A device and method for measuring the aerodynamic performance of a subsonic wind tunnel ducted fan

Abstract

The application discloses a subsonic wind tunnel ducted fan aerodynamic performance measuring device and a measuring method, and belongs to the technical field of special wind tunnel test testing. The ducted fan nacelle comprises an inner side and an outer side, the inner side is provided with an inlet total static pressure rake and a fan rear end total temperature total pressure rake, the inlet total static pressure rake is arranged in front of a ducted fan rotor and a hub, a stator hub is provided with a stator rear end total temperature total pressure rake, the stator rear end total temperature total pressure rake is the same in structure with the fan rear end total temperature total pressure rake, and the stator rear end total temperature total pressure rake is arranged at a rear end of a stator blade. The application discloses a subsonic wind tunnel ducted fan aerodynamic performance measuring device and a measuring method, and belongs to the technical field of special wind tunnel test testing.

Description

Technical Field

[0001] This invention belongs to the field of special wind tunnel testing technology, specifically a device and method for measuring the aerodynamic performance of a subsonic wind tunnel ducted fan. Background Technology

[0002] A ducted fan is an engine power unit in which an open fan is surrounded by a duct. It is widely used in the field of aero-engines to provide power for aircraft. A ducted fan can enclose the lift-generating components within the duct, suppressing tip vortices and thus increasing lift. Ducted fans enable unmanned aerial vehicles (UAVs) to achieve vertical takeoff and landing and hovering capabilities. Furthermore, ducted fans generate greater thrust than isolated open fans of the same diameter with the same power consumption, resulting in higher aerodynamic efficiency and better safety. Therefore, researching the aerodynamic performance of efficient ducted fans has significant engineering application value.

[0003] However, due to the interaction between the duct and the fan blades, the airflow of the ducted fan is very complex. It is usually necessary to conduct wind tunnel tests on the aerodynamic characteristics of the ducted fan. The wind tunnel test is used to measure the aerodynamic characteristics of the ducted fan, including the aerodynamic efficiency of the fan rotor, fan pressure, temperature rise and flow characteristics, so as to optimize the ducted fan blade shape or number.

[0004] Currently, there are few technologies related to aerodynamic performance measurement devices for subsonic wind tunnel ducted fans. For example, CN115875294B mainly introduces a test layout method for the front fan outlet of a three-ducted fan, focusing on determining the axial position of the test section of the front fan outlet of the three-ducted fan and the composition scheme of the test probe; CN114270051B describes a special overall structure of a ducted fan; CN115014771B introduces a design method for a hybrid exhaust test device for a dual-ducted fan, focusing on the use of a new hybrid exhaust structure in the intermediate casing exhaust section, which can ensure the high flow rate of the fan core in single-duct mode and the performance test layout of the outer bypass airflow in dual-duct mode; CN105134409B introduces a fan aerodynamic design method for high bypass ratio turbofan engines, focusing on the aerodynamic design method of rotor blades for ultra-high load and ultra-low speed ducted fans, effectively reducing fan noise and weight while ensuring fan aerodynamic performance.

[0005] The aforementioned existing technologies only introduce the overall structure of ducted fans, the test layout method for the outlet of ducted fan experimental fans, and the aerodynamic design method of ducted fans, etc., without involving the aerodynamic performance measurement system of scaled-down ducted fan models in large subsonic wind tunnels. It is difficult to meet the measurement requirements of ducted fan rotor aerodynamic efficiency, fan pressure ratio and temperature rise ratio characteristics, fan intake flow characteristics, etc. in ducted fan engine design.

[0006] Therefore, this application proposes a device and method for measuring the aerodynamic performance of a subsonic wind tunnel ducted fan to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to address the current lack of aerodynamic performance measurement systems for scaled-down ducted fan models in large subsonic wind tunnels, which fails to meet the measurement needs in ducted fan engine design. A brief overview of the invention is provided below to offer a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0008] The technical solution of the present invention:

[0009] Option 1: A subsonic wind tunnel ducted fan aerodynamic performance measurement device, comprising a tail support rod, an air motor, an air motor mounting housing, a high-speed rotor shaft, a rotary balance, ducted fan rotor blades and a rotor hub and stator blades. The tail support rod is installed inside the subsonic wind tunnel via a wind tunnel angle-of-attack mechanism. The front end of the tail support rod is connected to one end of the air motor mounting housing, and the other end of the air motor mounting housing is connected to a central connecting seat. A high-pressure drive air pipeline is installed on the outside of the air motor mounting housing. One end of the high-pressure drive air pipeline is arranged outside the subsonic wind tunnel, and the other end is connected to the inside of the air motor mounting housing. The central connecting seat is installed inside the subsonic wind tunnel via a tension wire support. A bearing housing is connected to the central connecting seat. Multiple stator blades are evenly distributed around the circumference of the bearing housing. The lower end of each stator blade is connected to the bearing housing via a stator hub, and the upper end is connected to the ducted fan nacelle.

[0010] The air motor is installed in the air motor housing. The rear end of the air motor rotor output shaft is connected to the high-speed electric slip ring. The front end of the rotor output shaft is connected to the rear end of the high-speed rotor shaft through a coupling. The high-speed rotor shaft is rotatably installed in the bearing housing. The front end of the high-speed rotor shaft is connected to the rotary balance. The measuring end of the rotary balance is connected to the ducted fan rotor blades and hub. The front end of the ducted fan rotor blades and hub is connected to the blade cap support. The blade cap is fixed to the ducted fan rotor blades and hub through the blade cap support.

