A test system and method for accurately measuring the aerodynamic forces of a ducted fan as a whole and multiple components

Abstract

This invention provides a test system and method for precise measurement of the overall and multi-component aerodynamics of a ducted fan, including a static duct component, a rotating component, a power component, a support component, and a measurement component. The measurement component includes a thrust-torque sensor, a first box balance, and a second box balance. This invention is applied to wind tunnel tests for precise testing of the propulsion performance of high-power ducted fans in aircraft. By designing a dual-box balance with a thrust-torque sensor, the aerodynamic performance of the ducted fan as a whole and its multiple components can be accurately obtained. This facilitates a comprehensive study of the ducted fan performance and the contribution and influence of each component on the overall performance, thereby further promoting the improvement of related design methods and levels. In addition, through improvements to the test system, nonlinear aerodynamic interference caused by the model support structure can be effectively reduced, improving the accuracy of ducted fan performance test results.

Description

Technical Field

[0001] This invention belongs to the field of experimental aerodynamics technology, specifically relating to an experimental system and method for accurate measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components. Background Technology

[0002] As a core component for propulsion or attitude control in low-speed aircraft, ducted fans require aerodynamic performance testing to ensure their operational reliability. Currently, wind tunnel testing is the most reliable method for verifying ducted fan performance.

[0003] In the existing technology, the wind tunnel test method for ducted fan performance generally adopts a single balance to test the overall aerodynamic performance of the ducted fan. This method has the following shortcomings: (1) The measured performance parameters of the ducted fan are relatively few, which is not conducive to the study of the flow mechanism and performance optimization design of the ducted fan; (2) When conducting the wind tunnel test of ducted fan performance, the nonlinear aerodynamic interference caused by the model support structure is large, which leads to a certain deviation in the test results of the ducted fan performance and reduces the accuracy of the test results of the ducted fan performance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a test system and method for accurate measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components, which can effectively solve the above-mentioned problems.

[0005] The technical solution adopted in this invention is as follows:

[0006] The present invention provides a test system for accurate measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components, including a static duct component (100), a rotating component (200), a power component (300), a support component (400), and a measurement component (500);

[0007] The support assembly (400) includes a test platform (401), a duct base (402), and a test system base (403); the measurement assembly (500) includes a thrust torque sensor (501), a first box balance (502), and a second box balance (503);

[0008] The test system base (403) is vertically positioned above the ground; the first box balance (502) is mounted on the top of the test system base (403); the test platform (401) is fixedly mounted on the top of the first box balance (502); the second box balance (503) is mounted inside the test platform (401); the duct static component (100) is fixedly mounted on the top of the second box balance (503) via the duct base (402); the rotating component (200) is supported and mounted on the top of the test platform (401), and one end of the rotating component (200) is connected to the power component (300) via the thrust torque sensor (501), and the rotating component (200) is driven to rotate by the power component (300).

[0009] Preferably, the duct static assembly (100) includes a duct (101), a fairing arm (102), and a nacelle (103);

[0010] The duct base (402) is fixedly installed at the bottom of the duct (101), and the duct base (402) is fixed on the top of the second box balance (503); the nacelle (103) is horizontally arranged at the axial center of the duct (101), and a plurality of rectifier arms (102) are radially distributed on the duct (101). One end of the rectifier arm (102) is fixed to the inner wall of the duct (101), and the other end is fixed to the outer wall of the nacelle (103). Therefore, the nacelle (103) is suspended and fixed by the duct (101) and the rectifier arm (102).

[0011] Preferably, the rotating assembly (200) includes a rotating shaft (201), blades (202), and a hub (203);

[0012] The rotating shaft (201) is horizontally positioned through the cavity of the nacelle (103) and the center of the duct (101). One end of the rotating shaft (201) is connected to the power assembly (300) via the thrust torque sensor (501), and the power assembly (300) drives the rotating shaft (201) to rotate. Inside the duct (101) and on one side of each of the rectifier arms (102), a plurality of blades (202) are radially distributed along the duct (101). One end of each blade (202) has a gap with the inner wall of the duct (101), and the other end of each blade (202) is fixed to the rotating shaft (201) via the hub (203). When the rotating shaft (201) rotates, the hub (203) drives the blades (202) to rotate synchronously.

[0013] Preferably, the blade (202) is an adjustable blade with a pitch angle.

