CN108008062A - Laser ignition combustion chamber is used in a kind of titanium fire experiment - Google Patents

Abstract

The invention belongs to the technical field of titanium alloy application and relates to a laser ignition combustion chamber for a titanium fire test. The combustion chamber is mainly composed of shell, front cover, rear cover, intake pipe, exhaust pipe, sample holder, pressure plate, cooling water pipe, observation window, laser incident window, gas temperature sensor and gas pressure sensor. The ignition method can ignite the test sample in a very short time; the sealed combustion chamber and the intake pipe close to the test sample are used to realize the simultaneous adjustment and maintenance of the pressure, temperature and airflow velocity in the chamber; the observation window is located directly above the sample, which is convenient for observing the combustion situation ; There is a cooling structure in the wall of the shell, which can realize the titanium fire test above 600 ℃; the sample fixture is fixed by pressing plate, which is convenient for installation. The combustion chamber provided by the invention is compact in structure, low in use cost, capable of carrying high temperature, high pressure and high speed airflow conditions, meets the requirements of a titanium fire test under the interaction of simulated aeroengine service environment, and has broad application prospects.

Description

Laser ignition combustion chamber for titanium fire test

technical field

The invention belongs to the technical field of titanium alloy application and relates to a laser ignition combustion chamber for a titanium fire test.

Background technique

Titanium alloys have a safety hazard of burning in the high-temperature, high-pressure and high-speed airflow environment of aero-engines, resulting in titanium fire failures. In addition to more than 100 titanium fires in the United States and Russia, several titanium fires have also occurred during the development of advanced engines in my country in recent years. The problem of titanium alloy combustion has attracted great attention.

The titanium fire test is the core and key to scientifically evaluate the combustion characteristics of titanium alloys in the engine service environment. External energy such as high-energy friction, laser and liquid droplets can be used as ignition sources. Among them, laser is a safe, reliable and clean new ignition technology, which has the characteristics of high energy density and fast ignition speed. It is applied to the titanium fire test, which can realize the controllable ignition position and quantitatively characterize the combustion process. basic features.

The United States took the lead in using laser ignition technology to evaluate the safety of engine titanium fire, and established a special combustion device for titanium fire test at Wright-Patterson Air Force Base and Pratt & Whitney Engine Factory, which realized high temperature, high pressure and high speed airflow conditions. The combustion test of titanium alloy provides technical support for F119 and other advanced engines to effectively prevent titanium fire. However, due to technical blockade and other reasons, my country's titanium fire test technology research is still in its infancy, and existing combustion chambers or devices cannot meet the needs of advanced engine development.

Contents of the invention

The purpose of the present invention is to provide a laser ignition combustion chamber capable of adjusting and maintaining the temperature, pressure and velocity of the gas flow in view of the deficiencies of the prior art.

The technical solution of the present invention is to provide a laser ignition combustion chamber for titanium fire test, using laser as the ignition source, the combustion chamber includes a shell (1), a front cover (2), a rear cover (3), an intake pipe (4), exhaust pipe (5), sample holder (6), cooling water pipe (8), observation window (9), laser incident window (10), gas temperature sensor (11) and gas pressure sensor (12); The wall of the housing (1) is embedded with a cooling water channel (104), the cooling water channel is connected to the external cooling water pipe (8) (through welding or threaded connection), and the cooling water pipe and the cooling water channel pass into the cooling water to the housing cooling to prevent the housing temperature from being too high caused by hot air; there are three openings on the housing wall, which are respectively sealed and fixed to install the sample holder (6), the observation window (9) and the laser incident window (10);

The external laser is incident into the housing through the laser incident window (10);

The sample holder (6) is used to install and fix the sample in the housing;

The observation window is used to observe the sample from the outside of the shell;

The front cover (2) and the rear cover (3) are respectively sealed and connected to both ends of the housing (1) to form a closed cavity;

The air intake pipe (4) is connected to the front cover (2), and the air intake pipe (4) passes through the front cover (2) and extends into the cavity;

The exhaust pipe (5) is connected to the front cover (2), and the exhaust pipe (5) passes through the rear cover (3) and extends into the cavity;

A gas temperature sensor (11) and a pressure sensor (12) respectively protrude into the cavity of the housing (1) through the front cover (2), and are used to measure the gas temperature and gas pressure near the sample.

Further, a pressing plate (7) is also included. The pressing plate (7) is used to press the sample holder onto the housing, and the pressing plate is screwed to the housing through two bolts.

Further, the distance between the end of the intake pipe and the test sample is 20-50 mm. In order to allow the incident gas to be sprayed directly onto the surface of the test sample.

