Auxiliary power and engine combined debugging device in test cabin and design method

Abstract

The application provides a kind of auxiliary power and engine combined debugging device and design method in test chamber, and the auxiliary power and engine combined debugging device in test chamber includes: support platform, box is provided, auxiliary power device is arranged in the inner chamber of box;Air inlet pipeline, the inlet end of air inlet pipeline is connected with altitude table air inlet pipeline mixer, the outlet end of air inlet pipeline is connected with the air inlet of auxiliary power device in the inner chamber of box;Exhaust pipeline, the inlet end of exhaust pipeline is connected with the air inlet of auxiliary power device in the inner chamber of box, and the outlet end of exhaust pipeline is connected with altitude chamber exhaust diffuser.Connecting with altitude table air inlet pipeline mixer through the design of air from the rear, the calculated pipeline parameter ensures that auxiliary power device obtains the inlet condition consistent with main engine, and steady-state simulation accuracy reaches pressure unevenness less than 1%, temperature unevenness less than 1%.

Description

Technical Field

[0001] This invention relates to the field of high-altitude simulation testing technology for aero-engines, specifically to a device and design method for joint debugging of auxiliary power and engine in a test chamber. Background Technology

[0002] High-altitude simulation testing of aero-engines is the most effective means of exploring and evaluating performance and operating characteristics across the entire working envelope during engine development. The high-altitude test bench (referred to as "high-altitude test bench"), as an important piece of equipment for aero-engine whole-engine testing, can simulate the intake and exhaust conditions of an engine during flight and plays a role in the evaluation and assessment process of the engine.

[0003] With the development of aviation technology, modern aircraft are usually equipped with auxiliary power units (such as APUs and emergency power units) in addition to their main engines. These units work in conjunction with the main engines during actual flight, sharing the same flight environment conditions. However, in current high-altitude simulation tests, auxiliary power units often cannot obtain the same simulated environmental conditions as the main engines, resulting in test results that do not accurately reflect their performance characteristics under real flight conditions.

[0004] Traditional testing methods for auxiliary power units have the following technical drawbacks:

[0005] It is not possible to provide the auxiliary power unit with the same high-altitude environmental simulation conditions as the main engine during the test;

[0006] The lack of joint testing capabilities with the main engine makes it difficult to assess the interaction between the two in high-altitude environments.

[0007] The test system lacks an intake design method for auxiliary power devices, and the control methods for key intake parameters such as pressure and temperature are unclear.

[0008] An inadequate exhaust treatment system may affect the testing environment of the main engine. Summary of the Invention

[0009] In view of this, the present invention provides a device and design method for joint debugging of auxiliary power and engine in test chamber, so as to enable the auxiliary power unit to obtain the same simulated inlet conditions as the engine when conducting direct-drive high-altitude simulation test together with the engine, and realize the joint test of the two in real flight environment.

[0010] The present invention provides the following technical solution: a device for joint debugging of auxiliary power and engine in a test chamber, comprising: a support platform, a housing, wherein an auxiliary power unit is disposed in the inner cavity of the housing; an intake pipe, wherein the inlet end of the intake pipe is connected to the intake pipe mixer of the high-altitude test chamber, and the outlet end of the intake pipe is connected to the intake port of the auxiliary power unit in the inner cavity of the housing; and an exhaust pipe, wherein the inlet end of the exhaust pipe is connected to the intake port of the auxiliary power unit in the inner cavity of the housing, and the outlet end of the exhaust pipe is connected to the exhaust diffuser of the high-altitude test chamber.

[0011] A design method for a test apparatus for joint commissioning of an auxiliary power unit and an engine within a test chamber, comprising:

[0012] Step 1: Determine the inner diameter of the inlet flow measurement section based on the air intake method of the auxiliary power unit;

[0013] Step 2: Design the shape of the contraction segment using a segmented double-twist line design method;

[0014] Step 3: Design the inner diameter of the tooth section based on the tooth gap;

[0015] Step 4: Select the inner diameter of the forecourt intake section and determine the design parameters of the forecourt intake section based on the mass flow rate.

[0016] Compared with the prior art, the beneficial effects that the at least one technical solution adopted by the present invention can achieve include at least the following:

[0017] High simulation accuracy: By designing the intake air from the mixer in the high-altitude test chamber, the calculated pipeline parameters ensure that the auxiliary power unit obtains the same inlet conditions as the main engine, and the steady-state simulation accuracy reaches less than 1% for pressure non-uniformity and less than 1% for temperature non-uniformity.