[0014] Preferably, the propeller hub (203) includes a front block (2031), a rear block (2032), a hub fastening bolt (2033), and a hub fixing nut (2034);

[0015] The rotating shaft (201) is machined into a stepped shaft at the position where the propeller hub (203) is installed, and an external thread is machined on one side of the stepped shaft;

[0016] The front hub block (2031) and the rear hub block (2032) are sequentially fitted onto the outside of the stepped shaft. Multiple grooves are formed circumferentially on opposite sides of the front hub block (2031) and the rear hub block (2032). The grooves of the front hub block (2031) and the rear hub block (2032) align to form a stepped cylindrical groove that matches the root of the blade (202). After the root of the blade (202) is embedded in the stepped cylindrical groove, it is secured by the hub fastening bolts (203... 3) Secure the front hub block (2031) and the rear hub block (2032) to achieve the fixation between the blade (202) and the hub (203); on the rear side of the rear hub block (2032), screw the hub fixing nut (2034) along the external thread of the stepped shaft to secure the front hub block (2031) and the rear hub block (2032) against the shoulder of the stepped shaft, thereby achieving the fixation between the hub (203) and the shaft (201).

[0017] Preferably, the rotating assembly (200) further includes a propeller cap (204) and a propeller cap fixing screw (205);

[0018] The propeller cap (204) is fitted over the outside of the rotating shaft (201). One end of the rotating shaft (201) is fixed to the propeller hub (203) by the propeller cap fixing screw (205). The propeller cap (204) and the nacelle (103) are located on both sides of the propeller hub (203).

[0019] Both the propeller cap (204) and the nacelle (103) have a shape in which their diameter gradually decreases along the direction away from the center of the duct (101).

[0020] Preferably, the support assembly (400) further includes: a bearing support (404), a bearing-sensor support (405), and a motor support (406); the bearing support (404), the bearing-sensor support (405), and the motor support (406) are fixedly installed on the test platform (401).

[0021] The rotating assembly (200) further includes: a first bearing (206), a second bearing (207), a first diaphragm coupling (208), and a second diaphragm coupling (209);

[0022] The first bearing (206) is mounted on the end of the rotating shaft (201) away from the thrust torque sensor (501). The first bearing (206) is disposed on the bearing support (404) and is supported by the bearing support (404).

[0023] After the second bearing (207) is installed on one end of the rotating shaft (201) near the thrust torque sensor (501), the end of the rotating shaft (201) is connected to one end of the thrust torque sensor (501) through the first diaphragm coupling (208); the other end of the thrust torque sensor (501) is connected to the output end of the power assembly (300) through the second diaphragm coupling (209).

[0024] The second bearing (207) and the thrust torque sensor (501) are disposed on the bearing-sensor support (405), and the bearing-sensor support (405) supports the second bearing (207) and the thrust torque sensor (501).

[0025] The power assembly (300) is disposed on the motor support (406), and the power assembly (300) is supported by the motor support (406).

[0026] Preferably, the power assembly (300) includes a drive motor (301) and a motor fairing (302) for reducing aerodynamic interference of the drive motor (301);

[0027] The output shaft of the drive motor (301), the thrust torque sensor (501), and the rotating shaft (201) are coaxially arranged.

[0028] Preferably, the first box balance (502) and the second box balance (503) are arranged alternately in the vertical direction.

[0029] The present invention also provides a test method for a test system for accurate measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components, comprising the following steps:

[0030] Step S1: Determine the test conditions for this test, including: the pitch angle of the blade (202), the rotational speed of the power unit (300), and the incoming wind speed;

[0031] Step S2: Conduct a ducted fan wind tunnel test according to the test conditions; and during the ducted fan wind tunnel test, the thrust torque sensor (501), the first box balance (502), and the second box balance (503) collect test data in real time.

[0032] Step S3 involves analyzing the collected test data to determine the overall aerodynamic performance parameters and component aerodynamic performance parameters of the ducted fan in this test, specifically including:

[0033] Step S3.1, establish the coordinate system of the second box balance (503) as follows: take the center of the second box balance (503) as the origin, take the vertical upward as the positive Y-axis, take the horizontal direction towards the power component (300) as the positive X-axis, and determine the Z-axis according to the right-hand rule, thereby establishing the coordinate system of the second box balance (503);

[0034] The coordinate system of the first box balance (502) is established as follows: with the center of the first box balance (502) as the origin, the vertical upward direction as the positive Y-axis, the horizontal direction towards the power component (300) as the positive X-axis, and the Z-axis determined according to the right-hand rule, thereby establishing the coordinate system of the first box balance (502);

[0035] Step S3.2, the second box balance (503) collects the force and torque along its three coordinate axes, which are: force F XA F YA F ZA Torque MF XA MF YA MF ZA ;

[0036] The first box balance (502) collects the force and torque along its three coordinate axes, which are: force F XB F YB F ZB Torque MF XB MF YB MF ZB ;

[0037] The thrust torque sensor (501) collects the axial thrust T0 and power P0;

[0038] Step S3.3, the overall aerodynamic performance parameters include: total thrust T, shaft power P, efficiency η1 when the incoming air velocity is greater than 0, and force efficiency η2 when the incoming air velocity is 0, which are determined by the following formulas:

[0039]

[0040] P = P0

[0041]

[0042] Where: V is the incoming air velocity; η2 is the force efficiency when the incoming air velocity is 0, specifically the ducted fan propulsion efficiency under static thrust.

