A bidirectional transient flow measurement method for measuring surge characteristics in aircraft engine tests

Abstract

The present application belongs to the technical field of bidirectional transient flow measurement for measuring surge characteristics of aircraft engine tests, and specifically relates to a bidirectional transient flow measurement method for measuring surge characteristics of aircraft engine tests. The method is designed to arrange multiple transient conversion flow measurement instruments along the circumference on the flow channel measurement section, and the support rod of each transient conversion flow measurement instrument extends into the flow channel. Multiple measurement stacks are arranged radially, and a forward total pressure measurement point is set at the leading edge of the section where each measurement stack is located, a reverse total pressure measurement point is set at the trailing edge, and static pressure measurement points are set on both sides. Then, through the measurement values of each measurement point, it is determined whether surge occurs and the backflow characteristics are determined, and the transient flow in the flow channel can be obtained, including the transient flow in both forward and reverse directions, and the backflow flow is obtained, which meets the measurement requirements of the surge characteristics and the response requirements of the transient flow changes, and accurately captures the static pressure unevenness characteristics.

Description

Technical Field

[0001] The present application belongs to the technical field of bidirectional transient flow measurement for measuring surge characteristics in aircraft engine tests, and specifically relates to a bidirectional transient flow measurement method for measuring surge characteristics in aircraft engine tests. Background Art

[0002] Currently, when testing aircraft engines, orifice plates, venturi tube differential pressure flow measurement devices, and twisted-wire venturi tube flow measurement devices are mainly used to measure the flow in the flow channel. However, these flow measurement devices are all based on steady-state flow measurement design. They cannot meet the response requirements for dynamic transient flow changes, cannot accurately capture the static pressure unevenness characteristics, cannot determine the backflow characteristics when the aircraft engine surges, and cannot measure the backflow flow, which cannot meet the measurement requirements of surge characteristics.

[0003] This application is proposed in view of the above-mentioned technical defects.

[0004] It should be noted that the disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of this application, and it does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0005] The purpose of this application is to provide a bidirectional transient flow measurement method for measuring surge characteristics of aircraft engines to overcome or alleviate at least one of the existing technical defects.

[0006] The technical solution of this application is:

[0007] A bidirectional transient flow measurement method for measuring surge characteristics of an aircraft engine test, comprising:

[0008] On the flow channel measurement section, multiple transient conversion flow measurement instruments are arranged along the circumference, including:

[0009] The support rod of each transient conversion flow measuring instrument extends into the flow channel, and multiple measuring stacks are arranged along the radial direction;

[0010] A positive total pressure measuring point facing the positive direction of the airflow in the flow channel is set at the leading edge of the section where each measurement stack is located, a negative total pressure measuring point opposite to the positive total pressure measuring point is set at the trailing edge, and static pressure measuring points perpendicular to the airflow direction in the flow channel are set on both sides;

[0011] Determine the direction of airflow in the flow channel. If P A >P B , the airflow in the channel flows forward; if P A =PB , the airflow in the flow channel stops flowing; if P A <P B , then the airflow in the channel flows in the opposite direction, where P A P is the pressure value measured at the positive total pressure measuring point; B The pressure value measured at the reverse total pressure measuring point;

[0012] Calculate the transient flow rate in the flow channel:

[0013]

[0014] in,

[0015] W is the transient flow rate in the flow channel;

[0016] K W is the flow coefficient in the flow channel;

[0017] m is the gas dynamics coefficient in the flow channel;

[0018] A e is the effective flow area of the flow channel;

[0019] γ is the specific heat ratio of the airflow in the flow channel;

[0020] R is the gas constant;

[0021] P t Measure the average value of the total pressure in the incoming flow direction in the flow channel for each forward total pressure measuring point and reverse total pressure measuring point;

[0022] P s Measure the average static pressure of the airflow in the flow channel for each static pressure measuring point.

[0023] According to at least one embodiment of the present application, in the above-mentioned method for measuring the bidirectional transient flow rate of the aircraft engine test surge characteristics, K W The value of is obtained by measuring the boundary layer inside the flow channel.

[0024] According to at least one embodiment of the present application, in the above-mentioned method for measuring bidirectional transient flow rate in the surge characteristic measurement of an aircraft engine test,

[0025] According to at least one embodiment of the present application, in the above-mentioned method for measuring the bidirectional transient flow rate of the aircraft engine test surge characteristics, A e The value is equal to the measured cross-sectional area of the flow channel minus the windward area of each support rod.

