CN104764609A - Comprehensive optical measurement platform of aero-engine main combustion chamber - Google Patents

Abstract

The invention discloses a comprehensive optical measurement platform for the main combustion chamber of an aero-engine. A variety of optical measurement methods are used to comprehensively measure the parameters inside the combustion chamber of the aero-engine. The incoming air enters the equal straight pressure stabilizing section from the intake circular section, and the combustion test section is fixedly installed between the diffuser and the outlet square section, and the air flows through the diffuser to decelerate and diffuse into the combustion test section. Glass observation windows are mounted on both sides of the combustion test section for optical measurement; in the cold test, the airflow flows out from the outlet of the single-head rectangular test piece and then enters the cold flow tee, the outlet of the main road is closed, and the airflow flows out from the bypass. For high-temperature pure air flow, based on the combustion experiment equipment, a single-head test piece can be used to measure kerosene atomization, velocity, temperature and composition in the combustion chamber, complete the test experiment of the flow field in the combustion chamber of the aero-engine, and realize the aero-engine Fine measurement of combustion flow field.

Description

A comprehensive optical measurement platform for the main combustion chamber of an aero-engine

technical field

The invention relates to the technical field of aero-engine optical measurement, in particular to a comprehensive optical measurement platform for the main combustion chamber of an aero-engine.

Background technique

For the measurement of temperature, pressure, velocity and composition, thermocouples, piezoelectric sensors, dynamic and static pressure tubes, hot wire anemometers and gas analyzers have long relied on various physical probes or measuring instruments. Its shortcomings are that the results need to be corrected carefully because the physical probe is easy to interfere with the flow field or be disturbed; because it is easy to be restricted by the environment, the scope of use is limited; because it generally feels the macroscopic average physical quantity, it lacks sufficient spatial and temporal resolution wait.

Different from the contact measurement method that would interfere with the measurement of the flow field in the past, many advanced non-contact measurement methods have appeared in recent decades with the rapid development of science and technology in the fields of computer and optics, such as PIV (Particle Image Velocimetry), CARS (Coherent anti-Stokes Raman Scattering) and TDLAS (Tunable Diode Laser Absorption Spectroscopy), etc.; among them, PIV is widely used in the measurement of cold flow field, and TDLAS and CARS are used as laser spectroscopic temperature measurement methods in the combustion chamber. It is less used in the measurement of combustion zone temperature.

Foreign optical measurement systems have a wide range of specialties and a complete range of categories. In China, before the mid-1990s, although there were very few theoretical researches, it was not until the mid-1990s that the experimental and theoretical researches on optical measurement could be carried out systematically. There are many domestic optical measurement platforms, but few comprehensive optical measurement platforms.

Contents of the invention

In order to avoid the deficiencies in the prior art, the invention proposes a comprehensive optical measurement platform for the main combustion chamber of an aero-engine.

The technical solution adopted by the present invention to solve the technical problems is: the comprehensive optical measurement platform of the main combustion chamber of the aero-engine, including the optical measurement system, which is characterized in that it also includes the air intake circle turning square section, the constant pressure stabilizing section, the diffuser The device, the combustion test section, the cold flow tee, the rear observation window, the water-cooled section of the hot flow outlet, the square-to-round section of the outlet, the orifice plate, and the round-to-square section of the intake are installed at the front end of the constant pressure section. It is fixedly connected with the diffuser, and the combustion test section is located between the diffuser and the outlet square-circle section. The side mounted glass observation window is used for optical measurement, the cold flow tee is fixedly connected with the outlet square and circular section, the orifice plate and the rear observation window are installed on the bypass road, and the pressure regulating valve is installed on the main road, and the orifice plate and the pressure regulating valve cooperate to adjust The pressure in the combustion chamber; in the cold state experiment, the air flow passes through the cold flow tee bypass and enters the water cooling section of the hot flow outlet to exhaust; in the hot state experiment, the air flow passes through the rectangular water cooling piece to spray water to cool down and then enters the exit square turning circle section;

The optical measurement system performs PIV optical measurement on the combustion test section, sprays particles into the circular section of the air intake, the tracer particles scattered in the flow field move with the air flow, and expands the laser beam through the combined lens into a sheet of light to illuminate the flow field , use a digital camera to shoot the flow field to get the particle image, carry out correlation calculation on the particle image to get the quantitative velocity distribution in a section of the flow field, and obtain the distribution of flow field characteristic parameters such as flow field vorticity, streamline and isovelocity line after processing.

The particle diameter is less than 10 microns.

Beneficial effect

The integrated optical measurement platform of the main combustion chamber of the aero-engine of the present invention uses optical measurement means to simultaneously measure the concentration and temperature of oxygen in the flame of the aero-engine combustion chamber, and simultaneously measures multiple points, laser phase matching technology, spectral simulation, and supersonic combustion Were studied. The present invention carries out the measurement and research of kerosene atomization, PIV velocity field, CARS temperature, SVRS composition and TDLAS temperature field on the combustion chamber. The measurement is not easily restricted by the external environment, and the time and space resolution is high. Comparing the calculation results with the test results, it can be clearly seen that the jet flow of the upper and lower main combustion holes of the test model is basically symmetrical, and the low-velocity area of the main combustion zone is evenly distributed, and the simulation test results of the convection field are consistent.