[0043] The aerodynamic performance parameters of the components include blade thrust, duct thrust, and fairing arm thrust; among which, blade thrust is equal to the axial thrust T0 collected by the thrust torque sensor (501); duct thrust and fairing arm thrust are equal to the force F collected by the second box balance (503). XA .

[0044] The experimental system and method for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components provided by this invention have the following advantages:

[0045] This invention provides an experimental system and method for precise measurement of the overall and multi-component aerodynamics of a ducted fan. It is applied to wind tunnel tests for precise propulsion performance testing of high-power ducted fans in aircraft. By designing a dual-box balance with thrust and torque sensors, the aerodynamic performance of the ducted fan as a whole and its multiple components can be accurately acquired, providing more performance parameters. This facilitates a comprehensive study of ducted fan performance and the contribution and influence of each component on the overall performance, thereby further promoting the improvement of related design methods and levels. Furthermore, improvements to the experimental system effectively reduce nonlinear aerodynamic interference caused by the model support structure, improving the accuracy of ducted fan performance test results. Attached Figure Description

[0046] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0047] Figure 1 A schematic diagram of the overall structure of the test system for precise measurement of the aerodynamic forces of the entire ducted fan and its multiple components provided by the present invention;

[0048] Figure 2 An assembly diagram of a portion of the rotating component and the duct static component provided by the present invention;

[0049] Figure 3 An exploded view of a portion of the structure of the rotating component provided by the present invention;

[0050] Figure 4 Assembly diagram of the shaft, blades and hub provided for this invention;

[0051] Figure 5 A perspective view of a portion of the structure of the support assembly provided by the present invention;

[0052] Figure 6 This is a schematic diagram of the coordinate system of two box balances in an embodiment of the present invention.

[0053] In the picture:

[0054] 100. Duct static assembly; 101. Duct; 102. Rectifier arm; 103. Nacelle;

[0055] 200. Rotating assembly; 201. Shaft; 202. Blade; 203. Hub; 2031. Front hub block; 2032. Rear hub block; 2033. Hub fastening bolt; 2034. Hub fixing nut; 204. Hub cap; 205. Hub cap fixing screw; 206. First bearing; 207. Second bearing; 208. First diaphragm coupling; 209. Second diaphragm coupling;

[0056] 300. Power assembly; 301. Drive motor; 302. Motor fairing;

[0057] 400. Support assembly; 401. Test platform; 402. Duct base; 403. Test system base; 404. Bearing support; 405. Bearing-sensor support; 406. Motor support;

[0058] 500. Measuring components; 501. Thrust and torque sensor; 502. First cassette balance; 503. Second cassette balance. Detailed Implementation

[0059] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0060] This invention provides an experimental system and method for precise measurement of the overall and multi-component aerodynamics of a ducted fan. It is applied to wind tunnel tests for precise propulsion performance testing of high-power ducted fans in aircraft. By designing a dual-box balance with thrust and torque sensors, the aerodynamic performance of the ducted fan as a whole and its multiple components can be accurately acquired, providing more performance parameters. This facilitates a comprehensive study of ducted fan performance and the contribution and influence of each component on the overall performance, thereby further promoting the improvement of related design methods and levels. Furthermore, improvements to the experimental system effectively reduce nonlinear aerodynamic interference caused by the model support structure, improving the accuracy of ducted fan performance test results.

[0061] See Figures 1-6 The present invention provides a test system for accurate measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components, including a static duct component 100, a rotating component 200, a power component 300, a support component 400, and a measurement component 500.

[0062] The support assembly 400 includes a test platform 401, a duct base 402, and a test system base 403; the measurement assembly 500 includes a thrust torque sensor 501, a first box balance 502, and a second box balance 503.

[0063] The test system base 403 is vertically positioned above the ground; a first box balance 502 is installed on the top of the test system base 403; a horizontally positioned test platform 401 is fixedly installed on the top of the first box balance 502; a second box balance 503 is installed inside the test platform 401; a duct static component 100 is fixedly installed on the top of the second box balance 503 via a duct base 402; a rotating component 200 is supported and installed on the top of the test platform 401, and one end of the rotating component 200 is connected to a power component 300 via a thrust torque sensor 501, and the power component 300 drives the rotating component 200 to rotate.

[0064] As a preferred embodiment, the first box balance 502 and the second box balance 503 are arranged alternately in the vertical direction.

