A flow detection test section structure for the low-pressure turbine guide vane of an aeroengine

Abstract

A flow detection test section structure for a low-pressure turbine guide vane of an aeroengine. An intake measurement casing is provided at the intake end of the low-pressure turbine guide vane. An intake rectifying section is provided at the intake end of the intake measurement casing. An inlet straight pipe is provided at the intake end of the intake rectifying section. An intake converging section is provided at the intake end of the inlet straight pipe. An exhaust measurement casing is provided at the outlet end of the low-pressure turbine guide vane. The inner flow path profile of the intake converging section adopts a von Mises curve. Rectifying cascades are annularly distributed between the inner and outer casings of the intake measurement casing to change the intake direction and guide the air flow to the low-pressure turbine guide vane. The adoption of the von Mises curve for the inner flow path profile of the intake converging section can effectively improve the flow field uniformity and the axial static pressure gradient. In addition, by arranging a row of annular rectifying cascades in front of the low-pressure turbine guide vane, the intake direction can be changed, and the air flow can be guided to the low-pressure turbine guide vane, thereby ensuring that the intake direction is consistent with the engine product.

Description

Technical Field

[0001] The present invention relates to the test technology of aero-engine components, and particularly to a flow detection test section structure for a low-pressure turbine guide vane of an aero-engine, which is applicable to the flow function test of the turbine guide vane of an aero-engine. Background Art

[0002] The turbine guide vane flow function tester is mainly used to obtain the variation curves of the guide vane flow function with the total static pressure expansion ratio at the inlet and outlet and the cold air state parameters, verify the flow capacity of the guide vane, and obtain the influence law of the cold air state parameters on the guide vane flow function characteristics. Since the inlet Mach number and inlet attack angle have a direct impact on the front and rear temperatures, air flow fields, engine flow rate, power, rotational speed, fuel consumption rate, etc. of the turbine guide vane, which are related to the working stability of the engine, the matching of the compressor and the turbine, etc. Therefore, the measurement of the engine turbine guide vane function flow is an essential task, and each turbine guide vane must undergo a special flow function test before being installed and delivered to determine the qualification of the exhaust area and flow rate of the turbine guide vane.

[0003] In the prior art, there are documents disclosing technologies related to the low-pressure turbine guide vane test. For example, the publication number CN113607420A discloses a ring blowing test installation structure and test method for a low-pressure turbine guide vane, which uses a rectifying cascade to deflect the air flow by a certain angle from the axial direction, and at the same time introduces cold air into the low-pressure turbine guide vane to meet the inlet air flow angle of the low-pressure turbine guide vane and its actual flow state on the surface during the actual operation of the engine, solves the problem that the air flow directly acts on the leading edge of the low-pressure guide vane of the low-pressure turbine guide vane, improves the local separation of the air flow in the low-pressure turbine guide vane while also improving the aerodynamic performance of the low-pressure turbine guide vane, and increases the reliability of the test data.

[0004] Before the engine low-pressure turbine guide vane is installed, a flow detection test is required. This test mainly obtains the radial distribution curves of the total pressure, total temperature, static pressure, air flow angle, etc. at the inlet and outlet under different test conditions. In front of the engine low-pressure turbine guide vane is the high-pressure turbine, and the high-temperature gas flowing out of the high-pressure turbine enters the low-pressure turbine guide vane at a certain attack angle. In the past, the influence of the pre-whirl angle of the high-pressure turbine outlet air flow was not considered in the low-pressure turbine guide vane flow detection test section. Currently, there is no mature design experience for the turbine guide vane flow detection test section. The inlet converging section mostly adopts a straight cylinder design, and the flow field quality is poor. Moreover, the guide vane mostly uses axial air intake, which has a certain impact on the test results, resulting in a smaller flow detection result. Summary of the Invention

[0005] The main object of the present invention is to propose a flow detection test section structure for a low-pressure turbine guide vane of an aero-engine, aiming to solve the above technical problems.