[0018] Improved testing efficiency: The system enables simultaneous testing of the auxiliary power unit and the main engine, avoiding the time and economic costs associated with separate testing, and improving testing efficiency by more than 40%.

[0019] High safety and reliability: The fully enclosed shell design and integrated safety control system can effectively control test risks and ensure the safety of equipment and personnel.

[0020] High adaptability: The modular auxiliary power unit installation platform design can be adapted to various models of auxiliary power units, improving the equipment's versatility and utilization rate.

[0021] Comprehensive and accurate data: The sophisticated measurement and data acquisition systems can comprehensively record the performance parameters of the auxiliary power unit in high-altitude environments, providing a reliable basis for product research and development and improvement. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the intake pipe structure and test layout;

[0025] Figure 3 This is a flowchart illustrating an embodiment of the present invention.

[0026] Reference numerals in the attached diagram: 1. Intake pipe; 2. Housing; 3. Support platform; 4. Exhaust pipe; 14. Grate sealing section; 15. Straight guide section; 16. Intake section. Detailed Implementation

[0027] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a device for joint debugging of auxiliary power and engine in a test chamber, including an intake pipe 1, an exhaust pipe 4, a support platform 3, and a housing 2. The support platform 3 is provided with the housing 2, and the auxiliary power unit is arranged in the inner cavity of the housing 2; the inlet end of the intake pipe 1 is connected to the high-altitude test chamber intake pipe mixer, and the outlet end of the intake pipe 1 is connected to the air inlet of the auxiliary power unit in the inner cavity of the housing 2; the inlet end of the exhaust pipe 4 is connected to the air inlet of the auxiliary power unit in the inner cavity of the housing 2, and the outlet end of the exhaust pipe 4 is connected to the high-altitude test chamber exhaust diffuser.

[0030] The air intake pipe 1, along the gas flow direction, sequentially includes: an intake section 16, a flow guiding straight section 15, and a toothed sealing section 14. The intake section 16 is connected to the mixer in the high-altitude test intake pipe. The flow guiding straight section 15 is provided with a tapered guide section and a straight section for flow stabilization (not shown in the figure, located between the tapered guide section and the toothed sealing section 14). The large-diameter end of the guide section is connected to the outlet of the intake section 16, and the small-diameter end is connected to the inlet of the straight section. The toothed sealing section 14 is connected to the outlet of the straight section, and its inner wall is provided with a toothed structure for sealing. The inlet measuring section is connected to the toothed sealing section 14. When the auxiliary power unit and the engine are jointly tested in the test chamber, the auxiliary power unit is installed on the support platform 3 inside the shell. The auxiliary power unit is supplied with gas at the same temperature and pressure as the engine through the intake pipe 1, which is branched from the main air supply pipe of the test chamber, so that the intake conditions are consistent with those of the engine. The high-temperature exhaust gas discharged by the auxiliary power unit and the gas inside the shell are discharged into the high-altitude chamber exhaust diffuser through the exhaust pipe 4 via the ejector and the high-altitude test exhaust unit.

[0031] The intake pipe 1 is led out from the direct-connection high-altitude test intake pipe mixer and is made of stainless steel.

[0032] The intake section 16 is connected to the high-altitude test intake pipeline mixer. A high-precision regulating valve is installed on the intake section 16. The high-precision regulating valve is an electric butterfly valve with a response time of less than 0.5 seconds and a control accuracy of ±1%FS.

[0033] The straight section 15 is equipped with a tapered flow guide structure and a steady flow straight section. The tapered flow guide structure adopts a segmented double twist line design. The straight section is required to be no less than 3 times the diameter of the engine inlet. The large end of the tapered flow guide structure is connected to the intake section 16, and the small end of the tapered flow guide structure is connected to the steady flow straight section.

[0034] It should be noted that, Figure 1 The middle arrow indicates the direction of airflow intake.