[0065] The following is a detailed description of the duct static component 100, the rotating component 200, the power component 300, and the support component 400:

[0066] (I) Duct static component 100:

[0067] The duct static assembly 100 includes a duct 101, a fairing arm 102, and a nacelle 103;

[0068] A duct base 402 is fixedly installed at the bottom of the duct 101, and the duct base 402 is fixed on the top of the second box balance 503; a nacelle 103 is horizontally arranged at the axial center of the duct 101, and multiple rectifier arms 102 are radially distributed on the duct 101. One end of the rectifier arm 102 is fixed to the inner wall of the duct 101, and the other end is fixed to the outer wall of the nacelle 103. Therefore, the nacelle 103 is suspended and fixed by the duct 101 and the rectifier arms 102.

[0069] (II) Rotating assembly 200:

[0070] The rotating assembly 200 includes a shaft 201, a blade 202, and a hub 203;

[0071] The rotating shaft 201 is horizontally positioned through the cavity of the nacelle 103 and the center of the duct 101. One end of the rotating shaft 201 is connected to the power assembly 300 via the thrust torque sensor 501, and the power assembly 300 drives the rotating shaft 201 to rotate. Inside the duct 101, and on one side of each rectifier arm 102, multiple blades 202 are radially distributed along the duct 101. One end of each blade 202 has a gap with the inner wall of the duct 101, and the other end of each blade 202 is fixed to the rotating shaft 201 via a hub 203. When the rotating shaft 201 rotates, the hub 203 drives the blades 202 to rotate synchronously.

[0072] In this invention, the blade 202 is an adjustable pitch angle blade, which allows the pitch angle to be changed without disassembling components. This facilitates testing at various pitch angles and allows for comparison of test results at different pitch angles. Combined with... Figures 2-4 The propeller hub 203 includes a front propeller hub block 2031, a rear propeller hub block 2032, a propeller hub fastening bolt 2033, and a propeller hub fixing nut 2034.

[0073] The rotating shaft 201 is machined into a stepped shaft at the position where the propeller hub 203 is installed, and an external thread is machined on one side of the stepped shaft;

[0074] The front hub block 2031 and the rear hub block 2032 are sequentially fitted onto the outside of the stepped shaft. Multiple grooves are provided circumferentially on opposite sides of the front hub block 2031 and the rear hub block 2032. The grooves of the front hub block 2031 and the rear hub block 2032 align to form a stepped cylindrical groove that matches the root of the blade 202. After the root of the blade 202 is embedded in the stepped cylindrical groove, the front hub block 2031 and the rear hub block 2032 are secured by the hub fastening bolts 2033, thereby fixing the blade 202 and the hub 203. On the rear side of the rear hub block 2032, the hub fixing nut 2034 is screwed along the external thread of the stepped shaft, causing the front hub block 2031 and the rear hub block 2032 to be secured against the shoulder of the stepped shaft, thereby fixing the hub 203 and the shaft 201.

[0075] Therefore, when it is necessary to adjust the pitch angle of the blade 202, simply loosen the hub fastening bolt 2033 to rotate the blade 202 and adjust its pitch angle. Then tighten the hub fastening bolt 2033.

[0076] In this invention, the rotating assembly 200 also includes a propeller cap 204 and a propeller cap fixing screw 205; the propeller cap 204 is fitted around the outside of the rotating shaft 201, one end of the rotating shaft 201 is fixed to the propeller hub 203 by the propeller cap fixing screw 205, and the propeller cap 204 and the nacelle 103 are respectively located on both sides of the propeller hub 203.

[0077] In practice, the propeller cap 204 can be CNC machined from 7075 aluminum alloy to reduce weight; the shaft 201 and the hub 203 can be CNC machined from 30CrMnSiA steel and heat-treated to improve strength. Both the propeller cap 204 and the nacelle 103 have a shape in which their diameter gradually decreases along the direction away from the center of the duct 101. This design is a hydrodynamic design that can reduce aerodynamic drag and improve the accuracy of the aerodynamic performance parameters obtained from the test.

[0078] (III) Bracket Assembly 400:

[0079] The support assembly 400 also includes: a bearing support 404, a bearing-sensor support 405, and a motor support 406; the bearing support 404, the bearing-sensor support 405, and the motor support 406 are fixedly installed on the test platform 401 respectively; in specific implementation, the support assembly 400 is formed by welding 45# steel plate.

[0080] The rotating assembly 200 also includes: a first bearing 206, a second bearing 207, a first diaphragm coupling 208, and a second diaphragm coupling 209;

[0081] The first bearing 206 is mounted on the end of the rotating shaft 201 away from the thrust torque sensor 501. The first bearing 206 is set on the bearing support 404 and is supported by the bearing support 404.

[0082] After the second bearing 207 is installed at one end of the rotating shaft 201 near the thrust torque sensor 501, the end of the rotating shaft 201 is connected to one end of the thrust torque sensor 501 through the first diaphragm coupling 208; the other end of the thrust torque sensor 501 is connected to the output end of the power assembly 300 through the second diaphragm coupling 209.