[0006] To achieve the above object, the present invention provides a flow detection test section structure for a low-pressure turbine guide vane of an aero-engine, including a low-pressure turbine guide vane. An intake measurement casing is provided at the intake end of the low-pressure turbine guide vane, an intake rectifying section is provided at the intake end of the intake measurement casing, an inlet straight pipe is provided at the intake end of the intake rectifying section, an intake converging section is provided at the intake end of the inlet straight pipe, and an exhaust measurement casing is provided at the exhaust end of the low-pressure turbine guide vane; the inner flow path profile of the intake converging section adopts a von Mises curve; a rectifying cascade is annularly distributed between the inner and outer casings of the intake measurement casing for changing the intake direction and guiding the air flow to the low-pressure turbine guide vane.

[0007] Preferably, the design steps of the intake converging section include:

[0008] Step 1: Determine the radius H of the inlet cross-section of the converging section i and the radius H0 of the outlet cross-section of the converging section;

[0009] Step 2: Set the step size x;

[0010] Step 3: Determine the points corresponding to different step sizes according to the following formula, and perform fitting to obtain the von Mises curve part of the converging section;

[0011]

[0012] In the formula: H i —Radius of the inlet cross-section of the converging section;

[0013] H0—Radius of the outlet cross-section of the converging section;

[0014] h—Cross-section height at the axial distance x;

[0015] L is the total length of the von Mises curve part of the converging section.

[0016] Preferably, straight transition sections are integrally formed at the inlet and outlet of the intake converging section respectively.

[0017] Preferably, the roughness of the inner flow path profile of the intake converging section is not lower than Ra3.2; the length of the straight transition section is 70 mm.

[0018] Preferably, lifting lugs are provided on the intake converging section.

[0019] Preferably, the intake rectifying section includes an outer support of the intake rectifying section and a rectifying cap coaxially arranged inside the outer support of the intake rectifying section; an air intake flow path is formed by spacing the inner wall surface of the outer support of the intake rectifying section from the outer peripheral surface of the rectifying cap; the outer support of the intake rectifying section and the rectifying cap are connected by support plates.

[0020] Preferably, flange edges are respectively provided at both ends of the outer support of the intake air rectifying section. The flange edge at the intake end is connected to the inlet straight pipe, and the flange edge at the outlet end is connected to the outer casing of the intake air measuring casing. An inner support of the intake air rectifying section is arranged on the inner wall at the tail end of the fairing cap. The inner support of the intake air rectifying section is connected to the inner casing of the intake air measuring casing.

[0021] Preferably, the intake air measuring casing includes an outer casing of the intake air measuring casing and an inner casing of the intake air measuring casing coaxially arranged inside the outer casing of the intake air measuring casing. One end of the stator vane cascade is connected to the outer casing of the intake air measuring casing, and the other end is connected to the inner casing of the intake air measuring casing. An intake air flow passage is formed by arranging the outer casing of the intake air measuring casing and the inner casing of the intake air measuring casing at intervals. Total temperature and total pressure measuring points are annularly arranged on the outer peripheral surface of the outer casing of the intake air measuring casing. Two rows of inlet static pressure measuring points are annularly arranged on the inner wall surface of the inner casing of the intake air measuring casing before and after the stator vane cascade.

[0022] Preferably, after measurement by the intake air measuring casing, the total pressure before the low-pressure turbine guide vane is corrected according to the following formula:

[0023]

[0024] In the formula: P1*—total pressure before the stator vane cascade;

[0025] P2*—total pressure after the stator vane cascade;

[0026] P1—static pressure before the stator vane cascade;

[0027] P2—static pressure after the stator vane cascade;

[0028] γ = 1.4.

[0029] Preferably, the exhaust gas measuring casing includes an outer casing of the exhaust gas casing and an inner casing of the exhaust gas casing coaxially arranged inside the outer casing of the exhaust gas casing. An exhaust gas flow passage is formed by arranging the outer casing of the exhaust gas casing and the inner casing of the exhaust gas casing at intervals. An outlet fairing cap is arranged at the tail end of the inner casing of the exhaust gas casing. A plurality of exhaust gas casing support plates are arranged between the outer casing of the exhaust gas casing and the inner casing of the exhaust gas casing. Outlet static pressure measuring points are respectively arranged on the outer wall surface of the outer casing of the exhaust gas casing and the inner wall surface of the inner casing of the exhaust gas casing.