[0011] The ducted fan nacelle includes an inner side and an outer side. The ducted fan nacelle has a hollow structure. An inlet total static pressure rake and a fan rear end total temperature and pressure rake are installed on the inner side of the ducted fan nacelle. The fan rear end total temperature and pressure rake is arranged between the ducted fan rotor blades and the hub and stator blades. The inlet total static pressure rake is arranged at the front end of the ducted fan rotor blades and the hub.

[0012] The stator hub is equipped with a stator rear end total temperature and pressure rake, which has the same structure as the fan rear end total temperature and pressure rake. The stator rear end total temperature and pressure rake is arranged at the rear end of the stator blade.

[0013] Furthermore, the high-speed electric slip ring includes a slip ring rotor and a slip ring stator. The slip ring rotor and slip ring stator are installed inside the high-speed electric slip ring housing. The slip ring rotor is connected to the rear end of the rotor output shaft of the air motor. The slip ring rotor is rotatably mounted inside the slip ring stator via bearings. The slip ring rotor is connected to the rotor signal line, and the slip ring stator is connected to the stator signal line. The stator signal line is arranged inside the stator signal line sealing housing. The front end of the stator signal line sealing housing is connected to the high-speed electric slip ring housing, and the rear end of the stator signal line sealing housing is sealed by a sealing screw. A stator signal line conductor sealing tube is connected to the stator signal line sealing housing, and the stator signal line conductor sealing tube communicates with the stator signal line sealing housing for placing the stator signal line.

[0014] Furthermore, the high-speed slip ring housing is connected to an oil inlet pipe and an oil outlet pipe. The other ends of the oil inlet pipe and the oil outlet pipe are installed on the oil pipeline fixing seat. The lubricating oil enters the space between the slip ring rotor and the slip ring stator through the oil inlet pipe and is led out through the oil outlet pipe.

[0015] Furthermore, the lubricating oil pipeline fixing seat is connected to one end of the air pressure balancing steel pipe, the other end of the air pressure balancing steel pipe is connected to the inner cavity of the tail support rod, the lubricating oil pipeline fixing seat is connected to one end of the air pressure balancing hose, the other end of the air pressure balancing hose is connected to the outer shell of the high-speed electric slip ring, and the inner cavities of the air pressure balancing steel pipe, the lubricating oil pipeline fixing seat, the air pressure balancing hose, and the outer shell of the high-speed electric slip ring are connected in sequence.

[0016] Furthermore, the rotating balance has a spoke-type structure. The fixed end of the rotating balance is connected to the high-speed rotor shaft via a spline. The measuring end of the rotating balance is connected to the ducted fan rotor blades and hub via a flange. The measuring beams of the rotating balance are in two rows, each row having eight axially uniform measuring beams. There are eight axially distributed support ribs between the two rows of measuring beams. The signal amplifier is installed in the hollow structure of the high-speed rotor shaft and is arranged near the rotating balance.

[0017] Furthermore, the high-speed rotor shaft is mounted in a bearing housing via a front bearing and a rear bearing, both of which are dual-bearing structures.

[0018] Furthermore, a propeller cap bottom resistance measuring plate is installed on the stator hub, and the propeller cap bottom resistance measuring plate is arranged at the rear end of the ducted fan rotor blades and the propeller hub.

[0019] Furthermore, a nozzle is installed on the bearing housing. The nozzle has a split structure and is fixed to the outer surface of the bearing housing by pins.

[0020] Option 2: A method for measuring the aerodynamic performance of a subsonic wind tunnel ducted fan, which is based on the aerodynamic performance measuring device for a subsonic wind tunnel ducted fan described in Option 1, and includes the following steps:

[0021] Step 1: High-pressure gas is introduced into the fixed housing of the air motor through the high-pressure drive air pipeline, which drives the air motor to rotate. The rotation of the air motor, through the coupling, drives the high-speed rotor shaft, ducted fan rotor blades and hub to rotate to the target speed.

[0022] Step 2: Start the subsonic wind tunnel to bring the outflow Mach number to the target simulated value;

[0023] Step 3: Measure the total pressure and static pressure of the airflow at the front end of the ducted fan using the inlet total static pressure rake, and calculate the average airflow velocity and average flow rate based on the corresponding cross-sectional area;

[0024] Step 4: Measure the total temperature and total pressure between the rotor blades and the hub and stator blades of the ducted fan using the total temperature and total pressure rake at the rear end of the fan, and measure the total temperature and total pressure at the rear end of the stator blades using the total temperature and total pressure rake at the rear end of the stator to obtain the pressurization and heating characteristics of the rotor blades and stator blades.

[0025] Step 5: Measure the tension and torque of the ducted fan using a rotary balance, amplify and filter the output signal of the rotary balance using a signal amplifier, and calculate the power and efficiency of the ducted fan by combining the rotational speed.

[0026] Step Six: Obtain static pressure data through the static pressure measuring point on the bottom resistance measuring plate of the propeller cap, correct the tension measured by the rotating balance, and complete the comprehensive measurement of the aerodynamic performance of the ducted fan.