[0083] The second bearing 207 and the thrust torque sensor 501 are disposed on the bearing-sensor support 405, and the bearing-sensor support 405 supports the second bearing 207 and the thrust torque sensor 501.

[0084] The power assembly 300 is mounted on the motor support 406, and the motor support 406 supports the power assembly 300.

[0085] In practical applications, the first bearing 206 and the second bearing 207 at both ends of the rotating shaft 201 can be flangeless cylindrical roller bearings. These bearings do not restrict the axial displacement of the rotating shaft 201, ensuring axial freedom, thereby improving the accuracy of the torque sensor 501 in measuring the blade thrust.

[0086] In this application, the thrust torque sensor 501 is arranged between the power assembly 300 and the rotating shaft 201 to directly measure the blade thrust. The thrust torque sensor 501 is positioned on top of the bearing-sensor support 405, with one end connected to the motor shaft of the power assembly 300 via a flange, and the other end connected to one end of the rotating shaft 201 via a flange. Furthermore, diaphragm couplings are installed at both ends of the thrust torque sensor 501 to compensate for coaxiality tolerances between the thrust torque sensor 501, the rotating shaft 201, and the output shaft of the power assembly 300, thus protecting the thrust torque sensor 501.

[0087] (iv) Power Components 300:

[0088] The power assembly 300 includes a drive motor 301 and a motor fairing 302 for reducing aerodynamic interference of the drive motor 301;

[0089] The output shaft of the drive motor 301, the thrust torque sensor 501, and the rotating shaft 201 are coaxially arranged.

[0090] This invention also provides a test method for a test system for accurate measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components, comprising the following steps:

[0091] Step S1: Determine the test conditions for this experiment, including: the pitch angle of the blade 202, the rotational speed of the power unit 300, and the incoming wind speed.

[0092] Step S2: Conduct a ducted fan wind tunnel test according to the test conditions; and during the ducted fan wind tunnel test, the thrust torque sensor 501, the first box balance 502, and the second box balance 503 collect test data in real time.

[0093] Step S3 involves analyzing the collected test data to determine the overall aerodynamic performance parameters and component aerodynamic performance parameters of the ducted fan in this test. Specifically, this includes:

[0094] Step S3.1: Establish the coordinate system of the second box balance 503 as follows: take the center of the second box balance 503 as the origin, take the vertical upward as the positive Y-axis, take the horizontal direction towards the power component 300 as the positive X-axis, and determine the Z-axis according to the right-hand rule, thereby establishing the coordinate system of the second box balance 503.

[0095] The coordinate system of the first box balance 502 is established as follows: with the center of the first box balance 502 as the origin, the vertical upward direction as the positive Y-axis, the horizontal direction towards the power component 300 as the positive X-axis, and the Z-axis determined according to the right-hand rule, thus establishing the coordinate system of the first box balance 502.

[0096] Step S3.2, the second box balance 503 collects the force and torque along its three coordinate axes, which are: force F XA F YA F ZA Torque MF XA MF YA MF ZA ;

[0097] The first box balance 502 collected the force and torque along its three coordinate axes, which are: force F XB F YB F ZB Torque MF XB MF YB MF ZB ;

[0098] The thrust-torque sensor 501 collects the axial thrust T0 and power P0.

[0099] Step S3.3, the overall aerodynamic performance parameters include: total thrust T, shaft power P, efficiency η1 when the incoming air velocity is greater than 0, and force efficiency η2 when the incoming air velocity is 0, which are determined by the following formulas:

[0100]

[0101] P = P0

[0102]

[0103] Where: V is the incoming air velocity; η2 is the force efficiency when the incoming air velocity is 0, specifically the ducted fan propulsion efficiency under static thrust.

[0104] The aerodynamic performance parameters of the components include blade thrust, duct thrust, and fairing arm thrust; wherein, blade thrust is equal to the axial thrust T0 collected by thrust torque sensor 501; duct thrust and fairing arm thrust are equal to the force F collected by second box balance 503. XA .

[0105] The following is an example:

[0106] This invention provides a test system and method for accurate measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components. Applied to wind tunnel tests of ducted fan models, the test system operated well during the wind tunnel tests, and the test data were accurate and reliable. The following describes the specific implementation of this invention using a ground static thrust test of a certain type of ducted fan model as an example.

[0107] (I) Experimental Model

[0108] The main body of the experimental ducted fan model includes a static duct component 100, a rotating component 200, a power component 300, a support component 400, and a measurement component 500. The static duct component 100 includes a duct 101, a rectifier arm 102, and a nacelle 103; the rotating component 200 includes a shaft 201, blades 202, a hub 203, and a blade cap 204. The duct 101, rectifier arm 102, and nacelle 103 are made of materials such as carbon steel, fiberglass, and beech wood; the blades 202 are six-bladed and made of 7075 aluminum alloy, with a variable pitch angle. The ducted fan experimental model is shown below. Figure 1 As shown.