Further, both the gas temperature sensor (11) and the pressure sensor (12) are 10-30mm away from the test sample. Measure the gas temperature and gas pressure near the sample.

Further, the observation window (9) is located directly above the test sample, the observation window (9) is a cover plate with a window, and a quartz glass sheet is used as the window, and the cover plate is fixed to the housing opening (102) by bolts, and the quartz glass sheet and the The sealing connection between the cover plates. When the equipment is running, a high-speed camera can be installed directly above the observation window to observe the sample in the chamber, or an infrared temperature sensor can be installed to measure the temperature of the sample.

Further, the angle between the laser incident window (10) and the housing centerline is less than 90°, and the laser incident window is made of a material with a transmittance higher than 80%. The laser can be accurately irradiated on the sample after it enters the chamber of the combustion chamber perpendicular to the laser incident window.

Further, the sample holder (6) includes a first clamping plate (601), a second clamping plate (602), a support rod (603), an end cover (604) and a handle (605); the first clamping plate (601) and the second clamping plate (602) is used to clamp the sample; the first clamping plate (601) and the second clamping plate (602) are both sleeved on the front end of the support rod (603), and can rotate around the support rod (603) to adjust the sample and the incident air flow or the sample and Angle between the incident lasers; the rear end of the support rod (603) is fixedly connected or integrally formed with the end cover (604), the end cover (604) is used to seal and fix the opening of the housing, and the end cover (604) has a handle .

Further, the front cover (2) has a central hole for welding the air intake pipe (4), on both sides of the central hole there are mounting holes for the gas temperature sensor (11) and for the gas pressure sensor (12), and the secondary outer ring has cooling The water pipe hole is used to pass the cooling water pipe (8). The diameter of the cooling water pipe hole is slightly larger than the outer diameter of the cooling water pipe (8). Cover (3) structure is basically the same as front cover (2), but there are no gas temperature sensor (11) mounting holes and gas pressure sensor (12) mounting holes.

Further, the first splint and the second splint of the sample fixture have the same structure, and the heads are all circular arc structures, with holes for fitting on the support rods. Two clips are extended from the arc, and the middle of the clips is used for The sample is placed, and there are holes on both sides of the clip, which are used to pass through the bolts to clamp the sample.

The intake pipe and the exhaust pipe are respectively connected with the front cover and the rear cover by welding.

The present invention has the following advantages and outstanding effects:

1) The combustion chamber provided by the present invention can carry high temperature, high pressure and high speed airflow conditions, and meet the needs of the titanium fire test under the simulated engine service environment. At the same time, the laser ignition method can be used to ignite the test sample in a very short time; 2) The wall of the shell of the combustion chamber is equipped with a cooling structure, which greatly improves the temperature resistance of the equipment, and can realize the titanium fire test above 600 °C; 3) The gas outlet end of the intake pipe of the combustion chamber is relatively close to the test sample, so that the surface The airflow velocity is close to or equal to the airflow velocity of the intake pipe. This design avoids increasing the airflow velocity in the entire cavity in order to achieve the airflow velocity on the sample surface. It only needs to increase the airflow velocity of the intake pipe, and the gas flow rate is reduced under the same airflow velocity. Furthermore, the power of the gas heater is reduced; 4) An observation window is set directly above the sample to observe and record the burning process of the sample in real time, and the ignition temperature of the sample can also be measured by an infrared temperature sensor; 5) The test sample can be rotated around the support rod of the sample fixture , can adjust the angle between the sample and the incident airflow and incident laser; 6) The sample holder can hold two or more samples, which can realize the combustion of multiple groups of samples; 7) The combustion chamber is compact in structure, easy to operate and low in cost low and has broad application prospects.

Description of drawings

Fig. 1 is the structural assembly diagram of the laser ignition combustion chamber for titanium fire test provided by the present invention.

FIG. 2 is an internal structure diagram of FIG. 1 .

Fig. 3 is a housing diagram shown in Fig. 1 . Fig. 4 is a front cover diagram shown in Fig. 1 .

Fig. 5 is a diagram of the sample fixture shown in Fig. 1 .

Fig. 6 is a front view of the first or second splint shown in Fig. 5 .

Fig. 7 is a top view of the first or second splint shown in Fig. 5 .

Among them: 1-shell, 2-front cover, 3-rear cover, 4-intake pipe, 5-exhaust pipe, 6-sample fixture, 7-press plate, 8-cooling water pipe, 9-observation window, 10-laser Incident window, 11-gas temperature sensor, 12-gas pressure sensor, 101-opening for installing sample holder, 102-opening for observation window, 103-opening for laser incident window, 104-inside of housing wall 601-first splint, 602-second splint, 603-support rod, 604-end cover, 605-handle.