[0027] The present invention has the following beneficial effects:

[0028] 1. The subsonic wind tunnel ducted fan aerodynamic performance measurement device of the present invention adopts a large subsonic wind tunnel and an air motor to drive the ducted fan to rotate at a certain speed. It can realize the similarity simulation of the main similarity parameters, geometric parameters, outflow Mach number, and advance ratio of the fan in the wind tunnel. The inlet total static pressure rake is designed at the rotor blades and hub of the ducted fan. The average velocity and average flow rate of the ducted fan airflow are calculated by the pressure of the inlet total static pressure rake and the total temperature and pressure rake at the rear end of the fan. The total temperature and pressure rakes at the rear end of the fan and the stator are designed with equal area distribution between the rotor blades and hub of the ducted fan and the stator blades, and at the rear end of the stator blades. The total pressure and total temperature change characteristics of the rotor blades and the stator can be measured.

[0029] 2. The rotating balance of the subsonic wind tunnel ducted fan aerodynamic performance measuring device of the present invention adopts a spoke-type rotating balance. The spoke-type rotating balance measures the tension and torque of the ducted fan, and can realize the measurement of the tension, torque, power and efficiency of the ducted fan under different Mach numbers and different speeds.

[0030] 3. The subsonic wind tunnel ducted fan aerodynamic performance measuring device of the present invention utilizes a tensioned wire support to firmly fix the central connecting seat to the wall of the subsonic wind tunnel, which significantly improves the rigidity of the entire measuring device and avoids the problem of resonance of the ducted fan aerodynamic performance measuring device in the subsonic wind tunnel.

[0031] 4. The subsonic wind tunnel duct fan aerodynamic performance measuring device of the present invention has an oil-lubricated high-speed slip ring connected to the tail end of the air motor. By providing lubricating oil at a constant temperature, the signal transmission error of the high-speed slip ring caused by the cooling of the air motor outlet is avoided. A signal amplifier that rotates with the rotating balance is designed inside the propeller cap to amplify the signal of the rotating balance, effectively avoiding the problem of signal transmission interference and significantly improving the measurement accuracy of the aerodynamic performance measuring device. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of a subsonic wind tunnel duct fan aerodynamic performance measurement device;

[0033] Figure 2 This is a cross-sectional structural schematic diagram of a subsonic wind tunnel duct fan aerodynamic performance measurement device;

[0034] Figure 3 This is a schematic diagram of the structure of a rotating balance;

[0035] Figure 4 This is a schematic diagram of a high-speed slip ring.

[0036] Figure 5 This is a schematic diagram of the cross-sectional structure of a high-speed electric slip ring;

[0037] Figure 6 yes Figure 2 A partial schematic diagram.

[0038] In the diagram: 1-Subsonic wind tunnel, 2-Wind tunnel variable angle of attack mechanism, 3-Tail support rod, 4-High-pressure drive air pipeline, 5-Air motor, 6-Air motor mounting housing, 7-High-speed electric slip ring, 8-Center connecting seat, 9-Wire support, 10-Coupling, 11-High-speed rotor shaft, 12-Front bearing, 13-Rear bearing, 14-Bearing housing, 15-Rotating balance, 16-Signal amplifier, 17-Ducted fan rotor blades and hub, 18-Duct cap bottom resistance measuring plate, 19-Duct cap support, 20-Duct cap, 21-Stator blade, 22-Stator hub, 23-Nozzle, 24-Ducted fan rotor blade 25 - Inside of the duct fan nacelle; 26 - Outside of the duct fan nacelle; 27 - Inlet total static pressure rake; 28 - Rear end total temperature and pressure rake of the fan; 79 - Rear end total temperature and pressure rake of the stator; 70 - Slip ring rotor; 71 - Slip ring stator; 72 - Rotor signal line; 73 - Stator signal line; 74 - Bearing; 75 - Stator signal line sealing housing; 76 - Sealing screw; 77 - Stator signal line conductor sealing tube; 78 - Air pressure balancing steel pipe; 79 - Air pressure balancing hose; 70 - Lubricating oil pipeline fixing seat; 710 - Lubricating oil inlet pipe; 711 - Lubricating oil outlet pipe; 712 - High-speed electric slip ring housing. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0040] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections (i.e., non-detachable connections) include, but are not limited to, conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include, but are not limited to, conventional disassembly methods such as threaded connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can always be found to achieve the function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a hinged connection can be chosen for detachable connections.

[0041] Example 1, combined with Figures 1-3 , Figure 6This embodiment describes a subsonic wind tunnel ducted fan aerodynamic performance measurement device, comprising a tail support rod 3, an air motor 5, an air motor mounting housing 6, a high-speed rotor shaft 11, a rotating balance 15, ducted fan rotor blades and a hub 17 and stator blades 21. The tail support rod 3 is mounted inside a subsonic wind tunnel 1 via a wind tunnel angle-of-attack mechanism 2. The front end of the tail support rod 3 is connected to one end of the air motor mounting housing 6, and the other end of the air motor mounting housing 6 is connected to a central connecting seat 8. A high-pressure drive air pipe 4 is installed on the outside of the air motor mounting housing 6. One end of the high-pressure drive air pipe 4 is arranged on the outside of the subsonic wind tunnel 1, and the other end is connected to the inside of the air motor mounting housing 6. The middle connecting seat 8 is installed in the subsonic wind tunnel 1 through the tension wire support 9. The bearing seat 14 is connected to the middle connecting seat 8. Multiple stator blades 21 are evenly distributed on the circumference of the bearing seat 14. The lower end of each stator blade 21 is connected to the bearing seat 14 through the stator hub 22, and the upper end is connected to the ducted fan nacelle.