[0035] like Figure 3 As shown, this embodiment of the invention provides a design method for a test device for joint debugging of an auxiliary power unit and an engine in a test chamber, specifically including the following steps:

[0036] Step 1: Determine the inner diameter of the inlet flow measurement section based on the air intake method of the auxiliary power unit;

[0037] Step 2: Design the shape of the contraction segment using a segmented double-twist line design method;

[0038] Step 3: Design the inner diameter of the tooth section based on the tooth gap;

[0039] Step 4: Select the inner diameter of the forecourt intake section and determine the design parameters of the forecourt intake section based on the mass flow rate.

[0040] The design method for the inlet flow measurement section is as follows:

[0041] If the auxiliary power unit has axial air intake, the inner diameter of the inlet flow measurement section is the same as the inner diameter of the auxiliary power unit, that is:

[0042] (1)

[0043] in:

[0044] D in The inner diameter of the inlet flow measurement section;

[0045] D is the inner diameter of the auxiliary power unit;

[0046] If the auxiliary power unit has non-axial air intake, the intake flow measurement section pipeline should be designed according to the flow level to ensure that the Mach number Ma in the designed flow pipe is not greater than 0.5, providing a favorable measurement environment for total temperature and total pressure. Typically, the design is performed using a standard atmospheric sea-level static state as the standard, and the calculation method is as follows:

[0047] The length L of the inlet flow measurement section, starting from the total temperature and total pressure measurement section, extends downstream to the auxiliary power unit with a length ≥ 1D. in Its upstream connection to the contraction section has a length ≥1.5D. in ,Right now

[0048] (2)

[0049] Calculate the minimum inner diameter D of the inlet flow measurement section based on the Mach number Ma in the design flow tube. in,min The method is as follows:

[0050] (3)

[0051] in:

[0052] W represents the maximum airflow rate of the auxiliary power unit under standard conditions;

[0053] ρ is the air density under standard conditions, and the corresponding operating condition value can also be obtained by looking up a table according to the actual situation.

[0054] Ma is the Mach number in the design flow tube, typically 0.4 to 0.5;

[0055] γ is the specific heat ratio of air, which is usually taken as 1.4. For other operating conditions, it is necessary to refer to the air thermodynamic property table to obtain it.

[0056] R is the gas constant, which is 287 J / (kg·K) for air.

[0057] T represents the gas temperature, which is 288.15K under standard conditions and can be adjusted according to operating conditions.

[0058] π is the mathematical constant pi.

[0059] Calculate D in this way in,min After that, it is generally directly taken as D. in Process the flow measurement end, i.e., D in equation (2). in =D in,min Alternatively, standard parts with similar inner diameters can be selected based on the specifications of the seamless metal tube. The selection principle is to take the larger inner diameter of the standard tube as D. in If the non-calculated inner diameter is used, the true Mach number Ma is checked according to the following formula. r The deviation from the design Mach number is no greater than 0.05.

[0060] (4)

[0061] The principle for selecting pipe wall thickness n is: D in When the diameter is <500mm, take 3-5mm, D in For lengths ≥500mm, use 8mm.

[0062] To calculate the pressure loss coefficient λ, it is first necessary to calculate the Reynolds number Re of the inlet flow measurement section for this pipe diameter. The calculation method is as follows:

[0063] (5)

[0064] in:

[0065] μ is the gas dynamic viscosity coefficient, which is generally taken as 1.82×10⁻⁵ Pa·s;

[0066] The pressure loss coefficient λ is calculated based on the range of values ​​for the Reynolds number, using the following method:

[0067] (6)

[0068] in:

[0069] ε represents the absolute roughness of the inner wall surface of the pipe;

[0070] The pressure loss coefficient λ is calculated based on equation (5), and the inner diameter D of the inlet flow measurement section is calculated based on equation (3). in The length L of the inlet flow measurement section is calculated using equation (2). The friction loss ΔP of the inlet flow measurement section can be obtained using the following formula:

[0071] (7)

[0072] Calculate the friction loss along the inlet flow measurement section. If it does not exceed 1%, the system can be put into use. If it exceeds 1%, adjustments can be made by reducing the design Mach number Ma in the flow pipe (not recommended to be below 0.1) or reducing the absolute roughness ε of the pipe inner wall. Note that when using standard parts in the calculation, Ma should be Ma. r D in It should be the inner diameter of the standard pipe fitting.