The integrated optical measurement platform of the main combustion chamber of the aero-engine of the present invention, for the experimental piece with a single head and a rectangular shape, the equipment adopts a round-to-square section at the outlet, and after the round-to-square section is connected to the diffuser through a straight section, the air flows After being decelerated and diffused by the diffuser, it enters the single-head test piece of the engine; due to the need for optical measurement, there are observation windows on both sides of the test section. Three-way, the outlet of the main road is closed, the optical measurement is carried out at the glass observation window, and the airflow flows out from the bypass. For high-temperature pure air flow, based on this combustion chamber experimental equipment, a single-head test piece can be used to measure kerosene atomization, velocity, temperature and composition in the combustion chamber, and complete the flow field test experiment in the combustion chamber of the aero-engine to realize Fine measurement of aero turbine engine combustion flow field.

Description of drawings

An integrated optical measurement platform for the main combustion chamber of an aero-engine according to the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Fig. 1 is a schematic diagram of the front and rear transition sections in the cold flow state of the present invention.

Fig. 2 is a cross-sectional view of the front and rear transition sections in the cold flow state of the present invention.

Fig. 3 is a schematic diagram of the front and rear transition sections in the combustion state of the present invention.

Fig. 4 is a cross-sectional view of the front and rear transition sections in the combustion state of the present invention.

Fig. 5 is a schematic diagram of the combustion test section of the present invention.

Fig. 6 is a streamline diagram obtained by CFD calculation of the present invention.

Fig. 7 is a streamline diagram obtained by PIV optical measurement of the present invention.

In the picture:

1. Intake circular turning section 2. Constant pressure stabilizing section 3. Diffuser 4. Combustion test section 5. Cold flow tee 6. Rear observation window 7. Hot flow outlet water cooling section 8. Outlet turning round section 9 .Orifice plate

Detailed ways

This embodiment is a comprehensive optical measurement platform for the main combustion chamber of an aero-engine.

Referring to Figures 1 to 7, the optical measurement platform for the main combustion chamber of an aero-engine consists of an intake circle section 1, a constant pressure stabilization section 2, a diffuser 3, a combustion test section 4, a cold flow tee 5, and a rear observation window 6. It is composed of water-cooling section 7 at the heat outlet, circular section 8 at the outlet, orifice plate 9 and an optical measurement system. For the test piece that is a single-head rectangular test piece, since the heater outlet of the original equipment is a circular outlet, it is first necessary to design the round and square section of the equipment intake, and after the circle is turned to the square, it will go through a section of equal straight voltage stabilizing section to connect the expansion of the test piece. Compressor, the air flows through the diffuser to decelerate and diffuse, and enters the single-head test piece of the engine; in the cold test, the airflow flows out from the outlet of the single-head rectangular test piece and then enters the cold flow tee, and the main road exit is closed. Air flows out through the bypass. For high-temperature pure air flow, based on this combustion chamber experimental equipment, a single-head test piece can be used to measure kerosene atomization, velocity, temperature and composition in the combustion chamber, and complete the test experiment and measurement of the flow field in the combustion chamber of the aero-engine .

The design of the cold flow tee section, due to the need for optical measurement, in the cold state experiment, the airflow flows out from the outlet of the single-head rectangular test piece and enters the cold flow tee 5, the main road exit is closed, and the glass observation window is used for optical measurement. Air flows out through the bypass. According to the CFD numerical simulation calculation, the influence range of the vortex return flow in the main channel of the cold flow tee is small, and the bypass airflow flows smoothly, which has little influence on the upstream flow, which meets the experimental requirements of the single-head combustor.

The design of the water-cooling section of the heat flow outlet, because the outlet temperature of the combustion chamber is as high as 1500K or more, the outlet section needs to be water-cooled when it is processed with stainless steel. According to the heat flow and strength check of the wall heat conduction, it meets the strength and heat transfer requirements.

For the design of the outlet pressure regulation, due to the adjustment of the combustion chamber under different working conditions, it is necessary to install a pressure regulating valve downstream of the combustion experiment section, which is divided into two paths downstream of the combustion experiment section. The pressure valve, according to the different working conditions of the combustion chamber, selects orifice plates with different apertures, and cooperates with the pressure regulating valve of the main circuit to realize large-scale and high-precision pressure adjustment in the combustion chamber.

