Self-adaptive air entraining adjusting structure for multi-working-condition radial clearance of air compressor and design method

Abstract

The invention relates to the field of design of gas compressors and gas guide flow paths of the gas compressors, and discloses a self-adaptive gas guide adjusting structure for multi-working-condition radial clearances of a gas compressor and a design method of the self-adaptive gas guide adjusting structure for the multi-working-condition radial clearances of the gas compressor. The self-adaptive adjustment of the bleed air flow in the first bleed air cavity at different rotating speeds is realized so as to heat the compressor disc cavity, and the operation of a pilot is not needed; the air entraining structure is simple, and the influence on the dynamic characteristics of the compressor rotor is small; besides, an analysis model between the cavity pressure of the control cavity and the rotating speed is constructed to determine the cavity pressure of the valve control cavity corresponding to different rotating speeds, and under the condition of considering valve structure parameters, the valve opening time is controlled, and it is ensured that the valve is completely opened at the preset rotating speed; therefore, the compressor disc cavity is heated by the first air entraining channel at the maximum air entraining amount at the preset rotating speed.

Description

Technical Field

[0001] The present invention relates to the field of compressors and the design of their air intake flow paths, and discloses an adaptive air intake regulation structure and design method for the radial clearance of a compressor under multiple working conditions. Background Art

[0002] As one of the core components of an aeroengine, the high-pressure compressor is a mechanical device whose main function is to transmit mechanical energy to the gas and complete the compression process of the gas working medium in the engine thermodynamic cycle to increase the gas pressure. Its performance has a crucial impact on the entire engine. The high-pressure compressor provides most of the cycle pressure ratio, and its load, efficiency level, and stable operating margin directly affect the overall fuel consumption rate, operating range, and reliability of the engine.

[0003] The radial clearance between the rotor and stator of the high-pressure compressor is an important factor affecting the aerodynamic performance, stability, and working reliability of the compressor. However, in engineering design, to ensure the safe and reliable operation of the aero-compressor under various working conditions, the radial clearance between the traditional compressor rotor and the corresponding casing is designed based on its most demanding working state during design. As a result, the radial clearance of the high-pressure compressor is only small under some large working states, while the radial clearance is large under other working states, seriously affecting the aerodynamic performance and operating margin of the high-pressure compressor under low working states.

[0004] Research shows that the main reason for the radial difference in the compressor under different working states is mainly due to the large deformation difference caused by the different pressure and thermal loads borne by the compressor rotor and stator. The existing compressor and its air intake flow path design cannot achieve an active control method for the radial clearance of the high-pressure compressor. Summary of the Invention

[0005] The purpose of the present invention is to provide an adaptive air intake regulation structure and design method for the radial clearance of a compressor under multiple working conditions, which can adaptively adjust the air intake flow rate in the first air intake cavity at different speeds to heat the compressor disk cavity.

[0006] To achieve the above technical effects, the technical solution adopted by the present invention is: An adaptive air intake regulation structure for the radial clearance of a compressor under multiple working conditions, comprising: A first air intake cavity, which is communicated with the inner cavity of the compressor stator casing and is used to introduce the air flow of the intermediate stage of the compressor into the first air intake cavity; A first air intake channel, which is communicated with the first air intake cavity and is used to introduce the air flow in the first air intake cavity into the compressor disk cavity; A valve, which is arranged on the first air intake channel. The valve includes a control cavity, an adjusting rod is arranged in the control cavity, and a return spring that abuts against the inner wall of the valve cavity is arranged on the adjusting rod; A second air extraction cavity, which is communicated with the inner cavity of the compressor stator casing, is used to introduce the air flow of the subsequent stage of the compressor into the second air extraction cavity, and the subsequent stage is the compressor rotor-stator stage downstream of the intermediate stage of the compressor; A second air extraction passage, one end of which is communicated with the second air extraction cavity, and the other end of the second air extraction passage is communicated with the control cavity of the valve, is used to introduce the air flow in the second air extraction cavity into the control cavity, so as to adjust the relative position of the adjusting rod according to the relative magnitude of the pressure in the second air extraction cavity and the elastic force of the return spring, and control the flow area of the first air extraction passage at the valve.

[0007] Further, the initial position of the adjusting rod is that the first air extraction passage is in a fully open state in the cold state. During the process that the compressor speed increases to the preset speed, the flow area of the valve gradually decreases.

[0008] Further, the initial position of the adjusting rod is that the first air extraction passage is in a fully closed state in the cold state. During the process that the compressor speed increases to the preset speed, the flow area of the valve gradually increases.