[0042] Air motor 5 is installed in air motor housing 6. The rear end of the rotor output shaft of air motor 5 is connected to high-speed electric slip ring 7. The front end of the rotor output shaft is connected to the rear end of high-speed rotor shaft 11 through coupling 10. High-speed rotor shaft 11 is rotatably installed in bearing seat 14. The front end of high-speed rotor shaft 11 is connected to rotary balance 15. The measuring end of rotary balance 15 is connected to ducted fan rotor blades and hub 17. The front end of ducted fan rotor blades and hub 17 is connected to blade cap support 19. Blade cap 20 is fixed to ducted fan rotor blades and hub 17 through blade cap support 19.

[0043] The ducted fan nacelle includes an inner nacelle 24 and an outer nacelle 25. The ducted fan nacelle has a hollow structure. An inlet total static pressure rake 26 and a fan rear end total temperature and pressure rake 27 are installed on the inner nacelle 24. The fan rear end total temperature and pressure rake 27 is arranged between the ducted fan rotor blades and hub 17 and the stator blades 21. The inlet total static pressure rake 26 is arranged at the front end of the ducted fan rotor blades and hub 17.

[0044] The stator hub 22 is equipped with a stator rear end total temperature and pressure rake 28, which has the same structure as the fan rear end total temperature and pressure rake 27. The stator rear end total temperature and pressure rake 28 is arranged at the rear end of the stator blade 21.

[0045] The test was conducted in a subsonic wind tunnel 1 with a test section size greater than 2.4m. The subsonic wind tunnel 1 was either a continuous wind tunnel or a transient wind tunnel. The wind tunnel variable angle of attack mechanism 2, used to connect the tail support rod 3, adopted a curved structure. The wind tunnel variable angle of attack mechanism 2 was required to have an angle of attack variation capability of ±8°, and the angle of attack control accuracy was required to be better than 3′. The front end of the tail support rod 3 was connected to the air motor fixing housing 6, and the rear end was connected to the wind tunnel variable angle of attack mechanism 2. Both connections were flanged and fastened with bolts. The internal structure was hollow and designed with a stop. The outer diameter of the tail support rod 3 was 280mm, the inner diameter of the hollow structure was 140mm, and the length was approximately 830mm. The material was high-strength precipitation hardening stainless steel 05Cr17Ni4Cu4Nb. Cable trays were designed on both sides of the tail support rod 3 to allow external pipelines to be introduced into the variable angle of attack mechanism 2.

[0046] The high-pressure driven air line 4 has an inner diameter of 60mm, a wall thickness of 8mm, a design pressure greater than 8.0MPa, and requires the high-pressure air temperature inside the high-pressure driven air line 4 to be greater than 70℃, the filtration accuracy to be less than 20μm, the dew point to be less than -40℃, and the airflow velocity to be less than 68m / s.

[0047] The front end of the air motor mounting housing 6 is connected to the middle connecting seat 8 via a flange, and a stop is designed. It is secured with bolts and has a hollow internal structure. The high-pressure drive air pipeline 4 drives the air motor 5. An exhaust port is designed at the rear of the air motor mounting housing 6 to allow the air from the turbine driven by the air motor 5 to be discharged. Cable trays are designed on both sides. The air motor mounting housing 6 has an outer diameter of 280mm, an inner diameter of 200mm for the hollow structure, and a length of approximately 910mm. It is made of high-strength precipitation-hardening stainless steel 05Cr17Ni4Cu4Nb.

[0048] The air motor 5 is the power unit of the subsonic wind tunnel ducted fan aerodynamic performance measurement device. Its working principle is that high-pressure gas drives the 6-stage turbine inside the air motor 5, and the rotation of the turbine drives the output shaft to rotate. The air motor 5 has a rated power of 475kW, a rated speed of 7000 rpm, a maximum speed of 9200 rpm, an outer diameter of 200mm, and a length of approximately 590mm. It adopts a 6-stage turbine structure. The rotor output shaft is located at the center of the air motor 5. The front end of the rotor output shaft is used to connect to the rotating parts, and the rear end is used to connect to the high-speed electric slip ring 7. The diameter of the rotor output shaft is 45mm.

[0049] The tension line support 9 consists of two support ribs, an upper support rib and a lower support rib. Both support ribs are connected at one end to the central connecting seat 8 via a flange, and at the other end to the wall of the subsonic wind tunnel 1 via a flange. The two support ribs of the tension line support 9 have identical structures, with a length of approximately 1060 mm, a length in the airflow direction of approximately 40 mm, a maximum thickness of 20 mm, and are made of 30CrMnSi material. If the aerodynamic performance measurement device for the subsonic wind tunnel ducted fan requires a change in angle of attack, then a tension line support 9 of a suitable size needs to be replaced.

