Thermoacoustic Vibration Test Method and Test Device for Combustion Chamber Splash Guard

Abstract

The present disclosure relates to a method and an experimental device for thermoacoustic vibration testing of a combustion chamber splash guard. The method for thermoacoustic vibration testing of a combustion chamber splash guard includes: at a first temperature, establishing functions of the normal-incidence pulsating pressure load and the grazing-incidence pulsating pressure load respectively with respect to the strain of the splash guard at the first temperature, namely a first function and a second function; at a second temperature, establishing a function of the grazing-incidence pulsating pressure load with respect to the grazing-incidence splash guard strain at the second temperature, namely a third function; based on the first function and the second function, establishing a functional relationship between the normal-incidence strain and the grazing-incidence strain of the splash guard under the same normal-incidence and grazing-incidence pulsating pressure loads at the first temperature, namely a fourth function; based on the third function and the fourth function, establishing a function of the normal-incidence pulsating pressure load with respect to the strain of the splash guard at the second temperature, namely a fifth function; according to the failure strain of the splash guard, calculating and obtaining the pulsating pressure limit value of the splash guard based on the fifth function.

Description

Technical Field

[0001] The present disclosure relates to a method and an apparatus for a thermoacoustic vibration test of a combustion chamber splash plate. Background Art

[0002] The statements herein only provide background information related to the present disclosure and do not necessarily constitute prior art.

[0003] With the development of aeroengine combustion chambers towards high temperature, high pressure, high efficiency, and low emissions, advanced combustion chambers are prone to high-intensity oscillatory combustion compared with conventional combustion chambers due to technologies such as strong swirl, main combustion hole jet, and lean premixed combustion adopted in the design. The splash plate of the aeroengine combustion chamber is located at the head of the flame tube and directly contacts the combustion flame. The metal temperature can reach 900 °C. The pneumatic pressure pulsation generated by combustion oscillation will directly act on the splash plate in the form of an alternating load, triggering its vibration fatigue failure. This kind of structural damage caused by oscillatory combustion is called thermoacoustic fatigue.

[0004] Currently, the research on thermoacoustic fatigue analysis methods at home and abroad has not been in-depth, and there is no accurate, complete, and effective theoretical prediction and analysis method. In this context, conducting a thermoacoustic vibration test of the combustion chamber, measuring the response of the combustion chamber splash plate structure under the action of pneumatic pressure pulsation load, and predicting its possible failure positions and failure modes have become relatively effective methods in engineering.

[0005] As Figure 1 and Figure 2 shown, the splash plate 1 of the combustion chamber is welded to the head adapter section 2 by brazing. The hot side B of the splash plate 1 faces the combustion flame, and the pulsating pressure generated by combustion oscillation directly acts on the surface of the splash plate 1, easily triggering its vibration fatigue failure. When the splash plate vibrates, the high stress is located at the root of the large flanging fillet on the cold side C. Due to the limitation of the installation space position (the gap is about 2 mm) between the splash plate 1 and the head adapter section 2, it is difficult to arrange a dynamic strain measurement structure to respond. Summary of the Invention

[0006] One technical problem to be solved by the present disclosure is to provide a method and an apparatus for a thermoacoustic vibration test of a combustion chamber splash plate, which can obtain the pulsating pressure limit value of the splash plate, and during the engine test, monitor in real time whether the combustion pulsating pressure exceeds the limit, so as to ensure the structural safety of the combustion chamber.

[0007] According to some embodiments of the present disclosure, a method for a thermoacoustic vibration test of a combustion chamber splash plate includes:

[0008] At the first temperature, the splash guard is acoustically excited in the traveling wave tube at normal incidence, the pulsating pressure load and the strain of the splash guard are collected, and a function of the normal incidence pulsating pressure load and the normal incidence splash guard strain at the first temperature is established, that is, the first function; Normal incidence means that the incident direction of the sound wave in the traveling wave tube is perpendicular to the plane flange of the splash guard.

[0009] At the first temperature, the splash guard is acoustically excited in the traveling wave tube at grazing incidence, the pulsating pressure load and the strain of the splash guard are collected, and a function of the grazing incidence pulsating pressure load and the grazing incidence splash guard strain at the first temperature is established, that is, the second function; Grazing incidence means that the incident direction of the sound wave in the traveling wave tube is parallel to the plane flange of the splash guard.