Detailed ways

The present invention is a kind of laser ignition combustion chamber for titanium fire test, as shown in Figure 1, 2, 3, provides a kind of laser ignition combustion chamber for titanium fire test, adopts laser as ignition source, and described combustion chamber comprises shell ( 1), front cover (2), rear cover (3), intake pipe (4), exhaust pipe (5), sample holder (6), cooling water pipe (8), observation window (9), laser incident window ( 10), a gas temperature sensor (11) and a gas pressure sensor (12); the wall of the housing (1) is embedded with a cooling water channel (104), and the cooling water channel is connected with the external cooling water pipe (8) (by welding or screw thread connected with each other), the cooling water pipe and the cooling water channel are passed into the cooling water to cool the shell to prevent the shell temperature from being too high caused by hot air; there are three openings on the shell wall, which are respectively sealed and fixed to install the sample fixture (6), observation window (9) and laser incident window (10);

The external laser is incident into the housing through the laser incident window (10);

The sample holder (6) is used to install and fix the sample in the casing;

The observation window is used to observe the sample from the outside of the shell;

The front cover (2) and the rear cover (3) are respectively sealed and connected to both ends of the housing (1) to form a closed cavity;

The air intake pipe (4) is connected to the front cover (2), and the air intake pipe (4) passes through the front cover (2) and extends into the cavity;

The exhaust pipe (5) is connected to the front cover (2), and the exhaust pipe (5) passes through the rear cover (3) and extends into the cavity;

A gas temperature sensor (11) and a pressure sensor (12) respectively protrude into the cavity of the housing (1) through the front cover (2), and are used to measure the gas temperature and gas pressure near the sample.

Further, a pressing plate (7) is also included. The pressing plate (7) is used to press the sample holder onto the housing, and the pressing plate is screwed to the housing through two bolts.

Further, the distance between the end of the intake pipe and the test sample is 20-50 mm. In order to allow the incident gas to be sprayed directly onto the surface of the test sample.

Further, both the gas temperature sensor (11) and the pressure sensor (12) are 10-30mm away from the test sample. Measure the gas temperature and gas pressure near the sample.

Further, the observation window (9) is located directly above the test sample, the observation window (9) is a cover plate with a window, and a quartz glass sheet is used as the window, and the cover plate is fixed to the housing opening (102) by bolts, and the quartz glass sheet and the The sealing connection between the cover plates. When the equipment is running, a high-speed camera can be installed directly above the observation window to observe the sample in the chamber, or an infrared temperature sensor can be installed to measure the temperature of the sample.

Further, the angle between the laser incident window (10) and the housing centerline is less than 90°, and the laser incident window is made of a material with a transmittance higher than 80%. The laser can be accurately irradiated on the sample after it enters the chamber of the combustion chamber perpendicular to the laser incident window.

As shown in Figure 5, sample holder (6) comprises first clamping plate (601), second clamping plate (602), support bar (603), end cap (604) and handle (605); First clamping plate (601) and The second clamping plate (602) is used to clamp the sample; the first clamping plate (601) and the second clamping plate (602) are set on the front end of the support rod (603), and can rotate around the support rod (603) to adjust the sample and the incident airflow Or the angle between the sample and the incident laser; the rear end of the support rod (603) is fixedly connected or integrally formed with the end cover (604), the end cover (604) is used to seal and fix the opening of the shell, and the end cover (604) With handle.

As shown in Figure 4, the front cover (2) has a central hole for welding the intake pipe (4), and there are mounting holes for the gas temperature sensor (11) and the gas pressure sensor (12) on both sides of the central hole. The ring has cooling water pipe holes for passing the cooling water pipe (8), the diameter of the cooling water pipe hole is slightly larger than the outer diameter of the cooling water pipe (8), and the outer ring has bolt holes for fixing it to the shell (1) by bolts On, the rear cover (3) structure is basically the same as the front cover (2), except that there are no gas temperature sensor (11) mounting holes and gas pressure sensor (12) mounting holes.

As shown in Figures 6 and 7, the inner splint (601) and the outer splint (602) of the sample fixture have the same structure, and the heads are all circular arc structures, and there are holes for it to be sleeved on the support rod (603). Two clips are extended, the middle of the clip is used to place the sample, and there are holes on both sides of the clip, which are used to pass through the bolts to clamp the sample.

