Method and system for measuring throat area of low-pressure turbine guider of aero-engine

Abstract

The invention discloses a method and a system for measuring the throat area of a low-pressure turbine guider of an aero-engine. The method comprises the following steps of: fixing the low-pressure turbine guider to be measured at a constant state, and sealing an inner ring, an outer ring and an end face of the low-pressure turbine guider; introducing a constant airflow into the air inlet of the low-pressure turbine guider at a constant rotating speed by adopting airflow equipment so as to generate a constant pressure difference between the air inlet and the air outlet of the low-pressure turbine guider; according to the rotating speed of the airflow equipment, the flow is determined by searching the rotating speed-flow characteristic curve; and calculating the throat area according to the pressure difference and the flow. The measurement of the throat area of the low-pressure turbine guider is realized based on an airflow method, the accuracy is high, and the measurement is not influenced by the change of the throat area caused by the change of the structure of the low-pressure turbine guider.

Description

Technical Field

[0001] The invention belongs to the technical field of throat area measurement of a low-pressure turbine guide vane, and in particular relates to a method and system for measuring the throat area of ​​a low-pressure turbine guide vane of an aircraft engine. Background Art

[0002] The throat area of ​​the low-pressure turbine guide vane has a direct impact on the temperature before and after the turbine stage, the airflow field, the engine flow, thrust, speed and fuel consumption rate, etc. It also has a great impact on the stable operation of the engine, the matching of the compressor and the turbine, etc. Therefore, there are strict requirements for this parameter in the design and production of the engine.

[0003] At present, the three-coordinate measurement method is uniformly used in the manufacturing and maintenance of domestic aircraft engines. Through the geometric approximation method, points are taken on fixed cross sections to obtain the approximate value of the throat area of ​​the low-pressure turbine guide vane. The three-coordinate measurement accuracy of the spatial point coordinates is very high, but it cannot adapt to the changes in the throat area caused by the structural changes of the low-pressure turbine guide vane during the use of the engine. Summary of the invention

[0004] In order to solve the problems that the existing method for measuring the throat area of ​​a low-pressure turbine guide vane is low in accuracy and cannot be adapted to the change in throat area caused by the change in the structure of the low-pressure turbine guide vane, the present invention proposes a method and system for measuring the throat area of ​​a low-pressure turbine guide vane of an aircraft engine.

[0005] The objective of the present invention is achieved through the following technical solutions: The first aspect of the present invention discloses a method for measuring the throat area of ​​a low-pressure turbine guide vane of an aircraft engine, comprising the following steps: The guide vane of the low-pressure turbine to be tested is fixed at a fixed position and its inner ring, outer ring and end face are sealed; Using an airflow device to introduce a constant airflow into the air inlet of the low-pressure turbine guide device at a constant rotation speed to generate a constant pressure difference between the air inlet and the air outlet of the low-pressure turbine guide device; Determine the flow rate by looking up the speed-flow characteristic curve according to the speed of the airflow device; The throat area is calculated based on the pressure difference and flow rate.

[0006] A second aspect of the present invention discloses a low-pressure turbine guide vane throat area measurement system, which implements throat area measurement based on the method described in the first aspect, and comprises: A clamping and fixing structure for fixing a low-pressure turbine guide vane to be tested; Sealing structure for sealing the inner ring, outer ring and end face of the low-pressure turbine guide vane; An air flow device for introducing a constant air flow into the air inlet of the low-pressure turbine guide vane; A computing device for determining the flow rate by searching a speed-flow rate characteristic curve according to the speed of the airflow device and calculating the throat area according to the pressure difference and the flow rate.

[0007] The beneficial effects of the present invention are: The present invention realizes the measurement of the throat area of ​​the low-pressure turbine guide vane based on the airflow method, has high accuracy and is not affected by the change of the throat area caused by the change of the low-pressure turbine guide vane structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0009] Figure 1 It is a schematic structural diagram of the throat area measurement system of the low-pressure turbine guide vane of the present invention. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0011] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0012] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0013] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0014] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use, or the positions or positional relationships commonly understood by those skilled in the art, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0015] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it 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, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0016] The first aspect of the present invention discloses a method for measuring the throat area of ​​a low-pressure turbine guide vane of an aircraft engine, comprising steps S11 to S14. It should be noted that the step identifiers in this solution are only for the convenience of explaining the method, and do not constitute a sequence limitation. The sequence of each step is based on its language description and the sequence of each signal.

[0017] Step S11, fix the low-pressure turbine guide vane 2 and seal its inner ring, outer ring and end face.