[0026] This application has at least the following beneficial technical effects:

[0027] Provided is a bidirectional transient flow measurement method for measuring surge characteristics in aircraft engine tests. The method comprises the following steps: a plurality of transient conversion flow measurement instruments are arranged circumferentially on a flow channel measurement section, a support rod of each transient conversion flow measurement instrument extends into the flow channel, and a plurality of measurement stacks are arranged radially. A forward total pressure measurement point is set at the leading edge of the section where each measurement stack is located, a reverse total pressure measurement point is set at the trailing edge, and static pressure measurement points are set on both sides. The measurement values of the various measurement points are then used to determine whether surge has occurred and the backflow characteristics. The method can also determine the transient flow in the flow channel, including the forward and reverse transient flow rates, and the backflow flow rate. This method satisfies the measurement requirements for surge characteristics and the response requirements for transient flow changes, and accurately captures the static pressure unevenness characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of an embodiment of the present application providing a plurality of transient conversion flow measurement instruments arranged circumferentially on a flow channel measurement section;

[0029] Figure 2 This is a schematic diagram of the arrangement of measuring points on the cross section of each measuring stack on the support rod of the transient conversion flow measurement instrument provided by an embodiment of the present application;

[0030] in:

[0031] 1-flow channel; 2-transient conversion flow measurement instrument; 3-support rod; 4-measuring stack;

[0032] A-forward total pressure measuring point;

[0033] B-reverse total pressure measuring point;

[0034] C-Static pressure measuring point.

[0035] In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be understood as limitations on this patent. DETAILED DESCRIPTION

[0036] To make the technical solution and its advantages of the present application clearer, the technical solution of the present application will be described in further detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of the present application and are only used to explain the present application, not to limit the present application. It should be noted that, for ease of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0037] In addition, unless otherwise defined, the technical or scientific terms used in the description of this application should have the ordinary meanings understood by those of ordinary skill in the art to which this application belongs. The words "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer" used in the description of this application are only used to indicate relative directions or positional relationships, and do not imply that the device or component must have a specific orientation, be constructed, or operate in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. Therefore, they should not be understood as limitations on this application. The words "first," "second," "third," and similar terms used in the description of this application are used only for descriptive purposes to distinguish different components and should not be understood to indicate or imply relative importance. The words "one," "an," or "the" used in the description of this application should not be understood as absolute limitations on quantity, but should be understood as meaning the presence of at least one. The words "include" or "comprises" used in the description of this application mean that the element or object listed before the word includes the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0038] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "install", "connect", "connect" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between two components. Technical personnel in the field can understand their specific meanings in this application according to the specific circumstances.

[0039] The following is combined with Figures 1 to 2 This application is described in further detail.

[0040] A bidirectional transient flow measurement method for measuring surge characteristics of an aircraft engine test, comprising:

[0041] On the measuring section of the flow channel 1, multiple transient conversion flow measuring instruments 2 are arranged along the circumference, such as Figure 1 As shown, where:

[0042] The support rod 3 of each transient conversion flow measurement instrument 2 extends into the flow channel 1, and multiple measurement stacks 4 are arranged radially;

[0043] A forward total pressure measuring point A is set at the leading edge of the cross section of each measuring stack 4, facing the forward direction of the airflow in the flow channel 1, so as to measure the total pressure of the forward flow of the airflow in the flow channel 1. A reverse total pressure measuring point B is set at the trailing edge, facing the forward total pressure measuring point A, so as to measure the total pressure of the reverse flow of the airflow in the flow channel 1. Static pressure measuring points C are set on both sides, perpendicular to the flow direction of the airflow in the flow channel 1, so as to measure the static pressure of the airflow in the flow channel 1. Figure 2 As shown;

[0044] Determine the direction of the airflow in flow channel 1, and then determine whether surge occurs. If P A >P B , then the airflow in channel 1 flows forward; if P A =P B , then the airflow in channel 1 stops flowing; if P A <P B , then the airflow in channel 1 flows in the reverse direction, where P A is the pressure value measured at the positive total pressure measuring point A; P B The pressure value measured at the reverse total pressure measuring point B;

[0045] Calculate the transient flow rate in flow channel 1:

[0046]

[0047]

[0048] in,

[0049] W is the transient flow rate in flow channel 1;

[0050] K W is the flow coefficient in flow channel 1, which is obtained by measuring the boundary layer in flow channel 1;

[0051] m is the gas dynamics coefficient in flow channel 1;

[0052] A e is the effective flow area of the flow channel 1, which is equal to the measured cross-sectional area of the flow channel 1 minus the windward area of each support rod 3;

[0053] γ is the specific heat ratio of the airflow in flow channel 1;

[0054] R is the gas constant;

[0055] P t Measure the average value of the total pressure in the incoming flow direction in flow channel 1 for each forward total pressure measuring point A and reverse total pressure measuring point B;

[0056] P s The average static pressure of the airflow in the flow channel 1 is measured for each static pressure measuring point C.