[0009] To achieve the above technical effects, the present invention also provides a design method for the adaptive air extraction regulation structure of the radial clearance of the compressor under multiple working conditions, which is used to obtain the design range value of the stiffness coefficient required by the return spring of the adaptive air extraction regulation structure of the radial clearance of the compressor under multiple working conditions, including: Obtain the static pressure value of the second air extraction cavity at the air extraction position of the subsequent stage of the compressor at the test speed, and the chamber pressure of the control cavity during the air extraction process; according to the static pressure value at the test speed and the chamber pressure of the control cavity during the air extraction process at the test speed, analyze and obtain the pressure loss coefficient of the second air extraction passage; Obtain the static pressure value of the second air extraction cavity at the air extraction position of the subsequent stage of the compressor at different speeds, and construct a first function relationship model between the static pressure value and the speed data value; According to the first function relationship model and the analyzed pressure loss coefficient of the second air extraction passage, construct a second function relationship model between the chamber pressure of the control cavity and the speed data value; Use the second function relationship model to calculate the chamber pressure of the control cavity of the compressor at the preset speed; According to the effective acting area of the air flow in the control cavity on the adjusting rod, the chamber pressure of the control cavity corresponding to the preset speed, and the minimum displacement length of the adjusting rod relative to the initial position of the adjusting rod when the first air extraction passage is fully open or fully closed, analyze and obtain the upper limit value of the stiffness coefficient of the return spring.

[0010] Further, the pressure loss coefficient of the second air extraction passage is obtained according to Analyzed and obtained, where is the pressure loss coefficient of the second air extraction passage, is the chamber pressure of the control chamber at the test speed, and is the static pressure value at the air extraction position of the second air extraction chamber at the rear stage of the compressor at the test speed.

[0011] Furthermore, the second function relationship model between the chamber pressure of the control chamber and the speed is , where is the first function relationship model between the static pressure value and the speed data value.

[0012] Furthermore, the upper limit value of the stiffness coefficient of the return spring , where is the chamber pressure of the control chamber corresponding to the preset speed of the compressor, is the effective action area of the airflow in the control chamber on the adjusting rod, is the minimum displacement length of the adjusting rod relative to the initial position of the adjusting rod when the first air extraction channel is fully opened or fully closed.

[0013] Furthermore, the initial position of the adjusting rod is that the first air extraction channel is in a fully open state in the cold state. During the process of the compressor speed increasing to the preset speed, the flow area of the valve gradually decreases.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention adaptively adjusts the position of the air extraction valve according to the pressure change of the rear stage of the compressor at different compressor speeds, so as to adaptively adjust the air extraction air flow rate in the first air extraction chamber at different speeds to heat the compressor disk cavity without the operation of the pilot; and the air extraction structure is simple, with high reliability, small weight and cost; all components are stator parts, which have little influence on the dynamic characteristics of the compressor rotor and low safety risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the adaptive air extraction adjustment structure of the compressor multi-condition radial clearance in the embodiment; Among them, 1, the first air extraction chamber; 2, the stator casing; 3, the first air extraction channel; 4, the compressor disk cavity; 5, the control chamber; 6, the adjusting rod; 7, the return spring; 8, the second air extraction chamber; 9, the second air extraction channel. DETAILED DESCRIPTION OF THE EMBODIMENT

[0016] The present invention will be further described in detail below in conjunction with the embodiments and the drawings. However, this should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments, and all technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0017] Embodiment Referring to Figure 1 , the adaptive air extraction adjustment structure of the compressor multi-condition radial clearance includes: The first air extraction cavity 1, which is communicated with the inner cavity of the compressor stator casing 2, is used to introduce the air flow of the intermediate stage of the compressor into the first air extraction cavity 1; The first air extraction passage 3, which is communicated with the first air extraction cavity 1, is used to introduce the air flow in the first air extraction cavity 1 into the compressor disk cavity 4; A valve, which is arranged on the first air extraction passage 3. The valve includes a control cavity 5. An adjusting rod 6 is arranged in the control cavity 5, and a return spring 7 which abuts against the inner wall of the valve cavity is arranged on the adjusting rod 6; The second air extraction cavity 8, which is communicated with the inner cavity of the compressor stator casing 2, is used to introduce the air flow of the subsequent stage of the compressor into the second air extraction cavity 8. The subsequent stage is the compressor rotor-stator stage downstream of the intermediate stage of the compressor; The second air extraction passage 9, one end of which is communicated with the second air extraction cavity 8, and the other end of which is communicated with the control cavity 5 of the valve, is used to introduce the air flow in the second air extraction cavity 8 into the control cavity 5, so as to adjust the relative position of the adjusting rod 6 according to the relative magnitudes of the pressure in the second air extraction cavity 8 and the elastic force of the return spring 7, and control the flow area of the first air extraction passage 3 at the valve.