[0010] At the second temperature, the splash guard is acoustically excited in the traveling wave tube at grazing incidence, the pulsating pressure load and the strain of the splash guard are collected, and a function of the grazing incidence pulsating pressure load and the grazing incidence splash guard strain at the second temperature is established, that is, the third function.

[0011] Based on the first function and the second function, a functional relationship between the normal incidence strain and the grazing incidence strain of the splash guard under the same pulsating pressure load at the first temperature is established, and this relationship still holds at the second temperature, that is, the normal incidence - grazing incidence strain relationship function, that is, the fourth function.

[0012] Based on the third function and the fourth function, a function of the normal incidence pulsating pressure load and the strain of the splash guard at the second temperature is established, that is, the fifth function.

[0013] According to the failure strain of the splash guard, based on the fifth function, the pulsating pressure limit value of the splash guard is calculated.

[0014] Wherein, the second temperature is greater than the first temperature.

[0015] In some embodiments, the first temperature is 10 - 30 °C; the second temperature is 700 - 1000 °C.

[0016] In some embodiments, the splash guard includes a plane flange, a ring flange is provided on the plane flange, at least part of the edge of the plane flange has a flanging structure, the flanging structure includes a large flanging and a small flanging, and the strain of the splash guard is the strain on the cold side of the large flanging.

[0017] In some embodiments, the pulsating pressure p generated by the sound pressure level load Lp of the acoustic excitation is converted by the following formula:

[0018]

[0019] Wherein, L p —Sound pressure level load, unit dB; p—Pulsating pressure, unit Pa; p0—Reference sound pressure, which is 2*10- in air5 Pa.

[0020] A combustion chamber splash guard thermoacoustic vibration test device provided according to some embodiments of the present disclosure, for implementing the foregoing combustion chamber splash guard thermoacoustic vibration test method, includes: a traveling wave tube, including a front transition section, a middle test section, and a rear silencing section; a splash guard test piece assembly disposed in the middle test section, which includes a splash guard test piece having a planar flange; an electric air loudspeaker configured to: emit sound waves, and the sound waves enter the middle test section through the front transition section to acoustically excite the splash guard test piece; a normal incidence mounting assembly configured to: mount the splash guard test piece assembly in the middle test section and make the planar flange perpendicular to the incident direction of the sound waves; and an oblique incidence mounting assembly configured to: mount the splash guard test piece assembly in the middle test section and make the planar flange parallel to the incident direction of the sound waves; wherein, the normal incidence mounting assembly and the oblique incidence mounting assembly are alternatively disposed in the middle test section.

[0021] In some embodiments, the middle test section is configured as a box-shaped member, and a test section cover plate is detachably provided on the side of the middle test section.

[0022] In some embodiments, the normal incidence mounting assembly includes a normal incidence box body and a normal incidence tooling. The bottom of the normal incidence tooling is fixedly installed on the bottom of the normal incidence box body, and the splash guard test piece assembly is mounted on the normal incidence tooling.

[0023] In some embodiments, the normal incidence mounting assembly further includes a microphone disposed on the normal incidence tooling, configured to measure the sound pressure load value received by the splash guard test piece.

[0024] In some embodiments, the oblique incidence mounting assembly includes an oblique incidence box body, a heat insulation gasket, and a heating mechanism. The heating mechanism is configured to heat the splash guard test piece assembly, and the splash guard test piece assembly is mounted in the oblique incidence box body through the heat insulation gasket.

[0025] In some embodiments, the heating mechanism includes a modular quartz lamp box.

[0026] In some embodiments, a water cooling structure is provided around the oblique incidence box body, and an air cooling structure is provided in the heating mechanism.

[0027] In some embodiments, the splash guard test piece assembly includes a splash guard test piece, a test piece adapter section, and a stiffness simulation ring; the splash guard test piece is welded to the test piece adapter section, the test piece adapter section is fixed to the stiffness simulation ring, and the stiffness simulation ring is a cage structure for simulating the flexible boundary of the splash guard during engine installation.

[0028] In some embodiments, one or more strain gauges are further included. At least part of the edge of the flat flange has a flanging structure, and the flanging structure includes a large flanging and a small flanging. The strain gauge is arranged on the cold side of the large flanging for measuring the strain of the splash guard test piece.

[0029] In some embodiments, nine strain gauges are included, and the nine strain gauges are symmetrically arranged at the middle position on the cold side of the large flanging.