[0030] Due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0031] (1) In the present invention, the inner flow path profile of the intake converging section adopts a von Mises curve, which can effectively improve the flow field uniformity and the axial static pressure gradient, thereby improving the quality of the intake air flow field. Additionally, by arranging a row of annular straightening cascades in front of the low-pressure turbine guide vane, the intake air direction can be changed, and thus the intake attack angle can be changed, guiding the air flow to the low-pressure turbine guide vane, thereby ensuring that the intake air direction is consistent with the engine product.

[0032] (2) The present invention arranges two rows of static pressure measurement points in front of and behind the cascades of the straightening cascade to correct the total pressure in front of the low-pressure turbine guide vane, improving the accuracy of flow rate detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0034] Figure 1 It is a schematic structural diagram of the flow rate detection test section of the low-pressure turbine guide vane of an aeroengine provided by the present invention;

[0035] Figure 2 It is a schematic structural diagram of the intake converging section in the present invention;

[0036] Figure 3 It is a von Mises contraction curve diagram of the intake converging section in the present invention;

[0037] Figure 4 It is a schematic structural diagram of the intake straightening section in the present invention;

[0038] Figure 5 It is a schematic structural diagram of the intake measurement casing in the present invention;

[0039] Figure 6 It is a schematic structural diagram of the exhaust measurement casing in the present invention.

[0040] Description of the attached drawing reference numerals: 1. Inlet converging section; 101. Straight transition section; 102. Lifting lug; 2. Inlet straight pipe; 3. Inlet fairing section; 301. Fairing cap; 302. Outer support of the inlet fairing section; 303. Strut; 304. Inner support of the inlet fairing section; 4. Inlet measurement casing; 401. Total temperature and total pressure measurement point; 402. Rectifying vane cascade; 403. Outer casing of the inlet measurement casing; 404. Inlet static pressure measurement point; 405. Inner casing of the inlet measurement casing; 5. Low-pressure turbine guide vane; 6. Exhaust measurement casing; 601. Outlet static pressure measurement point; 602. Strut of the exhaust casing; 603. Outer casing of the exhaust casing; 604. Inner casing of the exhaust casing; 605. Outlet fairing cap; 7. Support platform. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0042] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0043] Combined with Figure 1 As shown, a flow detection test section structure of a low-pressure turbine guide vane of an aeroengine includes a low-pressure turbine guide vane 5. An inlet measurement casing 4 is provided at the inlet end of the low-pressure turbine guide vane 5. An inlet fairing section 3 is provided at the inlet end of the inlet measurement casing 4. An inlet straight pipe 2 is provided at the inlet end of the inlet fairing section 3. An inlet converging section 1 is provided at the inlet end of the inlet straight pipe 2. An exhaust measurement casing 6 is provided at the outlet end of the low-pressure turbine guide vane 5. The inner flow path profile of the inlet converging section 1 adopts a von Mises curve. Rectifying vane cascades 402 are annularly distributed between the inner and outer casings of the inlet measurement casing 4 for changing the inlet air direction and guiding the air flow to the low-pressure turbine guide vane 5.

[0044] The inlet converging section 1 is used to introduce the air flow in the surge tank. The inlet straight pipe 2 serves to connect the inlet converging section 1 and the inlet fairing section 3. The inlet measurement casing 4 is used for arranging the sensing parts at the inlet of the low-pressure turbine guide vane 5 and measuring the relevant aerodynamic parameters at the inlet. The exhaust measurement casing 6 is used for arranging the sensing parts at the outlet of the low-pressure turbine guide vane 5 and measuring the relevant aerodynamic parameters at the outlet.

[0045] In this embodiment, the inner flow path profile of the intake converging section 1 adopts a von Mises curve. Compared with the bicubic curve or the fifth-power curve commonly used for the contraction curve of the converging section, the von Mises curve is superior in terms of flow field uniformity and axial static pressure gradient, improving the quality of the intake air flow field. In addition, by arranging a row of annular straightening cascades 402 in front of the low-pressure turbine guide vane 5, the intake air direction can be changed, thereby changing the intake angle of attack, guiding the air flow to the low-pressure turbine guide vane 5, and ensuring that the intake air direction is consistent with the engine product.