[0050] The middle connecting seat 8 is a hollow structure. The front section is fastened to the bearing seat 14 through a flange. Three interfaces are reserved on the outside and connected to the tension line support 9 as three support ribs. The middle connecting seat 8 has an outer diameter of 274mm, an inner diameter of 224mm, and a length of about 204mm. The material is 30CrMnSi. A rectifier plate with a wall thickness of 3mm is designed on the outside to achieve rectification on the outer surface of the middle connecting seat 8.

[0051] The rotor output shaft of the air motor 5 is connected to the coupling 10 via a coupling tensioning sleeve. The other end of the coupling 10 is connected to the high-speed rotor shaft 11 via a spline. The spline has a module of 1mm, a pressure angle of 30°, 53 spline teeth, a pitch circle diameter of 53.0mm, a major diameter of 54.0mm, a working height of 1.0mm for the key teeth, and a key length of 18mm. The coupling 10 transmits only torque and not axial force. A high-speed diaphragm coupling with a diaphragm material of 65Mn is usually selected. The coupling 10 can compensate for the radial deviation of the high-speed rotor shaft 11 and the central shaft of the air motor 5 to be less than 0.3mm and the angular deviation to be less than 1.0°. The other end of the high-speed rotor shaft 11 is connected to the rotary balance 15 via a spline. The spline has a module of 1 mm, a pressure angle of 30°, 82 spline teeth, a pitch circle diameter of 82.0 mm, a major diameter of 83.0 mm, a working height of 1.0 mm, and a length of 14 mm. The high-speed rotor shaft 11 is approximately 770 mm long, has a maximum outer diameter of 120 mm, and is typically made of 0Cr17Ni4Cu4Nb material.

[0052] The high-speed rotor shaft 11 is supported in the bearing housing 14 by a front bearing 12 and a rear bearing 13. Both the front bearing 12 and the rear bearing 13 are dual bearing structures, grease lubricated, and have a limiting speed of 12,000 rpm. The front bearing 12 is a face-to-face paired angular contact ball bearing, which is only subjected to radial force, with an inner diameter of 100 mm and an outer diameter of 150 mm. The rear bearing 13 is a back-to-back paired angular contact ball bearing, which is subjected to both radial and axial forces, with an inner diameter of 85 mm and an outer diameter of 130 mm.

[0053] The rotating balance 15 has a spoke-type structure. The measuring end of the rotating balance 15 is connected to the ducted fan rotor blades and hub 17 via a flange, secured with M8 screws and locating pins. The rotating balance 15 has two rows of measuring beams, each row containing eight axially evenly distributed measuring beams. Eight axially evenly distributed support ribs are designed between the two rows of measuring beams. The central axis of the rotating balance 15 is the X-axis. The X-axis is horizontal, pointing towards the fixed end of the rotating balance 15, which is positive. The Y-axis is vertically upward, which is also positive. The Z-axis conforms to the right-hand rule. The positive X-axis of the rotating balance 15 has a negative tensile force, the positive Y-axis has a positive lift force, and the positive Z-axis has a positive lateral force. The outer diameter of the rotating balance 15 is 232 mm, the length is 80 mm, and the material is typically 0Cr17Ni4Cu4Nb.

[0054] The signal amplifier 16 is a signal conditioning device with amplification and filtering functions. Its main purpose is to amplify the strain gauge voltage output on the rotating balance 15 and reduce the interference from the noise of the air motor 5 and the high-speed rotation of the high-speed slip ring 7 when the strain gauge voltage output is affected. The signal amplifier 16 has a cylindrical structure, 8 channels, a signal amplification factor of 250 times, and a maximum speed of not less than 9000 rpm. Installing it near the rotating balance 15 helps to ensure the accuracy of the signal.

[0055] The ducted fan rotor blades and hub 17 are integrated as a single unit. The inner side is connected to the floating end of the rotating balance 15 via a flange, and the front end is also connected to the propeller cap support via a flange, both secured with pins. The ducted fan rotor blades and hub 17 consist of 16 blades, with a maximum outer diameter of approximately 640 mm, evenly distributed circumferentially, and made of titanium alloy. The propeller cap bottom resistance measuring plate 18 is located at the rear end of the ducted fan rotor blades and hub 17, with a gap of approximately 2.5 mm between it and the ducted fan rotor blades and hub 17. It is connected to the stator hub 22 via a flange. The propeller cap bottom resistance measuring plate 18 requires different numbers of area-averaged hydrostatic measuring points to be designed according to actual needs. It is mainly used for tension correction of the ducted fan rotor blades and hub 17. The propeller cap bottom resistance measuring plate 18 has an inner diameter of 86 mm, an outer diameter of 296 mm, a wall thickness of 5 mm, and an inner diameter of approximately 1.0 mm for the hydrostatic measuring point holes. It is made of aluminum alloy 2A70. The propeller cap 20 is fixed to the ducted fan rotor blades and the propeller hub 17 by the propeller cap support 19. The propeller cap support 19 is made of 30CrMnSi material, and the propeller cap 20 is made of aluminum alloy 2A70.

[0056] The lower end of the stator blade 21 is connected to the stator hub 22 via a flange and a stop, and the upper end is fastened to the inner side 24 of the ducted fan nacelle via a flange. There are a total of 26 stator blades 21, of which 4 are thickened hollow structures used for arranging pipelines, etc. The maximum outer diameter is about 640mm, and they are evenly distributed circumferentially. The material is titanium alloy. The stator hub 22 is fastened to the bearing seat 14 via a flange. At the same time, a dovetail groove structure is designed on the outer surface to connect with the stator blade 21. The material is 30CrMnSi.