[0073] Measurement point distribution method

[0074] The inlet flow measurement section is equipped with three circumferentially distributed total pressure measuring points, three static pressure measuring points, and three total temperature measuring points. The distance between the measuring sections of the total pressure, total temperature, and static pressure measuring points is 10% of the pipe diameter. The measuring points at each section do not interfere with each other. There is an angle difference in the circumferential distribution. The total pressure measuring point is located at a distance of 1 D from the engine inlet. in .

[0075] The design method for the contraction section is as follows:

[0076] The contraction section is a transition section connecting the inlet flow measurement section and the pre-chamber air intake section. The surface of the contraction section adopts a segmented double-twist design, and the calculation formulas are as shown in equations (8) to (12), where the large end connects to the air intake section and the small end connects to the grate sealing section;

[0077] (8)

[0078]

[0079] (10)

[0080] (11)

[0081] (12)

[0082] In the formula,

[0083] x is the axial dimension of the contracted section surface;

[0084] y is the radial dimension of the contracted section surface;

[0085] r1 is the radius of the larger end of the contraction segment, and its value is D. f / 2,D f The diameter of the large end of the contraction section;

[0086] r2 is the radius of the smaller end of the contraction segment;

[0087] l c This is the total length of the contraction segment, usually taken as 2D. in To 3D in ;

[0088] xi The axial dimension of the inflection point of the segmented double-twist line;

[0089] The contraction rate of the first segment of the contraction segment;

[0090] The contraction rate of the latter part of the contraction segment;

[0091] k is the inflection point coefficient, with a value ranging from 0.3 to 0.35.

[0092] Design method for the sealing section of the toothed comb:

[0093] The gap between the teeth of the grate sealing section is designed to be 1-2 mm. The calculation method for the gap between the teeth is shown in formula (13). The number of teeth is not less than 10, and the angle of the teeth is usually 30°.

[0094] (13)

[0095] in, For the gap between the teeth, The inner diameter of the comb tooth section. To measure the outer diameter of the section, and , where n' is the wall thickness of the inlet flow measurement section.

[0096] Design method for the air intake section of the front chamber:

[0097] The piping from the forecourt to the vicinity of the auxiliary power unit inlet is typically quite long. Considering the stability of the auxiliary power unit's intake pressure, the forecourt intake section should also have a certain pressure-stabilizing function. Therefore, D f Usually greater than D in Select D f Afterwards, similar to the inlet measurement section, the pressure drop per 100 meters should be checked according to equations (14) to (17). Note that during the calculation process, the maximum air flow rate W of the auxiliary power unit under standard conditions is considered to be continuous and constant, and the gas adopts an ideal gas model.

[0098] (14)

[0099] (15)

[0100] (16)

[0101] (17)

[0102] in,

[0103] This refers to the pressure loss along the intake section of the anterior chamber;

[0104] v fThe air velocity in the anterior chamber intake section;

[0105] Re f The Reynolds number is the number of airflow in the anterior chamber intake section.

[0106] λ i This is the pressure loss coefficient introduced by roughness;

[0107] ε f The absolute roughness of the ductwork in the air intake section of the anterior chamber;

[0108] λ j The pressure loss coefficient introduced for pipeline elbows is taken as 0.3~2 depending on the elbow type, where n is the number of elbows;

[0109] λ k The pressure loss coefficient of the pipeline valves is determined according to the valve type, and m is the number of pipeline valves;

[0110] L f This refers to the length of the duct in the anterior chamber air intake section;

[0111] The outlet pressure of a typical mixer is about 110 kPa to 130 kPa. When the inlet section of the pre-chamber reaches the large end of the contraction section, the pressure drop should be controlled at around 10 kPa. If the pressure drop is too large, the pipeline design should be adjusted, taking into account measures such as reducing the length, reducing the number of bends, and increasing the pipe diameter.

[0112] The shell is a fully enclosed structure made of stainless steel, capable of withstanding pressure loads and temperature changes in a high-altitude simulated environment. The shell consists of a left shell, a right shell, and a mounting platform base, with the contact surfaces sealed by gaskets. The shell is equipped with an intake pipe connection hole, an exhaust pipe connection hole, an engine bleed air interface, a cable threading hole, and an observation window, facilitating connection to intake and exhaust pipes and the engine, as well as auxiliary power unit cable connections and maintenance. The shell has a static pressure measurement interface, enabling real-time monitoring of the internal pressure. By adjusting the intake valve, the pressure is maintained at approximately the same level as the pressure inside the high-altitude test chamber, preventing stress deformation caused by excessive pressure differences. The shell and auxiliary power unit mounting platform are integrated, taking into account the installation and connection requirements of various auxiliary power unit accessories while ensuring structural strength and sealing.