[0030] In some embodiments, an accelerometer and a laser displacement gauge are further included. The accelerometer is arranged at the test piece adapter section for measuring the vibration acceleration of the splash guard test piece. At least part of the edge of the flat flange has a flanging structure, and the flanging structure includes a large flanging and a small flanging. The laser displacement gauge is arranged at the corner point of the large flanging for measuring the vibration displacement of the splash guard test piece.

[0031] In the technical solution of the present disclosure, by measuring the relationship between the pulsating pressure load and the strain of the splash guard under normal temperature and high-temperature grazing incidence, and combining the test results of normal incidence at normal temperature, the relationship between the pulsating pressure load and the strain of the splash guard under high-temperature normal incidence can be converted, and then the pulsating pressure limit value of the splash guard can be obtained. During the engine test, it is possible to monitor in real time whether the combustion pulsating pressure exceeds the limit to ensure the structural safety of the combustion chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 and Figure 2 are respectively schematic diagrams of the installation positions of the splash guard of the aeroengine combustion chamber from different perspectives;

[0034] Figure 3 is a flowchart of the thermoacoustic vibration test method for the splash guard of the combustion chamber of the present disclosure;

[0035] Figure 4 is a schematic structural diagram of some embodiments of the thermoacoustic vibration test device for the splash guard of the combustion chamber of the present disclosure;

[0036] Figures 5 to 7 are respectively schematic structural diagrams of the normal incidence installation assembly of some embodiments of the thermoacoustic vibration test device for the splash guard of the combustion chamber of the present disclosure from different perspectives;

[0037] Figures 8 to 10 are respectively schematic structural diagrams of the grazing incidence installation assembly of some embodiments of the thermoacoustic vibration test device for the splash guard of the combustion chamber of the present disclosure from different perspectives;

[0038] Figures 11 to 13 These are schematic structural diagrams of the splash guard test piece assembly in the thermal-acoustic vibration test device of the combustion chamber of the present disclosure from different perspectives in some embodiments.

[0039] Figure 14 This is a schematic diagram of the position where the strain gauge is arranged on the splash guard test piece in some embodiments of the thermal-acoustic vibration test device of the combustion chamber of the present disclosure.

[0040] Description of Reference Numerals

[0041] 1. Splash guard; 2. Head adapter section; 3. Front transition section; 4. Middle test section; 5. Test section cover plate; 6. Rear diffusion section; 7. Traveling wave tube support; 8. Full-threaded screw rod; 9. Normal incidence mounting assembly; 901. Normal incidence box; 902. Normal incidence tooling; 903. Microphone; 10. Grazing incidence mounting assembly; 101. Grazing incidence box; 102. Quartz lamp box mounting strip; 103. Heating mechanism; 104. Heat insulation washer; 11. Splash guard test piece assembly; 111. Splash guard test piece; 112. Test piece adapter section; 113. Stiffness simulation ring; 114. Small flanging; 115. Large flanging; 116. Laser displacement gauge; 117. Accelerometer; 12. Strain gauge. Detailed Embodiments

[0042] Now, various exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and in no way limits the present disclosure and its application or use. The present disclosure can be implemented in many different forms and is not limited to the embodiments herein. These embodiments are provided to make the present disclosure thorough and complete and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that: Unless otherwise specifically stated, the relative arrangements of components and steps, the components of materials, numerical expressions, and numerical values set forth in these embodiments should be construed as merely exemplary and not as limitations.

[0043] The terms "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are merely used to distinguish different parts. Terms such as "including" or "comprising" mean that the elements before such terms cover the elements listed after such terms and do not exclude the possibility of also covering other elements. Terms such as "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0044] In the present disclosure, when it is described that a specific device is located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device. When it is described that a specific device is connected to other devices, the specific device may be directly connected to the other devices without an intermediate device, or may not be directly connected to the other devices but have an intermediate device.

[0045] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as those, should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense, unless specifically defined as such herein.

[0046] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the specification.

