CN106872637A - The dynamic oxidation ablation test device and method of simulated engine blade Service Environment - Google Patents

Abstract

The invention discloses the dynamic oxidation ablation test device and method of a kind of simulated engine blade Service Environment.Described device includes the heater box of simulated engine blade working environment, the image capturing system outside window of high speed rotating unit and the opposing sidewalls observation on its side wall, and temperature feedback system；High speed rotating unit is connected with engine blade to be measured；Engine blade image before two high-speed camera sync pulse jammings test of image capturing system and in test process.It is analyzed by shooting image, realizes stress, the strain field quantitative measurment to engine blade under high temperature, flow at high speed service condition, obtains the engine blade dynamic process that the ablation of environment lower surface is developed under arms.

Description

The dynamic oxidation ablation test device and method of simulated engine blade Service Environment

Technical field

The present invention relates to the dynamic oxidation ablation test device and method of a kind of simulated engine blade Service Environment, belong to Engineering material, structural deformation and Experiments of Machanics technical field.

Background technology

Aero-engine plays key effect to the performance of aircraft and Flight Vehicle Design with manufacture.Although aeroplane engine The investigative technique difficulty of machine is big, high cost, but various countries will the research and development of aero-engine be placed in critical role.Because hair Motivation blade is thin, rotating speed big, so be easy to deform in high temperature, the engine operating environments of high pressure even damage, shadow Ring the work safety of engine.Therefore, it is necessary to carry out examination to the working condition under engine blade under arms intensity 's.

The method of existing research aero-engine is simulated including numerical simulation and experiment.Because engine Service Environment is answered Miscellaneous, so the method for numerical simulation still has significant limitation, experimental simulation is still to carry out most having for engine research, development Effect means.Experimental simulation is divided into two kinds, and the first is full ambient engine analogy method, and second is that full ambient engine factor is reduced into control The method of factor.Full ambient engine analogy method can directly obtain the experimental result of blade, and closer to real Service Environment, But full ambient engine analogy method is in the with high costs of equipment aspect.Full ambient engine factor is reduced to the method for governing factor from starting Machine blade Service Environment is set out with the essential reason that engine blade is destroyed, the working environment of simulated engine blade, The examination to engine blade working condition is completed in the case of low cost.

The content of the invention

It is an object of the invention to provide a kind of simulated engine blade Service Environment dynamic oxidation ablation test device and Method, the device can realize ablation experiments of the engine blade under real operating environments, realize to engine blade deformation Measurement；The dynamic oxidation ablation method of testing of simulated engine blade Service Environment is proposed on this device basic simultaneously.

Technical scheme is as follows：

A kind of dynamic oxidation ablation test device of simulated engine blade Service Environment, including heater box, rotation at a high speed Device, temperature feedback system and image capturing system, wherein：The high speed rotating unit is arranged on a side wall of heater box On, it includes part and the part being embedded into heater box outside heater box, and the part being embedded into heater box is high temperature resistant Material is made, with the part being connected with engine blade；Sight is provided with the heater box side wall relative with high speed rotating unit Window is examined, described image acquisition system is located at observation outside window, including two high-speed camera, two blue-light sources with filter plate And computer, two high-speed cameras realize Synchronization Control by a trigger by computer；The temperature feedback system is used In regulation and control heater box temperature, its temperature-measuring part is located in heater box.

In above-mentioned test device, the exotic material is preferably high temperature ceramic material.The high speed rotating unit can To be an engine, the casing that engine is embedded into part in heater box is high temperature ceramic material；It is connected with engine blade Part be usually the external gear that exotic material is made, the external gear is engaged with the internal gear at engine blade center.

The observation window is preferably high quartz glass window, can set two observation windows, two high-speed cameras point The ablation process on engine blade surface is not recorded through two observation windows；Two blue-light sources are used under hot conditions Light filling.

The temperature feedback system is the temperature feedback system of closed-loop control, and its temperature-measuring part is preferably Thermistor Temperature Measurement dress Put.

Further, to prevent the engine blade for rotating at a high speed from brittle failure occurring in test process, fragment clashes into heating Case then causes heater box to be damaged, and protection device, such as asbestos gauge, wire netting etc. are set in the periphery of inner wall of heater box.