[0113] The auxiliary power unit installation platform adopts a modular design concept, and the position of the installation adjustment mechanism can be adjusted to adapt to different models of auxiliary power units; the platform is equipped with a multi-dimensional adjustment mechanism to achieve precise positioning of the auxiliary power unit installation position; and it adopts a mounting base with a shock-resistant and reinforced structure to reduce the vibration impact on the auxiliary power unit.

[0114] The exhaust pipe is made of high-temperature resistant material, which can withstand the high-temperature exhaust gas discharged from the auxiliary power unit; the pipe is designed with an airflow guiding device to ensure smooth exhaust and reduce pressure loss; the exhaust pipe is connected to the direct-connection high-altitude platform exhaust diffuser, and the exhaust is uniformly drawn by the extraction unit; temperature and pressure monitoring points are set in the pipe to monitor the exhaust status in real time.

[0115] The control system communicates in real time with the main control system of the high-altitude test platform to ensure the synchronization of test parameters; it has a safety switching function that automatically activates protective measures in abnormal situations, switching to in-cabin air intake or atmospheric dual-flow air intake; and it integrates a high-altitude chamber data acquisition system to record all key parameters during the test.

[0116] The following description uses a specific embodiment as an example:

[0117] Inlet Measurement Section: This example uses a circumferential intake auxiliary power device, so it is necessary to calculate and design the inlet measurement section. Ma is set to 0.5, W to 3.5 kg / s, and a seamless stainless steel metal pipe is used with an absolute roughness of 0.2 mm. The selected working condition is standard atmospheric sea level (pressure 101.325 kPa, temperature 15℃ air). The calculated density is 1.225 kg / m3, and the dynamic viscosity coefficient is 1.82 × 10⁻⁵ Pa·s. An ideal gas model is used for calculation, with γ = 1.4 and R = 287 J / (kg·K). Substituting the parameters into equations (2) to (7) yields the following results:

[0118] In this example, the inner diameter of the pipe is calculated by measuring the inlet section using a non-standard machining process. Therefore:

[0119]

[0120]

[0121] n' is designed to be 3mm.

[0122] Calculate Re to get:

[0123]

[0124] Therefore, the flow regime is turbulent. Thus, the method for calculating λ is as follows: solving for the implicit function yields:

[0125]

[0126] According to formula (7), ΔP can be calculated:

[0127]

[0128] The pressure after loss, calculated from the inlet section of the anterior chamber, is 120 - 9.36 = 110.64 kPa. The calculated loss ratio is 0.947 / 110.64 = 0.0086, which is approximately 0.86%, less than 1%. Therefore, using a straight pipe section with an inner diameter of 146 mm and a length of 366 mm as the inlet flow measurement section is reasonable. At this time, the distance between the total pressure measurement section and the exhaust end of the inlet flow measurement section is 146 mm, and the spacing between the total pressure measurement section, the total temperature measurement section, and the static pressure measurement section is not less than 14.6 mm.

[0129] Contraction section: The inner surface of the contraction section is calculated according to formulas (8) to (12), where:

[0130]

[0131]

[0132]

[0133] Taking the inflection point coefficient k as 0.35, the following calculations were performed:

[0134]

[0135] Calculate the value of α, and we get:

[0136]

[0137] Calculate the value of β to get:

[0138]

[0139] The calculated r1 and x i Substituting α and β into equations (8) and (9) respectively, we obtain x∈(0, x... i ) and x∈(x i , l c The curve in the interval is selected with the same wall thickness as the inlet measurement section.

[0140] Anterior chamber air intake section: Connects to the high-altitude test platform air intake mixing unit. In this example, the inlet pressure of the air intake section is 120 kPa. f The length is 450mm, W is 3.5kg / s, and L is... f The pipeline is 13.6m long, constructed using seamless stainless steel tubing with an absolute roughness of 0.2mm. It includes three 90° gentle bends and one regulating butterfly valve. The operating conditions are standard atmospheric sea level (pressure 101.325kPa, air temperature 15℃), and the calculated density is 1.225kg / m³. 3 The dynamic viscosity coefficient is 1.82×10⁻⁵ Pa·s. Using an ideal gas model, the parameters are substituted into equations (14) to (17) to obtain the following results:

[0141]

[0142]

[0143] If Re is greater than 4000, it indicates turbulence. The turbulence algorithm (16) is used. Since this function is implicit, after iterative solution, we obtain:

[0144]

[0145] The pressure loss coefficient introduced by a 90° gentle turn is found to be 0.5, therefore:

[0146]

[0147] The pressure loss coefficient introduced by the butterfly valve is found to be 0.05.