[0047] As Figure 3 shown, a method for thermoacoustic vibration testing of a combustion chamber splash guard according to some embodiments of the present disclosure includes:

[0048] S1 At a first temperature, acoustically excite the splash guard in the traveling wave tube in a normal incidence manner, collect the pulsating pressure load and the strain of the splash guard, and establish a function regarding the normal incidence pulsating pressure load and the normal incidence splash guard strain at the first temperature, that is, the first function, as follows:

[0049] ε1 = f1(p1)

[0050] In the formula, ε1 is the normal incidence strain at the first temperature, with the unit με; p1 is the normal incidence pulsating pressure at the first temperature, with the unit Pa;

[0051] Normal incidence means that the incident direction of the sound wave in the traveling wave tube is perpendicular to the planar flange of the splash guard;

[0052] S2 At the first temperature, acoustically excite the splash guard in the traveling wave tube in a grazing incidence manner, collect the pulsating pressure load and the strain of the splash guard, and establish a function regarding the grazing incidence pulsating pressure load and the grazing incidence splash guard strain at the first temperature, that is, the second function, as follows:

[0053] ε2 = f2(p2)

[0054] In the formula, ε2 is the grazing incidence strain at the first temperature, with the unit με; p2 is the grazing incidence pulsating pressure at the first temperature, with the unit Pa;

[0055] Grazing incidence means that the incident direction of the sound wave in the traveling wave tube is parallel to the planar flange of the splash guard;

[0056] At the second temperature, the splash guard is acoustically excited in the traveling wave tube in a grazing incidence manner, the pulsating pressure load and the strain of the splash guard are collected, and a function of the grazing incidence pulsating pressure load and the grazing incidence splash guard strain at the second temperature is established, that is, the third function, as follows:

[0057] ε3 = f3(p3)

[0058] Where ε3 is the grazing incidence strain at the second temperature, in με; p3 is the grazing incidence pulsating pressure at the second temperature, in Pa;

[0059] Based on the first function and the second function, establish a functional relationship between the normal incidence strain and the grazing incidence strain of the splash guard under the same pulsating pressure load (p1 = p2) at the first temperature, and this relationship still holds at the second temperature, that is, the normal incidence - grazing incidence strain relationship function, that is, the fourth function, as follows:

[0060] ε1 = f4(ε2)

[0061] Based on the third function and the fourth function, establish a function of the normal incidence pulsating pressure load and the strain of the splash guard at the second temperature, that is, the fifth function, as follows:

[0062] ε4 = f4[f3(p4)]

[0063] Where ε4 is the normal incidence strain at the second temperature, in με; p4 is the normal incidence pulsating pressure at the second temperature, in Pa;

[0064] According to the failure strain of the splash guard, based on the fifth function, calculate the pulsating pressure limit value of the splash guard;

[0065] Among them, the second temperature is higher than the first temperature.

[0066] The failure strain ε of the splash guard at the second temperature is measured through a high - cycle fatigue test Lim , substituting it into the fifth function can obtain the pulsating pressure limit value p of the splash guard Lim . During the aero - engine test, by real - time monitoring whether the combustion pulsating pressure p exceeds the limit value p Lim , thus ensuring the safety of the engine.

[0067] In some embodiments, the first temperature is 10 - 30 °C; the second temperature is 700 - 1000 °C, that is to say, the first temperature is normal temperature and the second temperature is high temperature.

[0068] In some embodiments, the splash guard includes a flat flange provided with an annular flange. At least part of the edge of the flat flange has a flanging structure, which includes a large flange and a small flange. The strain of the splash guard is the strain on the cold side of the large flange. When the splash guard vibrates, the high stress is located at the root of the fillet of the cold side of the large flange. Therefore, measuring the strain of the splash guard is the strain on the cold side of the large flange to ensure the measurement accuracy.

[0069] Regarding how to achieve the conversion between the sound pressure level load and the pulsating pressure, in some embodiments, the sound pressure level load L of the acoustic excitation p The generated pulsating pressure p is converted by the following formula:

[0070]

[0071] where, L p —Sound pressure level load, unit dB; p—Pulsating pressure, unit Pa; p0—Reference sound pressure, which is 2×10- 5 Pa in air.