The present invention will be further described below in conjunction with specific examples, but the present invention is not limited to the following examples.

Example 1

As shown in Figures 1, 2, and 3, the shell (1) has a circular cross-section and is made of integral casting. Its outer diameter is 290mm, inner cavity diameter is 220mm, and there are connecting flanges at both ends. The diameter of the flange is 360mm, three bosses (101), (102), (103) diameters are respectively 200mm, 120mm and 80mm. The boss (101) installs the sample holder (6), which is pressed onto the boss (101) by two pressure plates, and the test sample is clamped to the sample holder (6) by the inner and outer splints (601) (602). The observation window (9) is made of quartz glass with a diameter of 88mm. It is fixed to the boss (102) of the observation window by a cover plate with holes through bolts. When the equipment is running, a high-speed camera can be installed directly above the observation window to observe the samples in the cavity. situation, or install an infrared temperature sensor to measure the sample temperature. The laser incident window (10) is located in front of the observation window (9), is made of zinc selenide, and has a diameter of 32mm. The body axis is at an angle of 45°, and the laser light enters the test cavity through the laser incident window perpendicular to it, and irradiates the surface of the test sample. The front cover (2) and the rear cover (3) are basically the same in structure, and both have a diameter of 360mm, and are connected to the flange of the housing (1) by bolts, and are sealed with a sealing ring between the housing (1). The intake pipe (4) and the exhaust pipe (5) have diameters of 40mm and 100mm respectively, and are respectively fixed to the front cover (2) and the rear cover (3) by welding. The end of the inlet pipe (4) is 20mm away from the sample, so that the incident gas can be directly sprayed onto the surface of the test sample. A gas temperature sensor (11) and a gas pressure sensor (12) are installed on the front cover (2) through sealing threads, and measure the gas temperature and pressure near the sample respectively. There are 10 cooling water channels (104) with a diameter of 10 mm in the wall of the housing (1), the cooling water pipes (8) are welded to the cooling water channels (104), and pass through the cooling water pipes of the front cover (2) and the rear cover (3) hole. During the test, firstly, the cooling water pipe (8) is passed into the cooling water to ensure cooling of the device, and the air inlet pipe (4) is passed into the high-temperature and high-pressure gas to enter the chamber, sprayed onto the surface of the sample, adjust the valve of the exhaust pipe, and wait until the temperature and pressure in the chamber . After the airflow speed is stable, the laser enters from the laser incident window (10) and irradiates the front of the sample, so that the sample can be heated up rapidly to ignite. A high-speed camera is installed above the observation window (9) to observe the sample in the chamber. The gas temperature sensor (11) and the gas pressure sensor (12) respectively measure the gas temperature and pressure near the sample.

Example 2

The shell (1) has a rectangular cross-sectional shape and is welded by four plates with cooling channels (104), and the three bosses (101), (102), and (103) are connected to the shell (1) by welding On the upper side, the boss (102) and the boss (103) are arranged on the upward side, the opening (101) is arranged on the side, so that the observation window (9) on the opening (102) is located directly above the test sample, and the opening (103 The laser incident window (10) on the ) is located at the oblique top of the test sample, the material of the observation window (9) is quartz glass, the material of the laser incident window (10) is zinc selenide, the observation window (9) and the laser incident window (10) There is a sealing ring between the opening of the casing and the casing to prevent the leakage of high temperature and high pressure gas. The opening (103) is arranged obliquely so that the laser beam incident perpendicular to the laser incident window (10) can just irradiate the surface of the test sample. The sample holder (6) is installed on the opening (101), and is pressed onto the opening of the casing by a pressure plate, and a sealing ring is provided between the end cover (604) of the sample holder (6) and the opening (101). Air intake pipe (4) and front cover (2), exhaust pipe (5) and rear cover (3) all adopt lathe processing method to manufacture as a whole, and front cover (2) and rear cover (3) all adopt welding method and The shells (1) are connected. The air inlet pipe (4) protrudes into the housing cavity and is close to the test sample, so that the incident gas can be directly sprayed onto the surface of the test sample, so that the air velocity on the surface of the sample is close to or equal to the incident air velocity. The gas temperature sensor (11) and the gas pressure sensor (12) are arranged on the side of the casing (1) opposite to the opening (101), and are connected with the casing (1) through sealing threads. The cooling water pipe (8) is welded on the cooling water channel (104). During the test, firstly, the cooling water pipe (8) is passed into the cooling water to ensure cooling of the device, and the air inlet pipe (4) is passed into the high-temperature and high-pressure gas to enter the chamber, sprayed onto the surface of the sample, adjust the valve of the exhaust pipe, and wait until the temperature and pressure in the chamber . After the airflow speed is stable, the laser enters from the laser incident window (10) and irradiates the front of the sample, so that the sample can be heated up rapidly to ignite. A high-speed camera is installed above the observation window (9) to observe the sample in the chamber. The gas temperature sensor (11) and the gas pressure sensor (12) respectively measure the gas temperature and pressure near the sample.

