CN118817117A - A TDLAS high temperature and high pressure calibration system - Google Patents

Abstract

The invention discloses a TDLAS high-temperature high-pressure calibration system, which comprises a high-pressure chamber, a high-pressure control module, a high-temperature tube furnace, a temperature control and display module and a measuring light path, wherein the high-pressure chamber comprises a left end cover flange and a right end cover flange which are respectively used for sealing two ends of the high-pressure chamber, and the high-pressure control module is used for providing target gas with preset pressure and uniformly filling the target gas into a measuring area in the center of a furnace tube; the high-temperature tube furnace is arranged in the high-pressure chamber and comprises a furnace tube, a heating wire, a temperature control thermocouple and a temperature thermocouple; the temperature control and display module is used for PID temperature control of the high-temperature tube furnace and displaying the temperature of the center of the furnace tube; the measuring light path is positioned on the central axis of the furnace tube and comprises a first light guide column, a measuring area and a second light guide column, and the measuring area is positioned between the first light guide column and the second light guide column. The invention enables all parts bearing high temperature and high pressure to be completely independent, overcomes the limitation of high temperature yield strength of materials, and can realize the calibration of the TDLAS sensor under high temperature and high pressure environment.

Description

A TDLAS high temperature and high pressure calibration system

Technical Field

The invention belongs to the technical field of gas temperature testing based on absorption spectroscopy, and in particular relates to a TDLAS (Tunable Diode Laser Absorption Spectroscopy) high temperature and high pressure calibration system.

Background Art

Laser absorption spectroscopy technology uses laser as the excitation light source and obtains measurement information by sensing the electromagnetic field related to the internal energy distribution and energy level transition of the measured object. It has the advantages of non-contact, fast response, and easy to achieve two-dimensional field reconstruction. It is especially suitable for flow field measurement of aircraft engine combustion parameters that change rapidly. However, for the high temperature and high pressure environment commonly used in engines and industrial field applications, there is a common problem of inconsistent measurement and calibration environment. That is, TDLAS temperature sensors are usually calibrated under laboratory normal pressure and high temperature conditions. Under the actual high pressure environment, the absorption spectrum line shape changes significantly due to the impact of collision broadening, resulting in a large deviation in the final measurement result. A more representative research work abroad is the TDLAS high temperature and high pressure calibration device built by the Hanson team of Stanford University. It uses a combination of a tubular furnace and a high temperature and high pressure gas chamber. However, the main body of the high pressure gas chamber is subjected to both high temperature and high pressure. Limited by the high temperature yield strength of its own material, it can only reach 700K and 3MPa, which cannot meet the high temperature and high pressure calibration requirements of TDLAS sensors for engine and industrial field testing.

Summary of the invention

The purpose of the present invention is to provide a TDLAS high temperature and high pressure calibration system, which makes all components subjected to high temperature and high pressure completely independent, overcomes the limitation of high temperature yield strength of materials, and can realize the calibration of TDLAS sensors under high temperature (1000°C) and high pressure (3MPa) environment.

One aspect of the present invention provides a TDLAS high-temperature and high-pressure calibration system, comprising: a high-pressure chamber, a high-pressure control module, a high-temperature tube furnace, a temperature control and display module, and a measuring optical path; the high-pressure chamber comprises a left end cover flange and a right end cover flange respectively used to seal the two ends of the high-pressure chamber, a high-pressure air inlet interface is welded to the upper end of the high-pressure chamber, and is connected by a stainless steel ferrule joint, the high-pressure control module is used to provide a target gas of a predetermined pressure and evenly fill it into the measuring area at the center of the furnace tube; the high-temperature tube furnace is placed inside the high-pressure chamber, the high-temperature tube furnace comprises a furnace tube, a heating wire, a temperature-controlling thermocouple, and a temperature-measuring thermocouple, the heating wire is wound around the surface of the furnace tube, the temperature-controlling thermocouple is connected to the temperature-measuring thermocouple ... The thermocouple is used to perform PID temperature control feedback on the high-temperature tube furnace, and the temperature measuring thermocouple is arranged in the center of the furnace tube for monitoring the temperature of the center of the furnace tube; a power supply and a thermocouple interface are welded on the upper end of the high-pressure chamber for connecting the heating wire, the temperature control thermocouple, the temperature measuring thermocouple and the temperature control and display module, and the temperature control and display module is used to perform PID temperature control on the high-temperature tube furnace and display the temperature of the center of the furnace tube; the measuring optical path is located on the central axis of the furnace tube, including a first light guide column, a measuring area, and a second light guide column, the measuring area is located between the first light guide column and the second light guide column, and the first light guide column and the second light guide column are fixedly mounted on the left end cover flange and the right end cover flange respectively.