[0018] In this embodiment, during the operation of the compressor, the air extraction pressure of the subsequent stage and the air extraction pressure of the intermediate stage change with the rotational speed. The position of the air extraction valve is adaptively adjusted by using the pressure change of the subsequent stage of the compressor at different compressor rotational speeds, so as to adaptively adjust the air extraction air flow rate in the first air extraction cavity 1 at different rotational speeds to heat the compressor disk cavity 4, effectively accelerating the engine warm-up speed without the need for pilot operation; moreover, the air extraction structure is simple, with high reliability and low weight cost; all components are stator parts, having little influence on the dynamic characteristics of the compressor rotor and low safety risks.

[0019] In this embodiment, by setting the initial position of the adjusting rod 6 such that the first air extraction passage 3 is in a fully open state in the cold state, during the process of the compressor rotational speed increasing to the preset rotational speed, the flow area of the valve gradually decreases. It can effectively accelerate the temperature rising speed of the engine rotor components during the operation of the compressor at low rotational speeds and control the change range of the transitional clearance; while at high rotational speeds, the flow area of the valve decreases to reduce the air flow rate in the compressor disk cavity 4 and improve the engine efficiency.

[0020] In some embodiments, the initial position of the adjusting rod 6 is such that the first air extraction passage 3 is in a fully closed state in the cold state. During the process of the compressor rotational speed increasing to the preset rotational speed, the flow area of the valve gradually increases, and it can be realized that the flow area of the valve is small at low rotational speeds and the flow area of the valve increases at high rotational speeds during the operation of the compressor as needed.

[0021] Based on the same inventive concept, this embodiment also provides a design method for the self - adaptive bleed air regulation structure of the compressor multi - operating - condition radial clearance, which is used to obtain the design range value of the stiffness coefficient required for the return spring 7 of the self - adaptive bleed air regulation structure of the compressor multi - operating - condition radial clearance, including: Step 1: Obtain the static pressure value of the second bleed air cavity 8 at the bleed air position of the rear stage of the compressor under the test speed, and the cavity pressure of the control cavity 5 during the bleed air process; according to the static pressure value under the test speed and the cavity pressure of the control cavity 5 during the bleed air process under the test speed, analyze and obtain the pressure loss coefficient of the second bleed air passage 9; In this embodiment, the pressure loss coefficient of the second bleed air passage 9 is obtained according to by analysis, where is the pressure loss coefficient of the second bleed air passage 9, is the cavity pressure of the control cavity 5 under the test speed, is the static pressure value of the second bleed air cavity 8 at the bleed air position of the rear stage of the compressor under the test speed.

[0022] Step 2: Obtain the static pressure value of the second bleed air cavity 8 at the bleed air position of the rear stage of the compressor at different speeds, and construct the first function relationship model between the static pressure value and the speed data value.

[0023] Step 3: According to the first function relationship model and the analyzed pressure loss coefficient of the second bleed air passage 9, construct the second function relationship model between the cavity pressure of the control cavity 5 and the speed data value; In this embodiment, the second function relationship model between the cavity pressure of the control cavity 5 and the speed is where is the first function relationship model between the static pressure value and the speed data value.

[0024] Step 4: Use the second function relationship model to calculate the cavity pressure of the control cavity 5 of the compressor at the preset speed; Step 5: According to the effective acting area of the air flow in the control cavity 5 on the adjusting rod 6, the cavity pressure of the control cavity 5 corresponding to the preset speed, and the minimum displacement length of the adjusting rod 6 relative to the initial position of the adjusting rod 6 when the first bleed air passage 3 is fully opened or fully closed, analyze and obtain the upper limit value of the stiffness coefficient of the return spring 7; In this embodiment, the upper limit value of the stiffness coefficient of the return spring 7 where is the cavity pressure of the control cavity 5 corresponding to the preset speed of the compressor, is the effective acting area of the air flow in the control cavity 5 on the adjusting rod 6, is the minimum displacement length of the adjusting rod 6 relative to the initial position of the adjusting rod 6 when the first bleed air passage 3 is fully opened or fully closed.

[0025] In this embodiment, an analysis model between the chamber pressure of the control chamber 5 and the rotational speed is constructed to determine the chamber pressure of the valve control chamber 5 corresponding to different rotational speeds. Under the condition of considering the valve structure parameters, the control of the valve opening timing is realized and it is ensured that the valve is fully opened at the preset rotational speed, so as to realize heating the compressor disk cavity 4 with the maximum air extraction volume of the first air extraction channel 3 at the preset rotational speed.

[0026] It should be noted that the preset rotational speed can be a high rotational speed or a low rotational speed. For example, if it is necessary to effectively accelerate the temperature rise rate of the engine rotor components at a low rotational speed during the operation of the compressor and control the change range of the transitional clearance; while at a high rotational speed, the flow area of the valve decreases to reduce the air flow rate of the compressor disk cavity 4 and improve the engine efficiency; at this time, the initial position of the adjusting rod 6 can be set so that the first air extraction channel 3 is in a fully opened state in the cold state. Thus, during the process of the compressor rotational speed increasing to the preset rotational speed, the flow area of the valve gradually decreases.