Claims (8)

1. A kind of laser ignition combustion chamber for titanium fire test, adopt laser as ignition source, described combustion chamber comprises shell (1), front cover (2), back cover (3), air inlet pipe (4), exhaust Tube (5), sample holder (6), cooling water pipe (8), observation window (9), laser incident window (10), gas temperature sensor (11) and gas pressure sensor (12); the casing (1) A cooling water channel (104) is embedded in the wall, and the cooling water channel is connected to the external cooling water pipe (8) (connected by welding or threading), and the cooling water pipe and the cooling water channel are fed with cooling water to cool the shell to prevent hot air The temperature of the casing is too high; there are three openings on the wall of the casing, which are respectively sealed and fixed to install the sample holder (6), the observation window (9) and the laser incident window (10); The external laser is incident into the housing through the laser incident window (10); The sample holder (6) is used to install and fix the sample in the housing; The observation window is used to observe the sample from the outside of the shell; The front cover (2) and the rear cover (3) are respectively sealed and connected to both ends of the housing (1) to form a closed cavity; The air intake pipe (4) is connected to the front cover (2), and the air intake pipe (4) passes through the front cover (2) and extends into the cavity; The exhaust pipe (5) is connected to the front cover (2), and the exhaust pipe (5) passes through the rear cover (3) and extends into the cavity; A gas temperature sensor (11) and a pressure sensor (12) respectively protrude into the cavity of the housing (1) through the front cover (2), and are used to measure the gas temperature and gas pressure near the sample. 2. a kind of laser ignition combustion chamber for titanium fire test as claimed in claim 1, is characterized in that: also comprise pressing plate (7), pressing plate (7) is used for sample holder is compressed on the shell, and pressing plate passes two A bolt is threadedly connected to the housing. 3. A laser ignition combustion chamber for a titanium fire test as claimed in claim 1 or 2, wherein the distance between the end of the intake pipe and the test sample is 20-50 mm. 4. a kind of laser ignition combustion chamber for titanium fire test as claimed in claim 1 or 2 is characterized in that: gas temperature sensor (11) and pressure sensor (12) are all apart from test sample 10～30mm. 5. a kind of laser ignition combustion chamber for titanium fire test as claimed in claim 1 or 2, is characterized in that: observation window (9) is positioned at test sample directly above, and observation window (9) is the cover plate with window, adopts quartz The glass sheet is a window, and the cover plate is fixed to the casing opening (102) by bolts, and the quartz glass sheet and the cover plate are sealed and connected. 6. A kind of laser ignition combustion chamber for titanium fire test as claimed in claim 1 or 2, is characterized in that: the angle that laser incident window (10) and housing center line is less than 90 °, laser incident window adopts transmittance Material above 80%. 7. A kind of laser ignition combustion chamber for titanium fire test as claimed in claim 1 or 2, is characterized in that: sample holder (6) comprises first splint (601), second splint (602), support rod (603 ), end cap (604) and handle (605); the first clamping plate (601) and the second clamping plate (602) are used to clamp the sample; the first clamping plate (601) and the second clamping plate (602) are set on the support rod (603) front end, and can rotate around the support rod (603) to adjust the angle between the sample and the incident airflow or the sample and the incident laser; the rear end of the support rod (603) is fixedly connected or integrally formed with the end cover (604), The end cover (604) is used for sealing and fixing with the casing opening, and the end cover (604) has a handle. 8. A kind of laser ignition combustion chamber for titanium fire test as claimed in claim 1 or 2, is characterized in that: front cover (2) has a center hole, is used for welding intake pipe (4), and center hole both sides have The gas temperature sensor (11) mounting hole and the gas pressure sensor (12) mounting hole, the secondary outer ring has a cooling water pipe hole for passing the cooling water pipe (8), the diameter of the cooling water pipe hole is slightly larger than the outer diameter of the cooling water pipe (8) , the outer ring has bolt holes for fixing it to the casing (1) by bolts, the structure of the rear cover (3) is basically the same as that of the front cover (2), except that there are no mounting holes for the gas temperature sensor (11) and gas pressure Sensor (12) mounting hole.