Dynamic oxidation ablation test device based on above-mentioned simulated engine blade Service Environment, the invention provides one kind The dynamic oxidation ablation method of testing of simulated engine blade Service Environment, comprises the following steps：

1) engine blade to be measured is installed in high speed rotating unit, before ablation test, is taken the photograph by two high speeds Camera shoots two images of engine blade under normal temperature through observation window, used as not deformed initial pictures；

2) start test, the service temperature (usually 1500 DEG C) of engine blade will be heated to inside heater box, and open High speed rotating unit is opened, the rotating speed (such as 150r/s) when making engine blade rotating speed reach military service, while two high-speed cameras Captured in real-time is proceeded by, stops shooting after a period of time；

3) the engine blade image for shooting the diverse location for obtaining is moved to by phase by the operation matrix of rigid body displacement Same position, eliminates rigid body displacement；

4) the engine blade image photographed to test process using Digital Image Correlation Method is carried out with initial pictures Comparative analysis is processed, and is calculated the ess-strain after engine blade ablation, and engine blade environment following table under arms The dynamic process that face ablation is developed.

Above-mentioned steps 3) engine blade can be selected by feature identification technique, and matrix operation is utilized by high-speed camera Machine shoots the engine blade image rotation that obtains to same position.

Above-mentioned steps 4) first for every one group of image of high-speed camera shooting, by Digital Image Correlation Method to surveying The ablation pattern of examination process is analyzed with initial pictures：Every image is accordingly divided into some sub-districts first, for becoming Every bit (x, y) in initial pictures before shape has gray value f (x, y), the every bit in ablation pattern after deformation (x ', y ') has a new gray value g (x ', y '), and following correlation function is calculated for each sub-district：

Wherein (x, y) represents the coordinate before deformation, and (x ', y ') represents the coordinate after deformation, and M represents selected image subsection The half of width, f (x, y) represents the gray value function before deformation, and g (x ', y ') represents the gray value function after deformation, f_mRepresent Average gray value before deformation, g_mThe average gray value after deformation is represented,Wherein u, v distinguish Horizontally and vertically direction displacement is represented,Correlation function is represented, by pair correlation functionExtreme value is sought, can be asked Obtain the displacement (u, v) of every bit.Three-dimensional measurement is realized by two video cameras.

Then strain field (ε is calculated by displacement field_x,ε_y,γ_xy)；Stress field can be calculated further according to below equation：

Wherein E is the elastic modelling quantity of test material, and μ is material Poisson's ratio.

Obtain being started so as to obtain the ess-strain situation after engine blade ablation, and be shot by camera The machine blade dynamic process that ablated surface develops in environment under arms.

The present invention compared with prior art, with advantages below and high-lighting effect：Devise simulated engine blade work Make the closing space of environment, the control to temperature can be realized, while recording specified temp come real-time monitored by high-speed camera The oxidation ablation mechanism of lower blade of aviation engine；It is again that image-recognizing method is skilful with high-speed photography in terms of interpretation of result Combine wonderfully, the engine blade of the diverse location that will be photographed by matrix operation moves to same position, be allowed to suitable For Digital Image Correlation Method.Can to stress of the engine blade material under the service conditions such as high temperature, flow at high speed, should Variable field carries out quantitative measurment.The present invention realizes the simulation to engine blade working environment under laboratory condition, is research material The oxidation ablation behavior of material provides new an experimental provision and experimental technique.

Brief description of the drawings

Engine blade and engine connection signal in the dynamic oxidation ablation test process that Fig. 1 is provided for the present invention Figure.

A kind of knot of the dynamic oxidation ablation test device of simulated engine blade Service Environment that Fig. 2 is provided for the present invention Structure principle schematic.

In figure：External gear, 4- engine high-temperatures on 1- engine blades, the internal gear of 2- blade centers, 3- engines Part outside heater box of ceramic segment, 5- engines, 6- Thermistor Temperature Measurements device, wire netting under wire netting, 7b- on 7a-, First observation window of 8a-, second observation window of 8b-, first high-speed camera of 9a-, 9b- second high-speed camera, 10- add Hot tank, first blue-light source of 11a-, second blue-light source of 11b-.

Specific embodiment

Concrete structure of the invention, the course of work and implementation method are further illustrated below in conjunction with the accompanying drawings.