[0072] Combined with Figures 4 to 14 As shown, according to some embodiments of the present disclosure, a thermoacoustic vibration test device for a combustion chamber splash guard is provided to implement the aforementioned thermoacoustic vibration test method for the combustion chamber splash guard, including: a traveling wave tube, a splash guard test piece assembly 11, an electric air loudspeaker (not shown in the figure), a normal incidence mounting assembly 9, and a grazing incidence mounting assembly 10. Among them, the traveling wave tube includes a front transition section 3, a middle test section 4, and a rear diffusion section 6; the splash guard test piece assembly 11 is arranged in the middle test section 4, and it includes a splash guard test piece 111 with a flat flange; the electric air loudspeaker is configured to: emit sound waves, and the sound waves enter the middle test section 4 through the front transition section 3 to perform acoustic excitation on the splash guard test piece 111; the normal incidence mounting assembly 9 is configured to: mount the splash guard test piece assembly 11 in the middle test section 4 and make the flat flange perpendicular to the incident direction of the sound waves; the grazing incidence mounting assembly 10 is configured to: mount the splash guard test piece assembly 11 in the middle test section 4 and make the flat flange parallel to the incident direction of the sound waves; the normal incidence mounting assembly 9 and the grazing incidence mounting assembly 10 are alternatively arranged in the middle test section 4.

[0073] As Figure 4 shown, by designing the thermoacoustic vibration test device for the combustion chamber splash guard, the structural response of the splash guard under the sound pressure load can be measured. After the electric air loudspeaker emits sound waves, they pass through the horn section, enter the front transition section 3, excite the splash guard test piece in the middle test section 4, and then weaken the sound pressure level through the rear diffusion section 6.

[0074] As Figure 4As shown, in some embodiments, the middle test section 4 is configured as a box-shaped member, and a test section cover plate 5 is detachably provided on the side of the middle test section 4 to facilitate the alternative installation of the normal incidence installation assembly 9 and the grazing incidence installation assembly 10 and wire connection. As Figure 4 As shown, in some embodiments, the traveling wave tube further includes a traveling wave tube bracket 7 and a full-threaded screw rod 8. The middle test section 4 is installed on the traveling wave tube bracket 7, and the traveling wave tube bracket 7 is fixedly connected by the full-threaded screw rod 8.

[0075] As Figures 5 to 7 As shown, when performing a normal incidence test, the normal incidence installation assembly 9 installs the splash guard test piece assembly 11 in the middle test section 4; as Figures 8 to 10 As shown, when performing a grazing incidence test, the grazing incidence installation assembly 10 installs the splash guard test piece assembly 11 in the middle test section 4.

[0076] As Figures 5 to 7 As shown, in some embodiments, the normal incidence installation assembly 9 includes a normal incidence box body 901 and a normal incidence tooling 902. The bottom of the normal incidence tooling 902 is fixedly installed on the bottom of the normal incidence box body 901, and the splash guard test piece assembly 11 is installed on the normal incidence tooling 902.

[0077] The acoustic load emitted by the electric air speaker will attenuate after passing through the horn section and the front transition section 3. In some embodiments, as Figure 6 As shown, the normal incidence installation assembly 9 further includes a microphone 903 provided on the normal incidence tooling 902, which is configured to measure the sound pressure load value received by the splash guard test piece 111. The microphone 903 can detect the actual sound pressure load magnitude received by the splash guard test piece 111 in real time.

[0078] Since the splash guard test piece cannot be heated during the normal incidence test, as Figures 8 to 10 As shown, in some embodiments, the grazing incidence installation assembly 10 includes a grazing incidence box body 101, a heat insulation gasket 104, and a heating mechanism 103. The heating mechanism 103 is configured to heat the splash guard test piece assembly 11, and the splash guard test piece assembly 11 is installed in the grazing incidence box body 101 through the heat insulation gasket 104. In some embodiments, the heating mechanism 103 includes a modular quartz lamp box, and the modular quartz lamp box is connected to the grazing incidence box body 101 through a quartz lamp box installation strip 102. The modular quartz lamp box heats quickly and reliably, and has high feasibility.

[0079] Since the test temperature can reach 900 °C, a cooling design needs to be carried out for the grazing incidence installation assembly 10. In some embodiments, a water cooling structure is provided around the grazing incidence box body 101, and an air cooling structure is provided for the heating mechanism 103.

[0080] As Figures 11 to 13 , in combination with Figure 7and Figure 10 As shown in Figure 10 , in some embodiments, the splash guard test piece assembly 11 includes a splash guard test piece 111, a test piece adapter section 112, and a stiffness simulation ring 113; the splash guard test piece 111 is brazed and welded to the test piece adapter section 112, the test piece adapter section 112 is fixedly connected to the stiffness simulation ring 113 by bolts, the stiffness simulation ring 113 is a squirrel cage structure for simulating the flexible boundary of the splash guard during engine installation, and the stiffness simulation ring 113 is connected to the normal incidence installation assembly 9 and the grazing incidence installation assembly 10.