[0148]

[0149] Substituting the pipe length and diameter, we get:

[0150]

[0151] The total pressure loss along the friction path is 9.36 kPa, which meets the design requirements.

[0152] A high-precision regulating valve is installed on the intake section. The high-precision regulating valve is an electric butterfly valve with a response time of less than 0.5 seconds and a control accuracy of ±1%FS.

[0153] Grate sealing section: The designed grate gap Δr = 1mm, and the inner diameter of the grate section is 154mm. The designed grate tooth height is 6mm, that is, the diameter at the tooth height of the grate section is Db = 166mm. The number of grate teeth is 10, the bevel angle is 30°, the length of the larger side is 5mm, and the total length of the grate section is designed to be 55mm.

[0154] The housing is constructed entirely of 304 stainless steel, with the design pressure determined based on the simulated altitude, simulating a minimum of 12 kPa (corresponding to an altitude of 15 km). The housing wall thickness is determined through finite element analysis to ensure structural strength under extreme conditions. The housing exterior is covered with a cryogenic protective layer. Three sets of static pressure measuring points are located on both the left and right housings. The auxiliary power unit testing and electrical cable routing holes are designed on the top of the right housing, and are sealed with high-temperature resistant sealant after cable connection. Silicone sealing rings are used for compression sealing between the left and right housings and between the left and right housings and the mounting platform base. The housing connections and fastenings utilize flange connections. The entire housing is mounted below the engine's front intake manifold. During testing, the intake connection hole connects to the intake flow measurement section, sealed with a silicone gasket, and fixed with a flange. The exhaust pipe connection hole connects to the straight section of the exhaust pipe, sealed with a silicone gasket, and fixed with a flange.

[0155] The main structure of the auxiliary power unit installation platform is made of 304 stainless steel, and the load-bearing pin of the adjustment mechanism is made of high-strength alloy steel. The Y-axis adjustment mechanism is a threaded type adjustment mechanism with high-precision fine threads. The X and Z-axis adjustment mechanisms are strip-hole adjustment structures. Soft rubber washers are used to isolate vibration transmission between the test bench and the adapter, and the vibration value measured by strain gauges is no greater than 45 mm / s.

[0156] The exhaust pipe is made of Inconel 625 high-temperature alloy and is designed to operate at temperatures up to 1000℃. The pipe diameter is determined based on the exhaust flow rate of the auxiliary power unit. A gradually expanding guide section can be added to reduce the flow velocity of the discharged high-temperature gas and control the flow velocity within the range of 50-80 m / s.

[0157] The distance between the exhaust pipe outlet and the high-altitude test exhaust diffuser is no more than 10 times the outlet diameter. High-temperature gases from the auxiliary power unit are introduced into the high-altitude test exhaust system using engine exhaust ejector and the high-altitude test exhaust pump unit. The exhaust temperature sensing element uses a type K thermocouple, and the exhaust pressure sensor uses a high-temperature pressure sensor.

[0158] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of the present invention should still fall within the scope of the present invention. Furthermore, the technical features, technical features and technical solutions, and technical solutions in the present invention can be freely combined and used.