A kind of dynamic oxidation ablation test device structure such as Fig. 2 for simulated engine blade Service Environment that the present invention is provided It is shown.The test device includes heater box 10, and engine is provided with the side wall of heater box 10, and the engine includes being located at Refractory ceramics part 4 in heater box 10 and the part outside case 5, refractory ceramics part 4 are provided with external gear 3, the external tooth Wheel is engaged with the internal gear 2 at the center of engine blade 1, is rotated (referring to Fig. 1) by driven by engine blade 1；In relative heating Two observation windows 8a and 8b are provided with the wall of case side, image collecting device is set outside observation window.

Described image harvester includes two high-speed cameras 9a, 9b and two light sources 11a, 11b, and first high speed is taken the photograph Camera 9a and second high-speed camera 9b are respectively through first observation window 8a and second observation window 8b record engine leaf The ablation process of piece 1；First light source 11a and second light source 11b are respectively through first observation window 8a and second observation Window 8b in heater box 10 to irradiating blue light.

Thermistor Temperature Measurement device 6 is provided with heater box 10, the temperature feedback system of closed-loop control is formed, by feeding back to Temperature in road regulation heater box 10.

To prevent the engine blade for rotating at a high speed from occurring to clash into heater box after brittle failure, heater box is then caused to be damaged, In the inside upper and lower side of heater box 10, wire netting 7a and lower wire netting 7b is set.

Dynamic oxidation ablation device based on above-mentioned simulated engine blade Service Environment, there is provided dynamic oxidation ablation survey Method for testing comprises the following steps：

1) speckle is coated on engine blade to be measured.Before the rotation of engine blade 1, taken the photograph using two high speeds Camera 9a and 9b, shooting obtain the surface image at normal temperatures of engine blade 1, used as initial analysis image；

2) heater box 10 is opened, while being powered to engine, driven by engine blade 1 starts rotation, high-speed camera 9a Start to shoot with 9b, Thermistor Temperature Measurement device 6 starts thermometric.Heater box starts to protect when the temperature of heater box 10 reaches 1500 degrees Celsius Temperature.

3) after two high-speed cameras shoot within 10 minutes, stop shooting record.

4) heater box 10 is closed, makes temperature natural cooling in heater box 10.Continue to measure by Thermistor Temperature Measurement device 6 and add Temperature in hot tank 10.

5) blade of coating speckle is selected by feature identification technique, and is shot high-speed camera using matrix operation To blade to be measured rotate to same position.

6) ablation pattern on the engine blade surface collected to high-speed camera by Digital Image Correlation Method It is analyzed with the image being initially obtained, every image is accordingly divided into some sub-districts first, for not deformed preceding mesh Logo image (i.e. step 1) shoot initial pictures) every bit (x, y) have gray value f (x, y), target image after deformation (i.e. step 3) shoot ablation pattern) in every bit (x ', y ') have a new gray value g (x ', y '), for every height Area calculates following correlation function：

Wherein (x, y) represents the coordinate before deformation, and (x ', y ') represents the coordinate after deformation, and M represents selected image subsection The half of width, f (x, y) represents the gray value function before deformation, and g (x ', y ') represents the gray value function after deformation, f_mRepresent Average gray value before deformation, g_mThe average gray value after deformation is represented,Wherein u, v distinguish Horizontally and vertically direction displacement is represented,Correlation function is represented, by pair correlation functionExtreme value is sought, can be asked The displacement (u, v) of every bit is obtained, strain field can further be calculated by displacement field by local least square method fitting theory (ε_x,ε_y,γ_xy)；

7) stress field can be calculated according to below equation：

Wherein E is the elastic modelling quantity of test material, and μ is material Poisson's ratio.

Claims (10)

1. the dynamic oxidation ablation test device of a kind of simulated engine blade Service Environment, including heater box, high speed rotating dress Put, temperature feedback system and image capturing system, wherein：The high speed rotating unit is arranged on a side wall of heater box, It includes part and the part being embedded into heater box outside heater box, and the part being embedded into heater box is exotic material It is made, with the part being connected with engine blade；Observation window is provided with the heater box side wall relative with high speed rotating unit, Described image acquisition system is located at observation outside window, including two high-speed cameras with filter plate, two blue-light sources and meters Calculation machine, two high-speed cameras realize Synchronization Control by a trigger by computer；The temperature feedback system is used to adjust Control heater box temperature, its temperature-measuring part is located in heater box.

2. test device as claimed in claim 1, it is characterised in that the exotic material is high temperature ceramic material.

3. test device as claimed in claim 1, it is characterised in that the high speed rotating unit is an engine, and starts The external gear that the part of machine blade connection is made for exotic material, the external gear is nibbled with the internal gear at engine blade center Close.