[0057] The nozzle 23 adopts a convenient half-and-half structure and is fixed to the outer surface of the bearing seat 14 by pins. The material is aluminum alloy 2A70. The inner side 24 and the outer side 25 of the ducted fan nacelle form the ducted fan nacelle. The interior of the nacelle is a hollow structure. The inlet total static pressure rake 26 and the fan rear end total temperature and total pressure rake 27 are installed inside the hollow structure. The material is aluminum alloy 2A70. The inlet total static pressure rake 26 is divided into four rake bodies with the same structure. The four rake bodies are evenly distributed around the circumference. Each rake body has several total pressure rakes and static pressure rakes. The air mass flow rate of this section can be measured by the total static pressure relationship and the corresponding area.

[0058] The total temperature and pressure rake 27 at the rear end of the fan and the total temperature and pressure rake 28 at the rear end of the stator have the same structure. Both are 8-point total temperature and pressure composite rakes with equal area distribution. The total temperature and pressure rake 27 at the rear end of the fan is located between the ducted fan rotor blades and hub 17 and the stator blades 21, while the total temperature and pressure rake 28 at the rear end of the stator blades 21 is located at the rear end of the stator blades 21. The pressure and temperature increase characteristics of the rotor blades and the stator can be measured through the total temperature and pressure rake 27 at the rear end of the fan and the total temperature and pressure rake 28 at the rear end of the stator.

[0059] The high-speed rotor shaft 11, coupling 10, and air motor 5 all have hollow internal structures. These hollow structures are used to house the power and test lines connecting the signal amplifier 16 and the high-speed slip ring 7. The diameter of the hollow structure is kept as small as possible while ensuring sufficient wiring space. The outer walls of the bearing housing 14, the central connecting seat 8, the air motor mounting housing 6, and the dedicated tail support rod 3 must all be designed with appropriate wiring channels for arranging cables and pressure testing lines. These channels should be kept as small as possible while ensuring sufficient wiring space. Wiring covers should be designed on the outside of the wiring channels, and the internal sealing of the wiring channels should be considered to avoid or reduce airflow within them.

[0060] Example 2, combined with Figures 1-6 This embodiment describes a subsonic wind tunnel duct fan aerodynamic performance measuring device. The high-speed electric slip ring 7 includes a slip ring rotor 71 and a slip ring stator 72. The slip ring rotor 71 and slip ring stator 72 are installed inside a high-speed electric slip ring housing 714. The slip ring rotor 71 is connected to the rear end of the rotor output shaft of the air motor 5. The slip ring rotor 71 is rotatably disposed inside the slip ring stator 72 via a bearing 75. The slip ring rotor 71 is connected to a rotor signal line 73, and the slip ring stator 72 is connected to a stator signal line 74. The stator signal line 74 is arranged inside a stator signal line sealing housing 76. The front end of the stator signal line sealing housing 76 is connected to the high-speed electric slip ring housing 714, and the rear end of the stator signal line sealing housing 76 is sealed by a sealing screw 77. A stator signal line conductor sealing tube 78 is connected to the stator signal line sealing housing 76 and communicates with the stator signal line sealing housing 76 for placing the stator signal line 74.

[0061] The high-speed slip ring housing 714 is connected to an oil inlet pipe 712 and an oil outlet pipe 713. The other ends of the oil inlet pipe 712 and the oil outlet pipe 713 are installed on the oil pipeline fixing seat 711. The lubricating oil enters the space between the slip ring rotor 71 and the slip ring stator 72 through the oil inlet pipe 712 and is led out through the oil outlet pipe 713.

[0062] The lubricating oil pipeline fixing seat 711 is connected to one end of the air pressure balancing steel pipe 79, and the other end of the air pressure balancing steel pipe 79 is connected to the inner cavity of the tail support rod 3. The lubricating oil pipeline fixing seat 711 is connected to one end of the air pressure balancing hose 710, and the other end of the air pressure balancing hose 710 is connected to the high-speed electric slip ring housing 714. The air pressure balancing steel pipe 79, the lubricating oil pipeline fixing seat 711, the air pressure balancing hose 710 and the inner cavity of the high-speed electric slip ring housing 714 are connected in sequence.

[0063] The high-speed electric slip ring 7 transmits signals through the high-speed relative rotation of the slip ring rotor 71 and the slip ring stator 72. The high-speed electric slip ring 7 provides room temperature lubricating oil, which enters the space between the slip ring rotor 71 and the slip ring stator 72 through the lubricating oil inlet pipe 712. The room temperature lubricating oil is led out through the lubricating oil outlet pipe 713. By providing lubricating oil at a constant temperature, the signal transmission error of the high-speed electric slip ring is avoided due to the temperature drop at the outlet of the air motor. The total lubricating oil pressure is about 0.8 MPa, and the inside of the high-speed electric slip ring 7 is sealed.