[0057] As for the bidirectional transient flow measurement method for measuring surge characteristics of aircraft engine tests disclosed in the above embodiment, it can be understood by those skilled in the art that it is designed on the measurement section of the flow channel 1, with multiple transient conversion flow measurement instruments 2 arranged circumferentially, the support rod 3 of each transient conversion flow measurement instrument 2 extending into the flow channel 1, and multiple measurement stacks 4 arranged radially, and each measurement stack 4 is designed to be provided with a forward total pressure measurement point A at the leading edge of the section where the measurement stack 4 is located, a reverse total pressure measurement point B at the trailing edge, and static pressure measurement points C on both sides, and then, through the measurement values of each measurement point, it is determined whether surge occurs, the backflow characteristics are determined, and the transient flow in the flow channel 1 can be obtained, including the forward and reverse bidirectional transient flow, and the backflow flow is obtained, which meets the measurement requirements of the surge characteristics and the response requirements of the transient flow changes, and accurately captures the static pressure unevenness characteristics.

[0058] Each transient flow measuring instrument 2 has a measuring stack 3 with no less than 3 points on its support rod 3 in radial direction, and is arranged in the form of an equal annular surface.

[0059] The apertures of each forward total pressure measuring point A, reverse total pressure measuring point B, and static pressure measuring point C are 0.5 to 1 mm.

[0060] The inlet of each positive total pressure measuring point A and the reverse total pressure measuring point B is chamfered, and the chamfer size can be 0.2mm.

[0061] The center line of the C hole at each static pressure measuring point is perpendicular to the surface of the support rod 3 where it is located, the sharp edge of the opening is free of burrs, and chamfers are not allowed.

[0062] The inner diameter of the pressure lead-out pipeline of the forward total pressure measuring point A, the reverse total pressure measuring point B, and the static pressure measuring point C in each transient flow measuring instrument 2 is consistent with the aperture of the measuring point.

[0063] The pressure outlet pipelines of the forward total pressure measuring point A, the reverse total pressure measuring point B, and the static pressure measuring point C of each transient flow measuring instrument 2 are allowed to turn slowly but not to turn sharply. The turning form and number of all pressure outlet pipelines are consistent, and the inner diameter of each pressure outlet pipeline is gradually reduced.

[0064] The total length of the pressure outlet piping for each transient flow meter 2, at forward total pressure measuring point A, reverse total pressure measuring point B, and static pressure measuring point C, is the distance from forward total pressure measuring point A, reverse total pressure measuring point B, and static pressure measuring point C to the pressure measurement module. The pressure outlet piping for forward total pressure measuring point A, reverse total pressure measuring point B, and static pressure measuring point C is an integrated design with a consistent total length ranging from 0.5 to 2 meters.

[0065] The pressure measurement modules connected to each transient flow measurement instrument 2 have high-speed acquisition capabilities, and the response frequency should not be lower than 100 Hz.

[0066] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to in detail.

[0067] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or replacements to the relevant technical features, and the technical solutions after these changes or replacements will fall within the scope of protection of the present application.

Claims

1. A bidirectional transient flow measurement method for measuring surge characteristics of an aircraft engine test, characterized in that: include: On the measuring section of the flow channel (1), a plurality of transient conversion flow measuring instruments (2) are arranged along the circumferential direction, wherein: The support rod (3) of each transient conversion flow measurement instrument (2) extends into the flow channel (1), and a plurality of measurement stacks (4) are arranged radially; A positive total pressure measuring point A facing the positive direction of the airflow in the flow channel (1) is set at the leading edge of the cross section of each measuring stack (4), a negative total pressure measuring point B facing the positive total pressure measuring point A is set at the trailing edge, and static pressure measuring points C perpendicular to the airflow direction in the flow channel (1) are set on both sides; Determine the direction of airflow in channel (1). If P A >P B , then the airflow in channel (1) flows in the forward direction; if P A =P B , then the airflow in the flow channel (1) stops flowing; if P A <P B , then the airflow in channel (1) flows in the reverse direction, where P A is the pressure value measured at the positive total pressure measuring point A; P B The pressure value measured at the reverse total pressure measuring point B; Calculate the transient flow rate in flow channel (1): in, W is the transient flow rate in the flow channel (1); K W is the flow coefficient in the flow channel (1), and its value is obtained by measuring the boundary layer in the flow channel (1); m is the gas dynamics coefficient in the flow channel (1); A e is the effective flow area of the flow channel (1); γ is the specific heat capacity ratio of the air flow in the flow channel (1); R is the gas constant; P t The average value of the total pressure in the inflow direction in the flow channel (1) is measured at each forward total pressure measuring point A and reverse total pressure measuring point B; P s The average value of the static pressure of the air flow in the flow channel (1) is measured at each static pressure measuring point C.

2. The method for measuring bidirectional transient flow rate for measuring surge characteristics of an aircraft engine test according to claim 1, characterized in that: A e The value is equal to the measured cross-sectional area of the flow channel (1) minus the windward area of each support rod (3).

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