4. test device as claimed in claim 1, it is characterised in that the observation window is two high quartz glass observations Window, two high-speed cameras shoot through two observation windows to engine blade respectively.

5. test device as claimed in claim 1, it is characterised in that the temperature feedback system is anti-for the temperature of closed-loop control Feedback system, its temperature-measuring part is thermocouple temperature measuring apparatus.

6. test device as claimed in claim 1, it is characterised in that the heater box periphery of inner wall is provided with and prevents inwall from receiving To the protection device clashed into.

7. the dynamic oxidation ablation method of testing of a kind of simulated engine blade Service Environment, using any institute of claim 1~6 The dynamic oxidation ablation test device of the simulated engine blade Service Environment stated is tested, and is comprised the following steps：

1) engine blade to be measured is installed in high speed rotating unit, before ablation test, by two high-speed cameras Two images of engine blade under normal temperature are shot through observation window, as not deformed initial pictures；

2) start test, the service temperature of engine blade will be heated to inside heater box, and open high speed rotating unit, make hair Motivation blade rotational speed reaches rotating speed during military service, while two high-speed cameras proceed by captured in real-time, stops after a period of time Only shoot；

3) the engine blade image for shooting the diverse location for obtaining is moved to by identical by the operation matrix of rigid body displacement Position, eliminates rigid body displacement；

4) the engine blade image photographed to test process using Digital Image Correlation Method is contrasted with initial pictures Analyzing and processing, is calculated the ess-strain after engine blade ablation, and engine blade environment lower surface burns under arms Lose the dynamic process for developing.

8. method of testing as claimed in claim 7, it is characterised in that step 3) image selected by feature identification technique Engine blade, and high-speed camera is shot into the engine blade image rotation that obtains to same position using matrix operation.

9. method of testing as claimed in claim 7, it is characterised in that step 4) first shot for every high-speed camera one Group image, is analyzed to the ablation pattern of test process by Digital Image Correlation Method with initial pictures：First will Every image is accordingly divided into some sub-districts, has a gray value f for the every bit (x, y) in the initial pictures before deformation (x, y), the every bit (x ', y ') in the ablation pattern after deformation has a new gray value g (x ', y '), for every height Area calculates following correlation function：

$C_{f,g}\left(\stackrel{\→}{p}\right)=\frac{\underset{x=-M}{\overset{M}{\Σ}}\underset{y=-M}{\overset{M}{\Σ}}\[f(x,y)-f_m\]\×\[g(x^{\′},y^{\′})-g_m\]}{\sqrt{\underset{x=-M}{\overset{M}{\Σ}}\underset{y=-M}{\overset{M}{\Σ}}{\[f(x,y)-f_m\]}^2}\sqrt{\underset{x=-M}{\overset{M}{\Σ}}\underset{y=-M}{\overset{M}{\Σ}}{\[g(x^{\′},y^{\′})-g_m\]}^2}}$

Wherein (x, y) represents the coordinate before deformation, and (x ', y ') represents the coordinate after deformation, and M represents selected image subsection width Half, f (x, y) represent deformation before gray value function, g (x ', y ') represent deformation after gray value function, f_mRepresent deformation Preceding average gray value, g_mThe average gray value after deformation is represented,Wherein u, v are represented respectively Horizontally and vertically direction displacement,Correlation function is represented, by pair correlation functionExtreme value is sought, can be tried to achieve every The displacement (u, v) of a bit；Three-dimensional measurement is realized by two video cameras；Then strain field (ε is calculated by displacement field_x,ε_y, γ_xy)；Stress field can be calculated further according to below equation：

${\mathrm{\σ}}_x=\frac{E}{1-{\mathrm{\μ}}^2}({\mathrm{\ϵ}}_x+{\mathrm{\μ\ϵ}}_y)$

${\mathrm{\σ}}_y=\frac{E}{1-{\mathrm{\μ}}^2}({\mathrm{\ϵ}}_y+{\mathrm{\μ\ϵ}}_x)$

${\mathrm{\τ}}_{xy}=\frac{E}{2(1+\mathrm{\μ})}{\mathrm{\γ}}_{xy}$

Wherein E is the elastic modelling quantity of test material, and μ is material Poisson's ratio.

10. method of testing as claimed in claim 9, it is characterised in that step 4) in pass through local least square method fitting theory Strain field (ε is calculated by displacement field_x,ε_y,γ_xy)。