[0018] Specifically, for the outer ring of the low-pressure turbine guide vane: the upper end face of the low-pressure turbine guide vane outer ring is sealed with the upper end face of the guide vane blade intake side outer ring through a silicone plate; the lower end face of the low-pressure turbine guide vane outer ring is sealed with the lower end face of the low-pressure turbine guide vane outer casing exhaust side through a rubber sealing ring. The two annular tooling used for sealing the outer ring of the low-pressure turbine guide vane is sealed on the end face with a rubber sealing ring, and is tightened and locked with 12 M6 evenly distributed hexagonal screws. All sealing end faces have sufficient sealing compression to ensure the sealing effect. In addition, the low-pressure turbine guide vane outer casing and the low-pressure turbine guide vane exhaust side have corresponding sealing designs.

[0019] For the inner ring of the low-pressure turbine guide vane: the upper end face of the inner ring of the low-pressure turbine guide vane is sealed with the upper end face of the inner ring on the intake side of the guide vane through a rubber plate; the lower end face of the inner ring of the low-pressure turbine guide vane is sealed with the lower end face of the exhaust side of the low-pressure turbine guide vane through a rubber sealing ring. The two annular tooling used for sealing the inner ring of the low-pressure turbine guide vane is radially sealed through two sealing rings on the central core rod.

[0020] For the first-stage guide vane of the low-pressure turbine guide vane: the end face is compressed and sealed by the silicone plate. By rotating the four set screws, the steel plate is pressed against the silicone plate on the lower end face, so that the circumferential edge of the first-stage guide vane fits with the lower end face of the silicone plate to achieve sealing.

[0021] Step S12: using an airflow device to introduce a constant airflow into the air inlet of the low-pressure turbine guide valve at a constant rotation speed to generate a constant pressure difference between the air inlet and the air outlet of the low-pressure turbine guide valve.

[0022] Specifically, the air flow device of this step can be a blower 4. In order to improve the calculation accuracy of the throat area, the blower 4 has wind speed control accuracy, and there is no air flow obstruction within 1m of the outlet so that the discharged air flow should flow freely without obstruction, and prevent the discharged air from returning to the air flow, which will cause unstable measurement.

[0023] After the low-pressure turbine guide vane is fixed and sealed, the airflow device is turned on to rotate the blower at a constant speed to form a constant pressure difference, so that the airflow passes through the low-pressure turbine guide vane at a stable flow rate to form an airflow channel.

[0024] In order to improve the accuracy of controlling the pressure difference between the air inlet and the air outlet of the low-pressure turbine guide vane, a pressure difference sensor may be provided at the air inlet and the air outlet of the low-pressure turbine guide vane, respectively, and the pressure difference sensor is used to detect the air pressure at the air inlet and the air outlet of the low-pressure turbine guide vane; then the difference between the air pressure at the air inlet and the air outlet is calculated; and the difference is compared with the pressure difference to determine the accuracy of the pressure difference.

[0025] Step S13: Determine the flow rate by searching the speed-flow rate characteristic curve according to the speed of the airflow device.

[0026] Step S14: Calculate the throat area according to the pressure difference and flow rate.

[0027] Specifically, according to the Bernoulli equation, when the inlet and outlet pressure difference of the low-pressure turbine guide vane is fixed and the outlet flow of the guide vane is fixed, its flow, inlet and outlet pressure difference and throat area satisfy the following formula: , Wherein, m is the flow rate, C0 is the correction coefficient, A is the throat area, and Δp is the pressure difference between the inlet and outlet of the low-pressure turbine guide vane.

[0028] To this end, this step first calculates the inlet and outlet pressure difference of the low-pressure turbine guide valve based on the air pressure at the inlet and outlet of the low-pressure turbine guide valve, then determines the flow rate based on the speed-flow characteristic curve and speed of the blower, and finally calculates the throat area using the Bernoulli equation based on the inlet and outlet pressure difference and flow rate of the low-pressure turbine guide valve.

[0029] The above method measures the throat area of ​​the low-pressure turbine guide vane by the airflow method, which is highly accurate and can achieve precise measurement; and there is no need to select relevant coordinates according to the preset throat position, and the measurement is performed according to fluid dynamics, avoiding errors and human interference. The entire measurement process is simple and fast, saving time and labor costs.

[0030] Compared with the existing methods, this method can reduce the measurement time of a single unit by 20%, saving time costs and having good application prospects.