[0109] The measuring assembly 500 includes a thrust torque sensor 501, a first cassette balance 502, and a second cassette balance 503.

[0110] The first box balance 502 and the second box balance 503 are six-component box balances. The first box balance 502 is a TP1201 six-component box balance, and the second box balance 503 is a TP2001 six-component box balance. The first box balance 502 is used to measure the overall aerodynamic performance parameters of the ducted fan, and the second box balance 503 is used to measure the aerodynamic performance parameters of the components.

[0111] The thrust-torque sensor 501 is a custom-designed product capable of simultaneously measuring thrust and torque at one end. It employs the strain gauge principle; when the strain shaft is subjected to force and undergoes slight deformation, the resistance of the strain gauge attached to the shaft changes accordingly. This change in resistance is converted into a voltage signal change via a measuring bridge for measurement. The acquisition and display of the voltage signal from the thrust-torque sensor 501 are performed by the accompanying measuring instrument.

[0112] Because the thrust torque sensor 501 has high requirements for the coaxiality of the rotating shaft, diaphragm couplings are connected to both ends of the thrust torque sensor 501 to prevent damage. In this experiment, KTS93-24-F88 diaphragm couplings are used, with the interface customized as a keyway on one end and a flange on the other.

[0113] The drive motor 301 of the power assembly 300 is a high power density motor, specifically a 100kW high power density motor, used to drive the blade 202 to rotate.

[0114] (II) Experimental Preparation and Process

[0115] The preparatory work before the test includes: test model inspection and acceptance, dynamic / static balance test of rotating component 202, assembly and debugging test of duct static component 100, rotating component 200, power component 300 and support component 400, and static loading test of thrust torque sensor 501, first box balance 502 and second box balance 503.

[0116] The test included repeatability accuracy testing and propulsion performance testing of a ducted fan model under specified operating conditions.

[0117] Test Model Inspection and Acceptance: Before testing, key dimensions and profiles of the test model need to be inspected. For example, the propeller blades need to be inspected by measuring mass, length, and root diameter, and by using a profile template; the ductwork needs to be inspected by measuring chord length, inner diameter, and tail diameter, and by using a profile template; and the fairing arm needs to be inspected by using a profile template. The machining accuracy of the wind tunnel test model needs to meet the requirements of GJB180A-2006 "Design Guidelines for Low-Speed ​​Wind Tunnel Aircraft Models".

[0118] Rotating Component Dynamic / Static Balance Test: To ensure the safety of the test, high-speed rotating components must pass a dynamic / static balance test before being put into use. This test is performed on a dynamic balancing test bench. In this test, the rotating component 200 includes a shaft 201, blades 202, a hub 203, and a cap 204. The general steps of the dynamic / static balance test are as follows: After assembling the rotating component 200 into a whole, fix it on the dynamic balancing test bench. Start the test bench to make the rotating component 200 rotate. The test bench will display the dynamic imbalance and angle of the rotating component 200. At this point, it is necessary to add counterweights or reduce weight at appropriate locations to reduce the dynamic imbalance. Through repeated adjustments, the dynamic balance quality of the rotating component 200 can be improved, thereby reducing the vibration of the rotating component 200 during the test.

[0119] The test model and bench assembly and debugging test: The debugging test aims to ensure that the components of the test system can be assembled without interference and that the test system can operate smoothly. Since there are multiple connection structures between the end of the shaft and the drive motor in this test system, the focus of the debugging is to ensure the coaxiality of each section. Finally, the test system needs to pass several test runs to reach the highest speed required for the test. Only when the test system is operating normally can the formal test be carried out.

[0120] Static loading test of thrust torque sensor 501, first box balance 502, and second box balance 503: Static loading of thrust torque sensor 501, first box balance 502, and second box balance 503 is a means to ensure that the readings of each thrust torque sensor 501, first box balance 502, and second box balance 503 are normal before the formal test. The specific operation is as follows: with the test system off, several standard weights are added to each thrust torque sensor 501, first box balance 502, and second box balance 503 in each direction, and the readings are checked on the data acquisition system. Typically, the first box balance 502 and second box balance 503 need to be statically loaded using a three-axis method, while the thrust torque sensor 501 needs to be tested with both thrust and torque applied.

[0121] The test was conducted using the test system and method for precise measurement of the aerodynamic forces of the ducted fan as a whole and its multiple components provided by this invention.

[0122] (III) Error Analysis of Experimental Data

[0123] Wind tunnel testing accuracy, also known as repeatability accuracy, is assessed by repeatedly conducting tests under the same conditions, collecting test data, and calculating the root mean square (RMS) of the data. In engineering applications, the RMS error of wind tunnel tests is typically required to be ≤1%. In this test, the repeatability test was repeated 7 times, and the RMS error of the thrust coefficient was 0.21%, and the RMS error of the shaft power coefficient was 0.14%, achieving an excellent level in the industry.