[0064] Example 3, combined with Figures 1-6 This embodiment describes a method for measuring the aerodynamic performance of a subsonic wind tunnel ducted fan, which includes the following steps:

[0065] Step 1: Turn on the high-pressure gas supply system and introduce high-pressure gas into the air motor housing 6 through the regulating valve to drive the air motor 5 to rotate. Adjust the gas pressure to make the ducted fan with a diameter of 0.64m reach a speed of 7300r / min and stabilize for 5 minutes. Then, drive the high-speed rotor shaft 11, ducted fan rotor blades and hub 17 to rotate to the target speed through the coupling 10.

[0066] Step 2: Start the subsonic wind tunnel 1, adjust the wind tunnel medium pressure and vacuum system to make the total pressure of the wind tunnel reach 50000Pa, adjust the wind tunnel heat exchanger to make the total temperature of the wind tunnel reach 295K, and simultaneously adjust the wind tunnel fan speed to make the Mach number of the wind tunnel outflow reach 0.49. After the flow field stabilizes, record the wind tunnel operating parameters.

[0067] Step 3: Measure the total pressure and static pressure of the airflow at the front end of the ducted fan using the inlet total static pressure rake 26. Collect the data continuously for 30 seconds, take the average value, and calculate that the average airflow velocity is 164.81 m / s and the average flow rate is 21.64 kg / s.

[0068] Step 4: Measure the total temperature and total pressure data between the ducted fan rotor blades and the hub 17 and stator blades 21 using the total temperature and total pressure rake 27 at the rear end of the fan. Calculate that the total pressure ratio at the rear end of the rotor is 1.32, with a total temperature increase of 15.5K, and the total pressure ratio at the rear end of the stator is 1.31, with a total temperature increase of 15.5K.

[0069] Step 5: Collect the tension and torque data of the rotating balance 15. After amplification and filtering by the signal amplifier 16, the average tension is 839.67N and the average torque is 258.74N·m.

[0070] Step Six: Collect the static pressure data of the propeller cap bottom resistance measuring plate 18, calculate the propeller cap bottom resistance as -73.16N, and calculate the centrifugal force correction of the rotating balance as 70.83N based on the rotational speed. The two correct the tension measured by the rotating balance as 839.67N to 837.34N. Finally, calculate the ducted fan tension coefficient as 0.633, and calculate the ducted fan power as 198349.2W, the power factor as 1.919, and the ducted fan efficiency as 69.2%.

[0071] This embodiment is merely an exemplary illustration of the present invention and does not limit its scope of protection. Those skilled in the art can make partial changes to it, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A device for measuring the aerodynamic performance of a subsonic wind tunnel ducted fan, characterized in that: The components include a tail strut (3), an air motor (5), an air motor mounting housing (6), a high-speed rotor shaft (11), a rotating balance (15), ducted fan rotor blades and hub (17), and stator blades (21). The tail end of the tail strut (3) is installed in a subsonic wind tunnel (1) via a wind tunnel angle-of-attack mechanism (2). The front end of the tail strut (3) is connected to one end of the air motor mounting housing (6), and the other end of the air motor mounting housing (6) is connected to the central connecting seat (8). A high-speed rotor shaft (11), a rotating balance (15), a ducted fan rotor blade and hub (17), and a stator blade (21) are installed on the outside of the air motor mounting housing (6). High-pressure driven air pipeline (4), one end of which is arranged outside the subsonic wind tunnel (1), and the other end is connected to the inside of the air motor fixed housing (6). The middle connecting seat (8) is installed inside the subsonic wind tunnel (1) through the tension wire support (9). The bearing seat (14) is connected to the middle connecting seat (8). Multiple stator blades (21) are evenly distributed on the circumference of the bearing seat (14). The lower end of each stator blade (21) is connected to the bearing seat (14) through the stator hub (22), and the upper end is connected to the ducted fan nacelle. An air motor (5) is installed inside an air motor housing (6). The rear end of the rotor output shaft of the air motor (5) is connected to a high-speed electric slip ring (7). The front end of the rotor output shaft is connected to the rear end of a high-speed rotor shaft (11) via a coupling (10). The high-speed rotor shaft (11) is rotatably installed in a bearing seat (14). The front end of the high-speed rotor shaft (11) is connected to a rotating balance (15). The measuring end of the rotating balance (15) is connected to the ducted fan rotor blades and hub (17). The front end of the ducted fan rotor blades and hub (17) is connected to a propeller cap support (19). The propeller cap (20) is fixed to the ducted fan rotor blades and hub (17) via the propeller cap support (19). The ducted fan nacelle includes an inner side (24) and an outer side (25) of the ducted fan nacelle. The ducted fan nacelle has a hollow structure. An inlet total static pressure rake (26) and a fan rear end total temperature and pressure rake (27) are installed on the inner side (24) of the ducted fan nacelle. The fan rear end total temperature and pressure rake (27) is arranged between the ducted fan rotor blades and hub (17) and the stator blades (21). The inlet total static pressure rake (26) is arranged at the front end of the ducted fan rotor blades and hub (17). The stator hub (22) is equipped with a stator rear end total temperature and pressure rake (28). The stator rear end total temperature and pressure rake (28) has the same structure as the fan rear end total temperature and pressure rake (27). The stator rear end total temperature and pressure rake (28) is arranged at the rear end of the stator blade (21).