[0081] As Figure 14 As shown in Figure 14 , in some embodiments, the combustion chamber splash guard thermoacoustic vibration test device further includes one or more strain gauges 12. At least part of the edge of the flat flange has a flanging structure, and the flanging structure includes a large flanging 115 and a small flanging 114. The strain gauge 12 is arranged on the cold side of the large flanging 115 for measuring the strain of the splash guard test piece 111. When the splash guard vibrates, the high stress is located at the root of the fillet of the cold side of the large flanging. Therefore, the strain measured for the splash guard is the strain on the cold side of the large flanging to ensure the measurement accuracy.

[0082] As Figure 11 As shown in Figure 11 , in some embodiments, an accelerometer 117 is provided at the test piece adapter section 112 for measuring the vibration acceleration of the test piece; a laser displacement gauge 116 is arranged at the corner point of the large flanging 115 of the splash guard test piece 111 for measuring the vibration displacement of the test piece. In the second temperature grazing incidence test, the measuring point positions of the splash guard test piece assembly 11 are the same as those in the first temperature grazing incidence, except that the accelerometer 117 is a high-temperature accelerometer and the strain gauge 12 is a high-temperature strain gauge.

[0083] As Figure 14 As shown in Figure 14 , in some embodiments, the combustion chamber splash guard thermoacoustic vibration test device includes 9 strain gauges 12, and the 9 strain gauges 12 are symmetrically arranged at the middle position of the cold side of the large flanging 115. Practice has proved that such an arrangement can further improve the strain detection accuracy and has high feasibility.

[0084] So far, the embodiments of the present disclosure have been described in detail. To avoid obscuring the concept of the present disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0085] Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration purposes and not for limiting the scope of the present disclosure. Those skilled in the art should understand that the above embodiments can be modified or some technical features can be equivalently replaced without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A method for thermoacoustic vibration test of a combustion chamber splash guard, comprising: At a first temperature, acoustically exciting the splash guard in a traveling wave tube in a normal incidence manner, collecting the pulsating pressure load and the strain of the splash guard, and establishing a function of the normal incidence pulsating pressure load and the normal incidence splash guard strain at the first temperature, i.e., the first function; the normal incidence means that the incident direction of the sound wave in the traveling wave tube is perpendicular to the plane flange of the splash guard; At a first temperature, acoustically exciting the splash guard in a grazing incidence manner in the traveling wave tube, collecting the pulsating pressure load and the strain of the splash guard, and establishing a function of the grazing incidence pulsating pressure load and the grazing incidence splash guard strain at the first temperature, i.e., the second function; the grazing incidence means that the incident direction of the sound wave in the traveling wave tube is parallel to the plane flange of the splash guard; At a second temperature, acoustically exciting the splash guard in a grazing incidence manner in the traveling wave tube, collecting the pulsating pressure load and the strain of the splash guard, and establishing a function of the grazing incidence pulsating pressure load and the grazing incidence splash guard strain at the second temperature, i.e., the third function; Based on the first function and the second function, establish a functional relationship between the normal incidence strain - grazing incidence strain of the splash guard under the same pulsating pressure load of normal incidence and grazing incidence at the first temperature, and this relationship still holds at the second temperature, i.e., the normal incidence - grazing incidence strain relationship function, i.e., the fourth function; Based on the third function and the fourth function, establish a function of the normal incidence pulsating pressure load and the strain of the splash guard at the second temperature, i.e., the fifth function; According to the failure strain of the splash guard, calculate the pulsating pressure limit value of the splash guard based on the fifth function; Wherein, the second temperature is greater than the first temperature.

2. The hot acoustic vibration test method for the combustion chamber splash guard according to claim 1, wherein, The first temperature is 10 - 30 °C; the second temperature is 700 - 1000 °C.

3. The hot acoustic vibration test method for the combustion chamber splash guard according to claim 1, wherein, The splash guard includes a plane flange, an annular flange is provided on the plane flange, at least part of the edge of the plane flange has a flanging structure, the flanging structure includes a large flanging and a small flanging, and the strain of the splash guard is the strain on the cold side of the large flanging.

4. The method for the thermoacoustic vibration test of the combustion chamber splash guard according to claim 1, wherein, The pulsating pressure p generated by the sound pressure level load Lp of the acoustic excitation is converted by the following formula: Among them, L p - Sound pressure level load, unit dB; p - Pulsating pressure, unit Pa; p0 - Reference sound pressure, which is 2 * 10 - 5 Pa in air.