[0124] (IV) Conclusion

[0125] This ducted fan testing system has successfully completed multiple ducted fan model wind tunnel tests. During the tests, the system operated normally, and the box balances and thrust torque sensors successfully measured the aerodynamic forces of the whole and its components, successfully obtaining test data on the aerodynamic performance of the ducted fan model as a whole and its components. The accuracy of the test results met the requirements.

[0126] This invention provides a test system and method for accurate measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components, which has the following advantages:

[0127] 1. The ducted fan test system and method places the thrust torque sensor between the motor output end and the shaft. The measured blade thrust test value is not affected by the aerodynamic interference of the support and the transmission of force, effectively reducing the nonlinear interference problem of the test bench.

[0128] 2. This ducted fan test system and method can accurately measure the overall performance parameters of the ducted fan model, such as total thrust, shaft power, and efficiency, as well as the aerodynamic parameters of components such as blade thrust, duct and rectifier arm thrust. It can obtain the mutual influence between components and their contribution to the overall performance. The test data can provide support for the study of complex interference flow mechanisms of multi-component ducted fans and the coupled design of multi-component ducted fans for high-performance fans, thereby improving the design level.

[0129] This invention supports multi-condition (adjustable speed and pitch angle) and multi-configuration (some components can be replaced) ducted fan tests, making it flexible and convenient to use.

[0130] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components, characterized in that, It includes a duct static component (100), a rotating component (200), a power component (300), a support component (400), and a measuring component (500); The support assembly (400) includes a test platform (401), a duct base (402), and a test system base (403); the measurement assembly (500) includes a thrust torque sensor (501), a first box balance (502), and a second box balance (503); The test system base (403) is vertically positioned above the ground; the first box balance (502) is mounted on the top of the test system base (403); the test platform (401) is fixedly mounted on the top of the first box balance (502); the second box balance (503) is mounted inside the test platform (401); the duct static component (100) is fixedly mounted on the top of the second box balance (503) via the duct base (402); the rotating component (200) is supported and mounted on the top of the test platform (401), and one end of the rotating component (200) is connected to the power component (300) via the thrust torque sensor (501), and the rotating component (200) is driven to rotate by the power component (300).

2. The test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components according to claim 1, characterized in that, The duct static assembly (100) includes a duct (101), a fairing arm (102), and a nacelle (103); The duct base (402) is fixedly installed at the bottom of the duct (101), and the duct base (402) is fixed on the top of the second box balance (503); the nacelle (103) is horizontally arranged at the axial center of the duct (101), and a plurality of rectifier arms (102) are radially distributed on the duct (101). One end of the rectifier arm (102) is fixed to the inner wall of the duct (101), and the other end is fixed to the outer wall of the nacelle (103). Therefore, the nacelle (103) is suspended and fixed by the duct (101) and the rectifier arm (102).

3. The test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components according to claim 2, characterized in that, The rotating assembly (200) includes a rotating shaft (201), blades (202), and a hub (203); The rotating shaft (201) is horizontally positioned through the cavity of the nacelle (103) and the center of the duct (101). One end of the rotating shaft (201) is connected to the power assembly (300) via the thrust torque sensor (501), and the power assembly (300) drives the rotating shaft (201) to rotate. Inside the duct (101) and on one side of each of the rectifier arms (102), a plurality of blades (202) are radially distributed along the duct (101). One end of each blade (202) has a gap with the inner wall of the duct (101), and the other end of each blade (202) is fixed to the rotating shaft (201) via the hub (203). When the rotating shaft (201) rotates, the hub (203) drives the blades (202) to rotate synchronously.

4. The test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components according to claim 3, characterized in that, The blade (202) is an adjustable blade with a pitch angle.

5. The test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components according to claim 4, characterized in that, The propeller hub (203) includes a front block (2031), a rear block (2032), a fastening bolt (2033), and a fixing nut (2034); The rotating shaft (201) is machined into a stepped shaft at the position where the propeller hub (203) is installed, and an external thread is machined on one side of the stepped shaft; The front hub block (2031) and the rear hub block (2032) are sequentially fitted onto the outside of the stepped shaft. Multiple grooves are formed circumferentially on opposite sides of the front hub block (2031) and the rear hub block (2032). The grooves of the front hub block (2031) and the rear hub block (2032) align to form a stepped cylindrical groove that matches the root of the blade (202). After the root of the blade (202) is embedded in the stepped cylindrical groove, it is secured by the hub fastening bolts (203... 3) Secure the front hub block (2031) and the rear hub block (2032) to achieve the fixation between the blade (202) and the hub (203); on the rear side of the rear hub block (2032), screw the hub fixing nut (2034) along the external thread of the stepped shaft to secure the front hub block (2031) and the rear hub block (2032) against the shoulder of the stepped shaft, thereby achieving the fixation between the hub (203) and the shaft (201).