[0031] Based on the above method, the second aspect of the present invention discloses a low-pressure turbine guide vane throat area measurement system, such as Figure 1 As shown, the system includes a clamping and fixing structure for fixing the low-pressure turbine guide vane 2 to be tested, a sealing structure 1 for sealing the inner ring, outer ring and end face of the low-pressure turbine guide vane, an airflow device for introducing a constant airflow into the air inlet of the low-pressure turbine guide vane, and a calculation device for determining the flow rate by looking up the speed-flow characteristic curve according to the speed of the airflow device and obtaining the throat area according to the pressure difference and flow rate calculation.

[0032] In order to verify the reliability of the constant pressure difference between the air inlet and the air outlet of the low-pressure turbine guide vane, a measuring device for measuring the air pressure data of the air inlet and the air outlet of the low-pressure turbine guide vane is also included. The measuring device is a differential pressure measuring meter.

[0033] Specifically, the air flow device is a blower and a motor 5 for providing power to the blower 4. The measuring device is a differential pressure meter 3.

[0034] It should be noted that Figure 1 The arrows in the figure represent the airflow direction. The operating principle of this system is detailed in the first aspect and will not be described here.

[0035] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A method for measuring the throat area of ​​a low-pressure turbine guide vane of an aircraft engine, characterized in that: The following steps are involved: The guide vane of the low-pressure turbine to be tested is fixed at a fixed position and its inner ring, outer ring and end face are sealed; Using an airflow device to introduce a constant airflow into the air inlet of the low-pressure turbine guide device at a constant rotation speed to generate a constant pressure difference between the air inlet and the air outlet of the low-pressure turbine guide device; Determine the flow rate by looking up the speed-flow characteristic curve according to the speed of the airflow device; The throat area is calculated based on the pressure difference and flow rate.

2. The method for measuring throat area of ​​a low-pressure turbine guide vane of an aircraft engine according to claim 1, characterized in that: The method of fixing the low-pressure turbine guide vane and sealing the inner ring, outer ring and end face thereof comprises: The upper end face of the outer ring of the low-pressure turbine guide vane is sealed with the upper end face of the outer ring on the intake side of the guide vane through a silicone plate, and the lower end face of the outer ring of the low-pressure turbine guide vane is sealed with the lower end face of the exhaust side of the outer casing of the low-pressure turbine guide vane through a rubber sealing ring; The upper end face of the inner ring of the low-pressure turbine guide vane is sealed with the upper end face of the inner ring of the guide vane on the intake side through a rubber plate, and the lower end face of the inner ring of the low-pressure turbine guide vane is sealed with the lower end face of the exhaust side of the low-pressure turbine guide vane through a rubber sealing ring; A silicone plate is used to perform end face compression sealing on the first-stage guide vane of the low-pressure turbine guide vane.

3. The method for measuring throat area of ​​a low-pressure turbine guide vane of an aircraft engine according to claim 1, characterized in that: The airflow device is a blower, and there is no airflow obstruction within 1m of the blower outlet.

4. The method for measuring throat area of ​​a low-pressure turbine guide vane of an aircraft engine according to claim 1, characterized in that: The method of using an airflow device to introduce a constant airflow into the air inlet of the low-pressure turbine guide device at a constant speed to generate a constant pressure difference between the air inlet and the air outlet of the low-pressure turbine guide device also includes: A differential pressure sensor is used to detect the air pressure at the inlet and outlet of the low-pressure turbine guide vane; Calculating the difference between the air pressure at the air inlet and the air outlet; The difference is compared to the pressure differential to determine the accuracy of the pressure differential.

5. A system for measuring throat area of ​​low-pressure turbine guide vane of an aircraft engine, characterized in that: The system realizes laryngeal area measurement based on the method described in any one of claims 1 to 4, and the system comprises: A clamping and fixing structure for fixing a low-pressure turbine guide vane to be tested; Sealing structure for sealing the inner ring, outer ring and end face of the low-pressure turbine guide vane; An airflow device for introducing a constant airflow into the air inlet of the low-pressure turbine guide vane to generate a constant pressure difference between the air inlet and the air outlet of the low-pressure turbine guide vane; A computing device for determining the flow rate by searching a speed-flow rate characteristic curve according to the speed of the airflow device and calculating the throat area according to the pressure difference and the flow rate.

6. The system for measuring throat area of ​​a low-pressure turbine guide vane of an aircraft engine according to claim 5, characterized in that: Also included is a measuring device for measuring the air pressure data at the air inlet and air outlet of the low-pressure turbine guide vane.

7. The system for measuring throat area of ​​a low-pressure turbine guide vane of an aircraft engine according to claim 6, characterized in that: The measuring device is a differential pressure meter.

8. The system for measuring throat area of ​​a low-pressure turbine guide vane of an aircraft engine according to claim 5, characterized in that: The air flow device is a blower and a motor that provides power to the blower.

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