is, the highest temperature point. The results show that the fuel branch injector can work stably for a long time. The temperature curve in Fig. 4 shows that the centerline temperature of the front wall of the support plate decreases with the increase of the coolant flow rate, and the heat transfer is enhanced at the bottom of the support plate, and the wall temperature is lower, while the temperature of the front wall near the bottom surface of the support plate is exchanged. The thermal efficiency decreases and the temperature is higher, but the wall temperature at the front edge of the support plate is lower than 1000K in the whole range, indicating that the cooling is effective and the support plate can work for a long time. According to the gas-solid-liquid coupling heat transfer mechanism, a cooling channel is arranged inside the support plate, and the engine fuel is used as the active coolant of the support plate. The temperature of the plate is maintained within the range allowed by the material, and the fuel is preheated at the same time, so that fuel injection can be realized while realizing effective cooling of the support plate.

Claims (4)

1. a fuel support plate ejector filler, including support plate, is laying cooling duct inside support plate wall, it is characterised in that: Described support plate is leading edge rounding wedge structure, and flow channel is positioned at inside support plate leading edge wall, flow channel leading edge distance support plate Outer wall leading edge distance is 1.0～3.0mm, flow channel leading edge rounding, and chamfering radius is 0.5～2.0mm；In support plate leading edge wall There is many group cooling ducts entrance inside side and support plate rear surface respectively, support plate sidewall is organized fuel jet orifice, liquid collecting cavity respectively Being positioned at bottom support plate, liquid collecting cavity is connected with flow channel, and the cooling duct at support plate side wall surface all connects with liquid collecting cavity, Coolant enters feeder connection, collects in liquid collecting cavity along passage to support plate flows, sprays support plate by propellant spray hole；Cold But agent is before spraying into combustor, absorbs heat in channel interior in the fluid interchange mode of forced convertion, reduces a plate temperature simultaneously Realize fuel preheating.

Fuel support plate ejector filler the most according to claim 1, it is characterised in that: described support plate inner cooling channel cross section shape Shape is rectangle or circle；Cooling duct wall and support plate wall distance are 0.5～3.0mm.

Fuel support plate ejector filler the most according to claim 1, it is characterised in that: flow channel cross shape in described support plate Shape is leading edge rounded triangular structure, and identical with support plate cross section front shape.

Fuel support plate ejector filler the most according to claim 1, it is characterised in that: described panel material is high thermal conductivity coefficient Rustless steel or high-temperature alloy steel.