6. The test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components according to claim 3, characterized in that, The rotating assembly (200) also includes a propeller cap (204) and a propeller cap fixing screw (205); The propeller cap (204) is fitted over the outside of the rotating shaft (201). One end of the rotating shaft (201) is fixed to the propeller hub (203) by the propeller cap fixing screw (205). The propeller cap (204) and the nacelle (103) are located on both sides of the propeller hub (203). Both the propeller cap (204) and the nacelle (103) have a shape in which their diameter gradually decreases along the direction away from the center of the duct (101).

7. The test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components according to claim 3, characterized in that, The support assembly (400) further includes: a bearing support (404), a bearing-sensor support (405), and a motor support (406); the bearing support (404), the bearing-sensor support (405), and the motor support (406) are fixedly installed on the test platform (401). The rotating assembly (200) further includes: a first bearing (206), a second bearing (207), a first diaphragm coupling (208), and a second diaphragm coupling (209); The first bearing (206) is mounted on the end of the rotating shaft (201) away from the thrust torque sensor (501). The first bearing (206) is disposed on the bearing support (404) and is supported by the bearing support (404). After the second bearing (207) is installed on one end of the rotating shaft (201) near the thrust torque sensor (501), the end of the rotating shaft (201) is connected to one end of the thrust torque sensor (501) through the first diaphragm coupling (208); the other end of the thrust torque sensor (501) is connected to the output end of the power assembly (300) through the second diaphragm coupling (209). The second bearing (207) and the thrust torque sensor (501) are disposed on the bearing-sensor support (405), and the bearing-sensor support (405) supports the second bearing (207) and the thrust torque sensor (501). The power assembly (300) is disposed on the motor support (406), and the power assembly (300) is supported by the motor support (406).

8. The test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components according to claim 3, characterized in that, The power assembly (300) includes a drive motor (301) and a motor fairing (302) for reducing aerodynamic interference of the drive motor (301); The output shaft of the drive motor (301), the thrust torque sensor (501), and the rotating shaft (201) are coaxially arranged.

9. The test system for precise measurement of the aerodynamic forces of a ducted fan as a whole and its multiple components according to claim 1, characterized in that, The first box balance (502) and the second box balance (503) are arranged alternately in the vertical direction.

10. A test method for a test system for precise measurement of the aerodynamic forces of a ducted fan as described in any one of claims 1-9, characterized in that, Includes the following steps: Step S1: Determine the test conditions for this test, including: the pitch angle of the blade (202), the rotational speed of the power unit (300), and the incoming wind speed; Step S2: Conduct a ducted fan wind tunnel test according to the test conditions; and during the ducted fan wind tunnel test, the thrust torque sensor (501), the first box balance (502), and the second box balance (503) collect test data in real time. Step S3 involves analyzing the collected test data to determine the overall aerodynamic performance parameters and component aerodynamic performance parameters of the ducted fan in this test, specifically including: Step S3.1, establish the coordinate system of the second box balance (503) as follows: take the center of the second box balance (503) as the origin, take the vertical upward as the positive Y-axis, take the horizontal direction towards the power component (300) as the positive X-axis, and determine the Z-axis according to the right-hand rule, thereby establishing the coordinate system of the second box balance (503); The coordinate system of the first box balance (502) is established as follows: with the center of the first box balance (502) as the origin, the vertical upward direction as the positive Y-axis, the horizontal direction towards the power component (300) as the positive X-axis, and the Z-axis determined according to the right-hand rule, thereby establishing the coordinate system of the first box balance (502); Step S3.2, the second box balance (503) collects the force and torque along its three coordinate axes, which are: force F XA F YA F ZA Torque MF XA MF YA MF ZA ; The first box balance (502) collects the force and torque along its three coordinate axes, which are: force F XB F YB F ZB Torque MF XB MF YB MF ZB ; The thrust torque sensor (501) collects the axial thrust T0 and power P0; Step S3.3, the overall aerodynamic performance parameters include: total thrust T, shaft power P, efficiency η1 when the incoming air velocity is greater than 0, and force efficiency η2 when the incoming air velocity is 0, which are determined by the following formulas: P = P0 Where: V is the incoming air velocity; η2 is the force efficiency when the incoming air velocity is 0, specifically the ducted fan propulsion efficiency under static thrust. The aerodynamic performance parameters of the components include blade thrust, duct thrust, and fairing arm thrust; among which, blade thrust is equal to the axial thrust T0 collected by the thrust torque sensor (501); duct thrust and fairing arm thrust are equal to the force F collected by the second box balance (503). XA .

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