Preferably, the measuring optical path also includes a collimator, a left end cover quartz window and a right end cover quartz window, the collimator is fixedly mounted on the left side of the left end cover sealing flange, and the left end cover quartz window and the right end cover quartz window are respectively mounted at the center of the left end cover flange and the right end cover flange.

Preferably, the high-pressure chamber also includes three water-cooling jackets, which are the first water-cooling jacket, the second water-cooling jacket and the third water-cooling jacket from left to right. Annular water-cooling jackets are respectively arranged in the center of the left end cover flange and the right end cover flange for cooling the left and right end cover flanges, the left and right end cover quartz windows, and the first and second light guide columns.

Preferably, the main body of the high-pressure chamber is cylindrical and made of stainless steel, and the three water-cooling jackets are stainless steel cylinders.

Preferably, the high-pressure control module includes a high-pressure gas cylinder, a pressure controller, an atomizer, and a heating pipe. The high-pressure gas cylinder is used to fill high-pressure gas, the pressure controller is used to control the pressure value of the gas to a predetermined value, the atomizer is used to atomize distilled water into water vapor, and the heating pipe is used to heat the gas.

Preferably, the high-pressure gas cylinder, pressure controller, atomizer, and heating pipe are connected by metal pipes and sealed by stainless steel ferrule joints.

Preferably, the high-temperature tube furnace also includes an insulation layer wrapped around the outer layer of the furnace tube. The high-temperature tube furnace is a three-stage tube furnace, the heating wire is three-stage temperature controlled, and three temperature-controlled thermocouples are evenly distributed between the heating wire and the insulation layer for PID temperature feedback of the high-temperature tube furnace.

Preferably, the temperature control and display module includes a support plate, a touch display screen, and a control circuit board. The support plate is used to support the high-pressure chamber and the built-in high-temperature tube furnace; the heating wire, the temperature-controlling thermocouple and the temperature-measuring thermocouple are connected to the control circuit board via a power supply and a thermocouple interface, and the touch display screen is used for real-time temperature display and temperature control parameter setting.

According to the TDLAS high temperature and high pressure calibration system of the above aspects of the present invention, a high temperature tube furnace is built into the high pressure chamber, so that all components subjected to high temperature and high pressure are completely independent, thus overcoming the limitation of the high temperature yield strength of the material, and realizing the calibration of the TDLAS sensor in a high temperature (1000°C) and high pressure (3MPa) environment.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

FIG1 is a schematic structural diagram of a TDLAS high temperature and high pressure calibration system according to an embodiment of the present invention;

FIG2 is a schematic structural diagram of a high-voltage control module according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the structure of a temperature control and display module according to an embodiment of the present invention.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

An embodiment of the present invention provides a TDLAS high temperature and high pressure calibration system. The TDLAS high temperature and high pressure calibration system of the embodiment of the present invention includes a high pressure chamber, a high pressure control module 14, a high temperature tube furnace, a temperature control and display module 10, and a measurement optical path.