[0027] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An adaptive bleed air regulation structure for the radial clearance of a compressor under multiple operating conditions, characterized in that Comprising: A first air extraction cavity, which is communicated with the inner cavity of the compressor stator casing and is used for introducing the air flow of the intermediate stage of the compressor into the first air extraction cavity; A first air extraction passage, which is communicated with the first air extraction cavity and is used for introducing the air flow in the first air extraction cavity into the compressor disk cavity; A valve, which is arranged on the first air extraction passage. The valve includes a control cavity, an adjusting rod is arranged in the control cavity, and a return spring which abuts against the inner wall of the valve cavity is arranged on the adjusting rod; A second air extraction cavity, which is communicated with the inner cavity of the compressor stator casing and is used for introducing the air flow of the subsequent stage of the compressor into the second air extraction cavity. The subsequent stage is the compressor rotor-stator stage downstream of the intermediate stage of the compressor; A second air extraction passage, one end of the second air extraction passage is communicated with the second air extraction cavity, and the other end of the second air extraction passage is communicated with the control cavity of the valve. It is used for introducing the air flow in the second air extraction cavity into the control cavity to adjust the relative position of the adjusting rod according to the relative magnitude of the pressure in the second air extraction cavity and the elastic force of the return spring, so as to control the flow area of the first air extraction passage at the valve; 2. The adaptive bleed air regulation structure for the radial clearance of a compressor under multiple operating conditions according to claim 1, characterized in that, The initial position of the adjusting rod is that the first air extraction passage is in a fully open state in the cold state. During the process that the compressor speed increases to the preset speed, the flow area of the valve gradually decreases.

3. The adaptive bleed air regulation structure for the radial clearance of a compressor under multiple operating conditions according to claim 1, wherein The initial position of the adjusting rod is that the first air extraction passage is in a fully closed state in the cold state. During the process that the compressor speed increases to the preset speed, the flow area of the valve gradually increases.

4. Design method of adaptive bleed air regulation structure for radial clearance of compressor under multiple operating conditions, which is used to obtain the design range value of the stiffness coefficient required for the return spring of the adaptive bleed air regulation structure for radial clearance of the compressor described in claim 1, characterized in that, Comprising: Obtaining the static pressure value of the second air extraction cavity at the air extraction position of the subsequent stage of the compressor at the test speed of the compressor, and the chamber pressure of the control cavity during the air extraction process; Analyzing and obtaining the pressure loss coefficient of the second air extraction passage according to the static pressure value at the test speed and the chamber pressure of the control cavity during the air extraction process at the test speed; Obtaining the static pressure value of the second air extraction cavity at the air extraction position of the subsequent stage of the compressor at different speeds of the compressor, and constructing a first function relationship model between the static pressure value and the rotational speed data value; According to the first function relationship model and the analyzed pressure loss coefficient of the second air extraction passage, constructing a second function relationship model between the chamber pressure of the control cavity and the rotational speed data value; Calculating the chamber pressure of the control cavity of the compressor at the preset speed by using the second function relationship model; Analyzing and obtaining the upper limit value of the stiffness coefficient of the return spring according to the effective acting area of the air flow in the control cavity on the adjusting rod, the chamber pressure of the control cavity corresponding to the preset speed, and the minimum displacement length of the adjusting rod relative to the initial position of the adjusting rod when the first air extraction passage is fully opened or fully closed.

5. The design method according to claim 4, characterized in that The pressure loss coefficient of the second bleed air passage is obtained according to analysis, where is the pressure loss coefficient of the second bleed air passage, is the chamber pressure of the control chamber at the test speed, is the static pressure value at the bleed air position of the second bleed air chamber at the rear stage of the compressor at the test speed.

6. The design method according to claim 4, characterized in that The second functional relationship model between the chamber pressure of the control chamber and the rotational speed is , where is the first functional relationship model between the static pressure value and the rotational speed data value.

7. The design method according to claim 4, wherein Upper limit value of the spring constant of the return spring , where is the control chamber pressure corresponding to the preset speed of the compressor, is the effective acting area of the airflow in the control chamber on the adjusting rod, is the minimum displacement length of the adjusting rod relative to the initial position of the adjusting rod when the first air extraction channel is fully opened or fully closed.

8. The design method according to claim 7, wherein The initial position of the adjusting rod is that the first air extraction passage is in a fully open state in the cold state. During the process that the compressor speed increases to the preset speed, the flow area of the valve gradually decreases.

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