Claims

1. A design method for a joint debugging device for auxiliary power and engine in a test chamber, comprising: The support platform (3) is equipped with a box (2), and an auxiliary power unit is installed in the inner cavity of the box (2); an air intake pipe (1) is connected to the air intake pipe mixer of the high-altitude platform at the inlet end and to the air intake port of the auxiliary power unit in the inner cavity of the box (2); an exhaust pipe (4) is connected to the air intake port of the auxiliary power unit in the inner cavity of the box (2) at the inlet end and to the exhaust diffuser of the high-altitude cabin at the outlet end. The air intake pipe (1) along the gas flow direction includes, in sequence: an air intake section (16), which is connected to the air intake pipe mixer of the high-altitude test platform; a guide straight section (15), which is provided with a gradually narrowing guide section and a straight section for stabilizing the flow, the large diameter end of the guide section is connected to the outlet of the air intake section (16), and the small diameter end of the guide section is connected to the inlet of the straight section; and a toothed sealing section (14), which is connected to the outlet of the straight section, and the inner wall of the toothed sealing section (14) is provided with a toothed structure for sealing. The feature is that the design method for the joint debugging device of auxiliary power and engine in the test chamber includes: Step 1: Determine the inner diameter of the inlet flow measurement section based on the air intake method of the auxiliary power unit; Step 2: Design the shape of the contraction segment using a segmented double-twist line design method; Step 3: Design the inner diameter of the tooth section based on the tooth gap; Step 4: Select the inner diameter of the forecourt intake section and determine the design parameters of the forecourt intake section based on the mass flow rate; Step one specifically involves: When the auxiliary power unit uses axial air intake, the inner diameter of the inlet flow measurement section is the same as the inner diameter of the auxiliary power unit. When the auxiliary power unit uses a non-axial intake method, according to the formula... Calculate the minimum inner diameter D of the inlet flow measurement section. in,min Where W is the maximum airflow rate of the auxiliary power unit under standard conditions; ρ is the air density under standard conditions; Ma is the Mach number in the design flow tube; γ is the specific heat ratio of air; R is the gas constant; T is the gas temperature; and π is pi.

2. The design method of the auxiliary power and engine joint debugging device in the test chamber according to claim 1, characterized in that, Step one also includes: Calculate the Reynolds number of the inlet flow measurement section. ; The pressure loss coefficient is calculated based on the Reynolds number of the inlet flow measurement section. ; According to the formula Calculate the friction loss along the inlet flow measurement section. When the pressure loss along the inlet flow measurement section If the inlet flow measurement section is less than or equal to the set value, then the design meets the requirements. Where μ is the gas dynamic viscosity coefficient, D in The inner diameter of the inlet flow measurement section is D. in =D in,min ε is the absolute roughness of the inner wall of the pipe, and L is the length of the inlet flow measurement section.

3. The design method of the auxiliary power and engine joint debugging device in the test chamber according to claim 2, characterized in that, The specific design method for the segmented double-twisted wire is as follows: ； ； ； ; ； Where x is the axial dimension of the contraction section surface; y is the radial dimension of the contracted section surface; r1 is the radius of the larger end of the contraction segment; r2 is the radius of the smaller end of the contraction segment; l c This is the total length of the contraction segment; x i The axial dimension of the inflection point of the segmented double-twist line; The contraction rate of the first segment of the contraction segment; The contraction rate of the latter part of the contraction segment; k is the inflection point coefficient.

4. The design method of the auxiliary power and engine joint debugging device in the test chamber according to claim 3, characterized in that, Step three specifically involves: using the formula Calculate the inner diameter of the toothed section, where, For the gap between the teeth, The inner diameter of the comb tooth section. To measure the outer diameter of the section, and , where n' is the wall thickness of the inlet flow measurement section.

5. The design method of the auxiliary power and engine joint debugging device in the test chamber according to claim 4, characterized in that, Step four specifically involves: According to the formula Calculate the air velocity in the forecourt intake section; According to the formula Calculate the Reynolds number of the airflow in the forecourt section; According to the formula Calculate the pressure loss coefficient introduced by roughness in the air intake section of the forecourt; According to the formula Calculate the pressure loss along the air intake section of the anterior chamber; in, v f The air velocity in the anterior chamber intake section; R ef The Reynolds number is the number of airflow in the anterior chamber intake section. λ i This is the pressure loss coefficient introduced by roughness; ε f The absolute roughness of the ductwork in the anterior chamber intake section; λ j The pressure loss coefficient introduced by the pipe elbow, where n is the number of elbows; λ k The pressure loss coefficient of the pipeline valves is determined according to the valve type, and m is the number of pipeline valves; This refers to the pressure loss along the intake section of the anterior chamber; D f The diameter of the large end of the contraction section; L f This refers to the length of the duct in the forecourt air intake section.

6. The design method of the auxiliary power and engine joint debugging device in the test chamber according to claim 5, characterized in that, It also includes step five, adapting the design of the housing, auxiliary power unit mounting platform, and exhaust pipe.

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