FIG1 is a schematic diagram of the structure of a TDLAS high temperature and high pressure calibration system according to an embodiment of the present invention. As shown in FIG1 , the main body of the high pressure chamber is cylindrical in design and made of stainless steel. The main body of the high pressure chamber is water-cooled in three sections, from left to right, in order of the first water cooling jacket 9, the second water cooling jacket 12 and the third water cooling jacket 15. The three water cooling jackets are, for example, stainless steel cylinders with a wall thickness of 3 mm, each of which is welded with a Φ6 mm quick-plug interface at the top and bottom. The cooling water is introduced in accordance with the principle of "in from the bottom and out from the top", and the first water cooling jacket outlet 8, the second water cooling jacket outlet 11, and the third water cooling jacket outlet 16 are arranged in sequence at the upper end of the high pressure chamber. The high pressure chamber includes a left end cover flange 1 and a right end cover flange 17, which are respectively used to seal the two ends of the high pressure chamber. A left end cover quartz window 4 is installed in the center of the left end cover flange 1 for passing through the measurement light path, and is sealed by the left end cover sealing flange 3 and the left end cover rubber sealing ring 5. The center of the left end cover flange 1 is provided with a left end cover annular water cooling jacket 7, which is used for cooling the left end cover flange 1, the left end cover quartz window 4, the left end cover rubber sealing ring 5, and the first light guide column 30, and is also used for installing and fixing the first light guide column 30. The left end cover flange 1 is arranged with the left end cover water cooling jacket water inlet 2 and the left end cover water cooling jacket water outlet 6 in sequence from top to bottom, and the cooling water is introduced in the order of "bottom in and top out". The left and right end covers of the high pressure cabin are arranged symmetrically, and the water cooling and sealing installation refer to the left end design, including the right end cover sealing flange 19, the right end cover rubber sealing ring 21, the left end cover annular water cooling jacket 23, the right end cover water cooling jacket water inlet 22 and the right end cover water cooling jacket water outlet 18.

The high-temperature tube furnace is used to provide a uniform and stable constant temperature zone for the system, and the high-temperature tube furnace is placed inside the high-pressure chamber. In the embodiment shown in Figure 1, the high-temperature tube furnace includes a furnace tube 24, a heating wire 25, a temperature-controlling thermocouple 29, and a temperature-measuring thermocouple 31. The high-pressure chamber has a built-in three-stage tube furnace, which is heated by a heating wire 25. The heating wire 25 is directly wound around the surface of the furnace tube 24. The heating wire 25 is, for example, a nickel-chromium 2080 heating wire. The furnace tube 24 is made of alumina material, for example, with a length of 50 cm, an inner diameter of 4 cm, and a wall thickness of 0.5 cm. The upper limit of the long-term use temperature is 1700°C. The thermal insulation layer 27 uses high-temperature resistant aluminum silicate insulation cotton, which is wrapped around the outer layer of the furnace tube 24, for example, with a thickness of 1 cm and a temperature resistance of 1700°C. The heating wire 25 is three-stage temperature controlled. Three temperature control thermocouples 29 are evenly distributed between the heating wire 25 and the insulation layer 27, which are used for PID (proportional-integral-differential) temperature feedback of the tubular furnace. A temperature measuring thermocouple 31 is arranged in the center of the furnace tube 24. The temperature control thermocouple 29 and the temperature measuring thermocouple 31 are connected to the temperature control and display module 10 through the power supply and thermocouple interface. The upper end of the high-pressure chamber is welded with a power supply and a thermocouple interface, which is used to connect the heating wire 25, the temperature control thermocouple 29 and the temperature control and display module 10. The interface is sealed with epoxy resin glue. The effective heating zone length of the furnace body is 50cm, the central constant temperature zone length is 10cmm, the temperature uniformity is ≤2℃/10cm, and the power is 1.5kW.

In this embodiment, the TDLAS measurement optical path is located on the central axis of the furnace tube, including a collimator, a left end cap quartz window 4, a first light guide column 30, a measurement area 28, a second light guide column 26, and a right end cap quartz window 20. The laser emitted by the laser is collimated by the collimator, and the collimator is fixed on the left side of the left end cap sealing flange 3. The laser passes through the left end cap quartz window 4, the first light guide column 30, the measurement area 28, the second light guide column 26, and the right end cap quartz window 20 in sequence and is received by the detector. In addition, the collimator is installed as close to the left end cap quartz window 4 as possible, and the detector photosensitive surface is installed as close to the right end cap quartz window 20 as possible, or it is purged with dry high-purity nitrogen to avoid air interference with the measurement of target gases such as water vapor or _CO2 . The first light guide column 30 and the second light guide column 26 mainly function to isolate the low-temperature zones on both sides of the tubular furnace. In one embodiment, the first light guide column 30 and the second light guide column 26 are made of single crystal sapphire, with a spectral transmission range of 0.17 μm to 5.5 μm, a length of 20 cm, a diameter of 2.5 cm, optical polishing of both end faces and a 10° wedge angle to avoid interference effects of optical standards, and a long-term operating temperature of 1800°C.