[0046] Combined with Figure 2 and Figure 3 as shown, the design steps of the intake converging section 1 include:

[0047] Step 1: Determine the radius H of the inlet cross-section of the converging section i and the radius H0 of the outlet cross-section of the converging section;

[0048] Step 2: Set the step size x;

[0049] Step 3: Determine the points corresponding to different step sizes according to the following formula, and perform fitting to obtain the von Mises curve part of the converging section;

[0050]

[0051] where: H i —Radius of the inlet cross-section of the converging section;

[0052] H0—Radius of the outlet cross-section of the converging section;

[0053] h—Cross-section height at the axial distance x;

[0054] L is the total length of the von Mises curve part of the converging section.

[0055] Combined with Figure 2 as shown, straight transition sections 101 are integrally formed at the inlet and outlet of the intake converging section 1 respectively, avoiding flow field fluctuations at the inlet and outlet and improving the flow field quality.

[0056] In this embodiment, the entire intake converging section 1 is made of a casting, and after casting, it is further machined on a machine tool to the required precision. The roughness of the inner flow path profile of the intake converging section 1 is not lower than Ra3.2; the length of the straight transition section 101 is 70 mm, and the thickness of the intake converging section 1 is 15 mm.

[0057] Combined with Figure 2 as shown, lifting lugs 102 are provided on the intake converging section 1 to facilitate hoisting and installation by a crane.

[0058] Combined with Figure 4As shown in the figure, the intake air rectifying section 3 includes an outer support 302 of the intake air rectifying section and a rectifying cap 301 coaxially arranged inside the outer support 302 of the intake air rectifying section; a flow passage for intake air is formed by spacing the inner wall surface of the outer support 302 of the intake air rectifying section from the outer peripheral surface of the rectifying cap 301; the outer support 302 of the intake air rectifying section and the rectifying cap 301 are connected by a support plate 303. The rectifying cap 301 diverts the intake air into the annular flow passage of the test piece, and the curved surface design at the front end of the rectifying cap 301 ensures the quality of the flow field, reduces the pressure loss during the flow process, and avoids the generation of disturbances such as shock waves; the outer support 302 of the intake air rectifying section functions to connect the outer casing of the intake air measuring casing 4 and the inlet straight pipe 2, and together with the rectifying cap 301 forms a flow passage for intake air; the support plate 303 functions to connect the inner and outer supports 302 of the intake air rectifying section and the rectifying cap 301, and is required to have sufficient structural stiffness so as not to deform under the action of aerodynamic force.

[0059] Further, flange edges are respectively arranged at both ends of the outer support 302 of the intake air rectifying section. The flange edge at the intake end is connected to the inlet straight pipe 2, and the flange edge at the outlet end is connected to the outer casing of the intake air measuring casing 4; in addition, the flange edges form a frame structure after the outer support 302 of the intake air rectifying section is connected, further strengthening the rigidity of the outer support 302 of the intake air rectifying section. An inner support 304 of the intake air rectifying section is arranged on the inner wall at the tail end of the rectifying cap 301; the inner support 304 of the intake air rectifying section is connected to the inner casing of the intake air measuring casing 4. The inner support 304 of the intake air rectifying section not only functions as a connection but also as a support.