5. A combustion chamber splash guard thermoacoustic vibration test device for implementing the combustion chamber splash guard thermoacoustic vibration test method described in claim 1, characterized in that, Including: A traveling wave tube, including a front transition section (3), a middle test section (4), and a rear diffusion section (6); A splash guard test piece assembly (11), arranged in the middle test section (4), and it includes a splash guard test piece (111) with a plane flange; An electric air loudspeaker, configured to: emit sound waves, and the sound waves enter the middle test section (4) through the front transition section (3) to acoustically excite the splash guard test piece (111); A normal incidence mounting assembly (9), configured to: mount the splash guard test piece assembly (11) in the middle test section (4), and make the plane flange perpendicular to the incident direction of the sound wave; and A grazing incidence mounting assembly (10), configured to: mount the splash guard test piece assembly (11) in the middle test section (4), and make the plane flange parallel to the incident direction of the sound wave; Wherein, the normal incidence mounting assembly (9) and the grazing incidence mounting assembly (10) are alternatively arranged in the middle test section (4).

6. The combustion chamber splash guard thermoacoustic vibration test device according to claim 5, characterized in that The central test section (4) is configured as a box-shaped member, and a test section cover plate (5) is detachably provided on the side of the central test section (4).

7. The combustion chamber splash guard thermoacoustic vibration test device according to claim 5, characterized in that, The normal incidence mounting assembly (9) includes a normal incidence box body (901) and a normal incidence tooling (902). The bottom of the normal incidence tooling (902) is fixedly installed on the bottom of the normal incidence box body (901), and the splash guard test piece assembly (11) is installed on the normal incidence tooling (902).

8. The combustion chamber splash guard hot acoustic vibration test device according to claim 7, characterized in that, The normal incidence mounting assembly (9) further includes a microphone (903) provided on the normal incidence tooling (902), which is configured to measure the sound pressure load value received by the splash guard test piece (111).

9. The combustion chamber splash guard hot acoustic vibration test device according to claim 5, wherein, The grazing incidence mounting assembly (10) includes a grazing incidence box body (101), a heat insulation gasket (104), and a heating mechanism (103). The heating mechanism (103) is configured to heat the splash guard test piece assembly (11), and the splash guard test piece assembly (11) is installed in the grazing incidence box body (101) through the heat insulation gasket (104).

10. The combustion chamber splash guard thermoacoustic vibration test device according to claim 9, characterized in that, The heating mechanism (103) includes a modular quartz lamp box.

11. The combustion chamber splash guard hot acoustic vibration test device according to claim 9, characterized in that, A water cooling structure is provided around the grazing incidence box body (101), and an air cooling structure is provided for the heating mechanism (103).

12. The combustion chamber splash guard thermoacoustic vibration test device according to claim 5, characterized in that The splash guard test piece assembly (11) includes a splash guard test piece (111), a test piece adapter section (112), and a stiffness simulation ring (113). The splash guard test piece (111) is welded to the test piece adapter section (112), the test piece adapter section (112) is fixed to the stiffness simulation ring (113), and the stiffness simulation ring (113) is a squirrel cage structure for simulating the flexible boundary of the splash guard during engine installation.

13. The combustion chamber splash guard hot acoustic vibration test device according to claim 5, characterized in that One or more strain gauges (12) are further included. At least part of the edge of the flat flange has a flanging structure, and the flanging structure includes a large flange (115) and a small flange (114). The strain gauge (12) is arranged on the cold side of the large flange (115) for measuring the strain of the splash guard test piece (111).

14. The combustion chamber splash guard thermoacoustic vibration test device according to claim 13, wherein Nine of the strain gauges (12) are included, and the nine strain gauges (12) are symmetrically arranged at the middle position on the cold side of the large flange (115).

15. The combustion chamber splash guard hot acoustic vibration test device according to claim 12, characterized in that, An accelerometer (117) and a laser displacement gauge (116) are further included. The accelerometer (117) is arranged on the test piece adapter section (112) for measuring the vibration acceleration of the splash guard test piece (111). At least part of the edge of the flat flange has a flanging structure, and the flanging structure includes a large flange (115) and a small flange (114). The laser displacement gauge (116) is arranged at the corner point of the large flange (115) for measuring the vibration displacement of the splash guard test piece (111).

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