A high-pressure air inlet interface is welded on the upper end of the high-pressure chamber, which is connected to the high-pressure control module 14 through a stainless steel ferrule joint, and is connected in series with a digital pressure gauge and a safety valve 13. The high-pressure control module 14 is used to provide a high-pressure environment for the system. As shown in FIG2 , the high-pressure control module 14 includes a high-pressure gas cylinder 141, a pressure control valve 142, a pressure controller 143, an atomizer 144, and a heating pipe 145. The components are connected by metal pipes and sealed by stainless steel ferrule joints.

During the TDLAS high temperature and high pressure calibration with _H2O as the target gas, high purity nitrogen is filled into the high pressure gas cylinder 141, distilled water is first added into the atomizer 144, the heating function of the atomizer 144 is turned on, and the temperature is kept above 110°C; then the heating function of the heating pipe 145 is turned on, and the temperature is kept above 110°C to ensure that the internal water vapor does not condense; after the target gas is introduced into the high temperature and high pressure calibration device for 10 minutes before sealing, after the target gas evenly fills the measuring area 28, the sealing flange 17 is sealed, the pressure value is controlled to a predetermined value by the pressure controller 143, the water vapor is carried into the measuring area 28 by the high purity nitrogen, and the TDLAS temperature sensor calibration is performed after the temperature and pressure are stabilized.

When _CO2 is used as the target gas, the high-pressure gas cylinder 141 is filled with the corresponding standard gas, the heating function of the atomizer 144 is turned off, and then the heating function of the heating pipe 145 is turned on, and the temperature is maintained above 110°C; after the target gas is introduced into the high-temperature and high-pressure calibration device for 10 minutes before sealing, after the target gas evenly fills the measuring area 28, the sealing flange 17 is sealed, and the pressure controller 143 controls the pressure value to a predetermined value, and the TDLAS temperature sensor is calibrated after the temperature and pressure stabilize.

The temperature control and display module 10 is used for high-pressure chamber support and tube furnace temperature control and display. The temperature control and display module 10 in this embodiment is shown in Figure 3. The temperature control and display module includes a support plate, a touch display screen 102, a control circuit board 106, a switch, etc., which mainly realizes the PID temperature control of the furnace tube of the high-temperature tube furnace and the temperature display function of the center measurement area of the furnace tube. In one embodiment, the support plate includes a left support plate 101 and a right support plate 103, which are made of 2mm thick stainless steel to support the high-pressure chamber and its built-in tube furnace; the heating wire 25, the temperature control thermocouple 29 and the temperature control couple 31 are connected to the control circuit board 106 through the power supply and thermocouple interface through the wire, and are controlled by the control circuit board 106. The power supply and thermocouple interface are sealed with flanges and poured epoxy resin glue; the touch display screen 102 is used for real-time temperature display and temperature control parameter setting; the switch includes a power switch 104 and a heating switch 105.

The working process of the TDLAS high temperature and high pressure calibration system is as follows: first turn on the power switch 104, then set the temperature value by touching the display screen 102, and then turn on the heating switch 105. When the displayed temperature reaches the set temperature, turn on the pressure control module 10 and adjust it to the target pressure value. After the temperature and pressure are stable for 10 minutes, the TDLAS sensor calibration can be carried out.

To sum up, the TDLAS high temperature and high pressure calibration system of the embodiment of the present invention includes a high pressure system and a high temperature system. The overall architecture is a tubular furnace built in a high pressure chamber. The advantage is that all components subjected to high temperature and high pressure are completely independent, that is, components subjected to high pressure do not withstand high temperature, and components subjected to high temperature do not withstand high pressure, thereby ensuring safe, stable and reliable operation of the equipment.

Compared with the prior art, the TDLAS high temperature and high pressure calibration system of the embodiment of the present invention has the following beneficial effects:

(1) The present invention adopts a high-temperature tubular furnace structure built into a high-pressure chamber, so that all components subjected to high temperature and high pressure are completely independent, overcoming the limitation of the high-temperature yield strength of the material, and realizing the calibration of the TDLAS sensor under high temperature (1000°C) and high pressure (3MPa) environment.