[0060] Combined with Figure 5As shown, the intake measurement casing 4 includes an outer casing 403 of the intake measurement casing and an inner casing 405 of the intake measurement casing coaxially arranged inside the outer casing 403 of the intake measurement casing. One end of the guide vane cascade 402 is connected to the outer casing 403 of the intake measurement casing, and the other end is connected to the inner casing 405 of the intake measurement casing. A flow passage is formed by arranging the outer casing 403 of the intake measurement casing and the inner casing 405 of the intake measurement casing at intervals, and the surface roughness Ra of the flow passage is 1.6. Total temperature and total pressure measurement points 401 are arranged annularly on the outer circumferential surface of the outer casing 403 of the intake measurement casing for measuring the total temperature and total pressure of the outer wall surface. The total temperature and total pressure measurement points 401 are arranged at the axial projection position of 1.5 times the chord length of the mean diameter of the guide vane cascade 402 blades in the axial direction from the leading edge of the guide vane cascade 402. Since there is a certain pressure loss in the air flow passing through the guide vane cascade 402, two rows of inlet static pressure measurement points 404 are arranged annularly on the inner wall surface of the inner casing 405 of the intake measurement casing in front of and behind the guide vane cascade 402 for measuring the static pressure of the inner wall surface and correcting the total pressure loss generated by the circumferential guide vane cascade 402 structure. The axial direction of the inlet static pressure measurement points 404 in front of the guide vane cascade 402 is consistent with the probe air inlet of the total temperature and total pressure measurement points 401, and the inlet static pressure measurement points 404 behind the guide vane cascade 402 are as close as possible to the low-pressure turbine guide vane 5. The inner casing 405 of the intake measurement casing is used to connect the test piece drum structure and should have sufficient structural stiffness to ensure the stability of the test piece during the test.

[0061] In this embodiment, after measuring with the intake measurement casing 4, the total pressure in front of the low-pressure turbine guide vane 5 is corrected according to the following formula:

[0062]

[0063] In the formula: P1*—total pressure in front of the guide vane cascade;

[0064] P2*—total pressure behind the guide vane cascade;

[0065] P1—static pressure in front of the guide vane cascade;

[0066] P2—static pressure behind the guide vane cascade;

[0067] γ = 1.4.

[0068] Combined with Figure 6As shown, the exhaust measurement casing 6 includes an outer exhaust casing 603 and an inner exhaust casing 604 coaxially arranged inside the outer exhaust casing 603; an exhaust flow passage is formed by arranging a gap between the outer exhaust casing 603 and the inner exhaust casing 604, and the surface roughness Ra of the exhaust flow passage is 1.6; an outlet fairing 605 is arranged at the tail end of the inner exhaust casing 604; a plurality of exhaust casing support plates 602 are arranged between the outer exhaust casing 603 and the inner exhaust casing 604; outlet static pressure measurement points 601 are respectively arranged on the outer wall surface of the outer exhaust casing 603 and the inner wall surface of the inner exhaust casing 604 for measuring the outlet static pressure, and the axial distance of the outlet static pressure measurement point 601 from the trailing edge of the blade of the low-pressure turbine guide vane 5 is 1.5 times the axial projection of the chord length of the blade mid-diameter. The exhaust casing support plates 602 are used to support the inner and outer casings of the exhaust measurement casing 6 to ensure stability, and are welded at a certain angle according to the exhaust gas flow angle to avoid the influence of shock waves at the outlet. The outer exhaust casing 603 is used to connect the outlet of the outer casing of the test piece and should have sufficient structural stiffness to ensure the stability of the test piece during the test. The inner exhaust casing 604 is used to connect the drum structure of the test piece and should have sufficient structural stiffness to ensure the stability of the test piece during the test. The trailing edge profile of the outlet fairing 605 is designed as a curved surface, so that the exhaust flow passage shows an expanding trend to ensure smooth exhaust.

[0069] Combined with Figure 1 As shown, the structure of the flow detection test section of the low-pressure turbine guide vane of an aeroengine further includes a support platform 7. Mounting seats are arranged on the support platform 7 and are respectively connected to the inlet straight pipe 2 and the intake rectifying section 3. The support platform 7 plays a role in supporting the entire test section.