2. The aerodynamic performance measuring device for a subsonic wind tunnel duct fan according to claim 1, characterized in that: The high-speed electric slip ring (7) includes a slip ring rotor (71) and a slip ring stator (72). The slip ring rotor (71) and slip ring stator (72) are installed inside the high-speed electric slip ring housing (714). The slip ring rotor (71) is connected to the rear end of the rotor output shaft of the air motor (5). The slip ring rotor (71) is rotatably mounted inside the slip ring stator (72) through a bearing (75). The slip ring rotor (71) is connected to the rotor signal line (73), and the slip ring stator (72) is connected to the stator signal line (74). The stator signal line (74) is arranged inside the stator signal line sealing housing (76). The front end of the stator signal line sealing housing (76) is connected to the high-speed slip ring housing (714). The rear end of the stator signal line sealing housing (76) is sealed by a sealing screw (77). A stator signal line conductor sealing tube (78) is connected to the stator signal line sealing housing (76). The stator signal line conductor sealing tube (78) is connected to the stator signal line sealing housing (76) and is used to place the stator signal line (74).

3. The aerodynamic performance measuring device for a subsonic wind tunnel duct fan according to claim 2, characterized in that: The high-speed electric slip ring housing (714) is connected to an oil inlet pipe (712) and an oil outlet pipe (713). The other ends of the oil inlet pipe (712) and the oil outlet pipe (713) are installed on the oil pipeline fixing seat (711). The lubricating oil enters the space between the slip ring rotor (71) and the slip ring stator (72) through the oil inlet pipe (712) and is led out through the oil outlet pipe (713).

4. The aerodynamic performance measuring device for a subsonic wind tunnel duct fan according to claim 3, characterized in that: The lubricating oil pipeline fixing seat (711) is connected to one end of the air pressure balancing steel pipe (79), and the other end of the air pressure balancing steel pipe (79) is connected to the inner cavity of the tail support rod (3). The lubricating oil pipeline fixing seat (711) is connected to one end of the air pressure balancing hose (710), and the other end of the air pressure balancing hose (710) is connected to the high-speed electric slip ring housing (714). The inner cavities of the air pressure balancing steel pipe (79), the lubricating oil pipeline fixing seat (711), the air pressure balancing hose (710), and the high-speed electric slip ring housing (714) are connected in sequence.

5. A subsonic wind tunnel duct fan aerodynamic performance measuring device according to claim 1 or 4, characterized in that: The rotating balance (15) has a spoke structure. The fixed end of the rotating balance (15) is connected to the high-speed rotor shaft (11) via a spline. The measuring end of the rotating balance (15) is connected to the ducted fan rotor blades and hub (17) via a flange. The measuring beam of the rotating balance (15) is in two rows, with eight axially uniform measuring beams in each row. There are eight axially distributed support ribs between the two rows of measuring beams. The signal amplifier (16) is installed in the hollow structure of the high-speed rotor shaft (11) and is arranged near the rotating balance (15).

6. The aerodynamic performance measuring device for a subsonic wind tunnel duct fan according to claim 5, characterized in that: The high-speed rotor shaft (11) is installed in the bearing housing (14) through the front bearing (12) and the rear bearing (13), both of which are double bearing structures.

7. The aerodynamic performance measuring device for a subsonic wind tunnel duct fan according to claim 6, characterized in that: The stator hub (22) is equipped with a propeller cap bottom resistance measuring plate (18), which is arranged at the rear end of the ducted fan rotor blades and the propeller hub (17).

8. The aerodynamic performance measuring device for a subsonic wind tunnel duct fan according to claim 7, characterized in that: The bearing housing (14) is equipped with a nozzle (23), which has a split structure and is fixed to the outer surface of the bearing housing (14) by a pin.

9. A method for measuring the aerodynamic performance of a subsonic wind tunnel ducted fan, the method being implemented using the aerodynamic performance measuring device for a subsonic wind tunnel ducted fan as described in claim 8, characterized in that... Includes the following steps: Step 1: High-pressure gas is introduced into the fixed housing (6) of the air motor through the high-pressure drive air pipe (4) to drive the air motor (5) to rotate, and through the coupling (10) drive the high-speed rotor shaft (11) and the ducted fan rotor blades and hub (17) to rotate to the target speed. Step 2: Start the subsonic wind tunnel (1) to make the outflow Mach number reach the target simulated value; Step 3: Measure the total pressure and static pressure of the airflow at the front end of the ducted fan by using the inlet total static pressure rake (26), and calculate the average airflow velocity and average flow rate by combining the corresponding cross-sectional area; Step 4: Measure the total temperature and total pressure between the ducted fan rotor blades and hub (17) and stator blades (21) using the total temperature and total pressure rake (27) at the rear end of the fan, and measure the total temperature and total pressure at the rear end of the stator blades (21) using the total temperature and total pressure rake (28) at the rear end of the stator, to obtain the pressure and temperature increase characteristics of the rotor blades and stator blades (21). Step 5: Measure the tension and torque of the ducted fan using a rotating balance (15), amplify and filter the output signal of the rotating balance (15) using a signal amplifier (16), and calculate the power and efficiency of the ducted fan in combination with the rotational speed. Step 6: Obtain static pressure data through the static pressure measuring point on the bottom resistance measuring plate (18) of the propeller cap, correct the tension measured by the rotating balance (15), and complete the comprehensive measurement of the aerodynamic performance of the ducted fan.

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