The heater system of the experimental equipment can simulate the total temperature of the incoming flow of 300-1000K, the incoming airflow of 0.1-4.0MPa, the incoming flow rate of 0.0-1.0kg/s, and the experimental gas is pure high-enthalpy air.

work process:

The incoming air passes through the filter and directly enters the air distribution platform to obtain the required incoming flow conditions; the air flow passes through the mixer to distribute the air evenly; The air of the heater is mixed evenly again; the outlet of the mixer is connected with a tee, and the incoming air is divided into two paths, one path enters the experimental model through the equipment nozzle, and the other path is a bypass system, which is discharged outside after being cooled by the water tank; the bypass system A non-standard self-made water cooling radiator system is used to cool the high-temperature air, the cooling medium is water, the radiator is placed in the water tank, and tap water is used for water supply and circulation; the main road system is successively equipped with an air intake circular turn square section 1, and a straight and constant pressure section 2 and diffuser 3, the diffuser 3 makes the incoming flow pressurized and decelerated, and the air flow enters the combustion test section 4 of the aero turbine engine after passing through the diffuser 3; in the cold state test, the air flow passes through the cold flow tee 5 structural member bypass It enters the outlet circular section 8, and is divided into two outlets through the cold flow tee 5, and the outlet two outlets are respectively adjusted by the orifice plate 9 and the solenoid valve; in the hot state experiment, the air flows through the rectangular water-cooled piece to spray water to cool down. Enter the exit circle and turn to section 8.

PIV optical measurement system includes laser, synchronizer, high-speed camera and image calculation software. When performing PIV optical measurement on the experimental model, particles are first injected into the air inlet circular section 1, so that a large number of tracer particles are scattered in the flow field to follow the movement of the flow field; the double-pulse laser is mainly used as an illumination source, and two pulse lasers are used. The laser is superimposed on one surface in space through the beam combiner, irradiated through an optical path exit, and passes through the light guide arm and the sheet light source system to generate a pulsed sheet light source for illuminating the flow field. Since a large number of tracer particles with a particle size of less than 10 microns are distributed in the flow field to follow the movement of the flow field, the laser beam is expanded into a sheet of light through a combined lens. After the sheet of light passes through the observation window 6 to illuminate the flow field, a digital camera is used to burn The left observation window of test section 4 took pictures of the flow field, and the right observation window used a blackened blind plate as the background, and obtained two frames of particle images before and after, and carried out correlation calculation on the particle images in the images to obtain the flow field in a section plane. Quantitative velocity distribution. Further processing can obtain the distribution of flow field characteristic parameters such as flow field vorticity, streamline and constant velocity line. When performing TDLAS and CARS optical measurements on the experimental model, lasers are fired on the observation windows on both sides of the combustion test section 4, and the optical path is reasonably arranged to measure the temperature of a specific point of the test piece. TDLAS measures the temperature along the two paths around the main combustion hole. The integral temperature of ; CARS measures the temperature of each point in the main combustion zone.

The high-speed camera is mainly composed of a Charge Coupled Device, and the CCD is used as an image sensor. The CCD converts the image into a digital signal, triggers it once through an external trigger, and takes two frames of images in a very short time as a group. At the same time, multiple groups of images are captured The data is transferred to the computer memory and the captured image is displayed on the computer. The synchronizer generates a periodic pulse trigger signal when it passes through the interior, and generates a delay trigger signal through multiple delay channels to control the laser, high-speed camera and computer so that they work simultaneously and in coordination. The computer is used to store the image data provided by the image acquisition board, and the calculation, display and storage of the velocity field can be completed in real time through the PIV system software. The analysis software uses the image processing algorithm to restore the original image, and the measurement image of the test area can be obtained. The two-dimensional fast Fourier transform is used to calculate the correlation function. According to the definition of velocity, the displacement of the particle within a known time interval is measured to obtain its velocity. Simultaneous measurement of multiple particles can obtain the flow field distribution map.

Claims (2)

1. the integrated optical measuring table of an aeromotor main chamber, comprise optical measuring system, it is characterized in that: also comprise air inlet circle and turn square section, etc. straight pressure-stabilizing section, diffuser, burning test section, cold flow threeway, rear observation window, hot outlets water-cooled section, exporter turns round section, orifice plate, air inlet circle turns a square section and the straight pressure-stabilizing section leading section such as to be arranged on, be fixedly connected with diffuser etc. straight pressure-stabilizing section, combustion experiment section is positioned at diffuser and exporter turns between round section, combustion experiment section two ends by joint flange respectively with diffuser, exporter turns round section and is fixedly connected with, combustion experiment section both sides mosaic glass observation window is used for optical measurement, cold flow threeway and exporter turn round section and are connected, bypass is provided with orifice plate and rear observation window, main road is provided with pressure regulator valve, orifice plate coordinates with pressure regulator valve and regulates internal pressure of combustion chamber, in Cold simulating test, air-flow enters the exhaust of hot outlets water-cooled section through cold flow threeway bypass, in Thermal-state test, air-flow turns round section through the laggard inlet/outlet side of rectangle water-cooled part spray cooling,

Optical measuring system carries out PIV optical measurement to burning test section, turn square section at air inlet circle and spray into particle, the trace particle dispensed in flow field is with air motion, laser beam is expanded optical illumination flow field in blocks through compound lens, digital camera shooting flow field is used to obtain particle picture, the velocity distribution that correlation computations obtains the tangent plane quantification in flow field is carried out to particle picture, and obtains the characteristic parameter of the flow field distributions such as flow field vorticity, streamline and line of equal velocity after process.

2. the integrated optical measuring table of aeromotor main chamber according to claim 1, is characterized in that: particle diameter is less than 10 microns.