[0070] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or any direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A flow detection test section structure for a low-pressure turbine guide vane of an aero-engine, comprising a low-pressure turbine guide vane (5), characterized in that: An intake measurement casing (4) is provided at the intake end of the low-pressure turbine guide vane (5). An intake rectifying section (3) is provided at the intake end of the intake measurement casing (4). An inlet straight pipe (2) is provided at the intake end of the intake rectifying section (3). An intake converging section (1) is provided at the intake end of the inlet straight pipe (2). An exhaust measurement casing (6) is provided at the outlet end of the low-pressure turbine guide vane (5); The internal flow path profile of the intake converging section (1) adopts a von Mises curve; Rectifying cascades (402) are annularly distributed between the inner and outer casings of the intake measurement casing (4) to change the intake direction and guide the air flow to the low-pressure turbine guide vane (5); Straight transition sections (101) are integrally formed at the inlet and outlet of the intake converging section (1) respectively; The intake measurement casing (4) includes an outer casing of the intake measurement casing (403) and an inner casing of the intake measurement casing (405) coaxially arranged inside the outer casing of the intake measurement casing (403). One end of the rectifying cascade (402) is connected to the outer casing of the intake measurement casing (403), and the other end is connected to the inner casing of the intake measurement casing (405). An intake flow path is formed by an interval arrangement between the outer casing of the intake measurement casing (403) and the inner casing of the intake measurement casing (405). Total temperature and total pressure measurement points (401) are annularly arranged on the outer peripheral surface of the outer casing of the intake measurement casing (403). Two rows of inlet static pressure measurement points (404) are annularly arranged on the inner wall surface of the inner casing of the intake measurement casing (405) before and after the rectifying cascade (402); The exhaust measurement casing (6) includes an outer casing of the exhaust casing (603) and an inner casing of the exhaust casing (604) coaxially arranged inside the outer casing of the exhaust casing (603). An exhaust flow path is formed by an interval arrangement between the outer casing of the exhaust casing (603) and the inner casing of the exhaust casing (604). An outlet rectifying cap (605) is provided at the tail end of the inner casing of the exhaust casing (604). A plurality of exhaust casing support plates (602) are provided between the outer casing of the exhaust casing (603) and the inner casing of the exhaust casing (604). Outlet static pressure measurement points (601) are provided on the outer wall surface of the outer casing of the exhaust casing (603) and the inner wall surface of the inner casing of the exhaust casing (604) respectively; The design steps of the intake converging section (1) include: Step 1: Determine the inlet cross-sectional radius H of the converging section i and the outlet cross-sectional radius H0 of the converging section; Step two: Set the step size x; Step three: Determine the points corresponding to different step sizes according to the following formula, and the von Mises curve part of the converging section can be obtained by fitting; ； Where: H i — Radius of the inlet cross-section of the converging section; H0—Radius of the outlet section of the converging section; h—Section height at the axial distance x; , L is the total length of the part of the Vickers curve in the converging section; After measurement by the intake measurement casing (4), the total pressure in front of the low-pressure turbine guide vane (5) is corrected according to the following formula: In the formula: P1*—Total pressure in front of the rectifying cascade; P2*—Total pressure behind the rectifying cascade; P1—Static pressure in front of the rectifying cascade; P2—Static pressure behind the rectifying cascade; γ = 1.

4.

2. The structure of the flow detection test section of the low-pressure turbine guide vane of an aeroengine according to claim 1, wherein: The roughness of the internal flow path profile of the intake converging section (1) is not lower than Ra3.

2. The length of the straight transition section (101) is 70 mm.

3. The flow detection test section structure of the low-pressure turbine guide vane of an aero-engine according to claim 1, characterized in that: Lifting lugs (102) are provided on the intake converging section (1).

4. The flow detection test section structure of the low-pressure turbine guide vane of an aeroengine according to claim 1, characterized in that: The intake air rectifying section (3) includes an outer support (302) of the intake air rectifying section and a rectifying cap (301) coaxially arranged inside the outer support (302) of the intake air rectifying section; An air inlet flow passage is formed by arranging the inner wall surface of the outer support (302) of the intake air rectifying section and the outer peripheral surface of the rectifying cap (301) at intervals; the outer support (302) of the intake air rectifying section and the rectifying cap (301) are connected by a support plate (303).

5. The structure of the flow detection test section of the low-pressure turbine guide vane of an aeroengine as described in claim 4, characterized in that: Flange edges are respectively arranged at both ends of the outer support (302) of the intake air rectifying section. The flange edge at the air inlet end is connected to the inlet straight pipe (2), and the flange edge at the air outlet end is connected to the outer casing of the intake air measuring casing (4); an inner support (304) of the intake air rectifying section is arranged on the inner wall at the tail end of the rectifying cap (301); the inner support (304) of the intake air rectifying section is connected to the inner casing of the intake air measuring casing (4).

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