(2) The present invention can calibrate a TDLAS sensor whose target gas is H ₂ O, CO ₂ or other gases under high temperature and high pressure environment by using an atomizer or replacing a standard high pressure gas cylinder.

The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims (8)

1. A TDLAS high temperature, high pressure calibration system, comprising: a high-pressure chamber, a high-pressure control module, a high-temperature tube furnace, a temperature control and display module and a measuring light path;

The high-pressure chamber comprises a left end cover flange and a right end cover flange which are respectively used for sealing two ends of the high-pressure chamber, the upper end of the high-pressure chamber is welded with a high-pressure air inlet port and is connected through a stainless steel clamping sleeve joint, and the high-pressure chamber is used for providing target gas with preset pressure and uniformly filling the target gas into a measuring area in the center of the furnace tube;

The high-temperature tube furnace is arranged in the high-pressure chamber and comprises a furnace tube, a heating wire, a temperature control thermocouple and a temperature thermocouple, wherein the heating wire is wound on the surface of the furnace tube, the temperature control thermocouple is used for PID temperature control feedback of the high-temperature tube furnace, and the temperature thermocouple is arranged in the center of the furnace tube and used for monitoring the temperature of the center of the furnace tube;

The upper end of the high-temperature chamber is welded with a power supply and thermocouple interface which is used for connecting a heating wire, a temperature control thermocouple, a temperature measurement thermocouple and a temperature control and display module, and the temperature control and display module is used for PID temperature control of the high-temperature tube furnace and displaying the temperature in the center of the furnace tube;

The measuring light path is located on the central axis of the furnace tube and comprises a first light guide column, a measuring area and a second light guide column, the measuring area is located between the first light guide column and the second light guide column, and the first light guide column and the second light guide column are respectively and fixedly installed on the left end cover flange and the right end cover flange.

2. The TDLAS high temperature and high pressure calibration system of claim 1, wherein the measurement light path further comprises a collimator lens, a left end cover quartz window and a right end cover quartz window, the collimator lens is fixedly mounted on the left side of the left end cover sealing flange, and the left end cover quartz window and the right end cover quartz window are respectively mounted at the centers of the left end cover flange and the right end cover flange.

3. The TDLAS high temperature and high pressure calibration system of claim 1 or 2, wherein the hyperbaric chamber further comprises three water jackets, a first water jacket, a second water jacket, and a third water jacket in sequence from left to right, the centers of the left and right end flanges being provided with annular water jackets for cooling the left and right end flanges, the left and right end cover quartz panes, the first and second light guide posts, respectively.

4. A TDLAS high temperature and high pressure calibration system according to claim 3, wherein the body of the hyperbaric chamber is cylindrical, stainless steel is used, and the three water jackets are stainless steel cylinders.

5. The TDLAS high temperature and high pressure calibration system according to claim 1 or 2, wherein the high pressure control module comprises a high pressure gas cylinder for filling high pressure gas, a pressure controller for controlling a pressure value of the gas to a predetermined value, an atomizer for atomizing distilled water into water vapor, and a heat tracing pipe for heating the gas.

6. The TDLAS high temperature and high pressure calibration system of claim 5, wherein the high pressure gas cylinder, the pressure controller, the atomizer, and the heat trace pipe are connected by metal tubes and sealed by stainless steel ferrule fittings.

7. The TDLAS high temperature and high pressure calibration system according to claim 1 or 2, wherein the high temperature tube furnace further comprises a heat insulation layer, the heat insulation layer is wrapped on the outer layer of the furnace tube, the high temperature tube furnace is a three-section tube furnace, the heating wire is a three-section temperature control, and three temperature control thermocouples are uniformly distributed between the heating wire and the heat insulation layer and are used for carrying out PID temperature feedback on the high temperature tube furnace.

8. The TDLAS high temperature and high pressure calibration system of claim 1 or 2, wherein the temperature control and display module comprises a support plate, a touch display screen, a control circuit board, the support plate for supporting a high pressure chamber and a built-in high temperature tube furnace; the heating wire, the temperature control thermocouple and the temperature thermocouple are connected with the control circuit board through a power supply and a thermocouple interface, and the touch display screen is used for displaying the temperature in real time and setting temperature control parameters.