CN216669208U

CN216669208U - Ventilation force measurement test model internal resistance measuring device

Info

Publication number: CN216669208U
Application number: CN202022478458.1U
Authority: CN
Inventors: 周键; 刘进征; 刘磊; 钱丹丹
Original assignee: China Academy of Aerospace Aerodynamics CAAA
Current assignee: China Academy of Aerospace Aerodynamics CAAA
Priority date: 2020-10-30
Filing date: 2020-10-30
Publication date: 2022-06-03
Anticipated expiration: 2030-10-30

Abstract

A ventilation force-measuring test model internal resistance measuring device is used for measuring ventilation force-measuring model wind tunnel test internal resistance and belongs to the technical field of wind tunnel tests. The utility model comprises a force measuring balance, a balance protective cover, a support rod, a rectifying block, a throttling block and a total pressure rake, wherein the force measuring balance, the balance protective cover, the support rod and the throttling block are all arranged inside a to-be-tested ventilation force measuring test model, the support rod is connected with the force measuring balance, the rectifying block and the throttling block are arranged in an inner cavity of the to-be-tested ventilation force measuring test model and are connected with the to-be-tested ventilation force measuring test model, and the balance protective cover is arranged outside the force measuring balance. The front edge and the rear edge of the rectifying block are in smooth transition with the inner cavity of the model, the section of the rectifying block is in a sawtooth shape and is positioned at the upstream of the throttling block, the front edge of the inner cavity of the throttling block is a diameter changing section and is tangent to the inner cavity of the test model, the rear edge of the rectifying block is a cylindrical section with equal diameter and is flush with the tail end face of the model, and the total pressure rake is connected with the supporting rod through a support.

Description

Ventilation force measurement test model internal resistance measuring device

Technical Field

The utility model relates to a ventilation force-measuring test model internal resistance measuring device, which is used for measuring the ventilation force-measuring model internal resistance in a wind tunnel test and belongs to the technical field of wind tunnel tests.

Background

When the air-breathing aircraft force-measuring wind tunnel test is carried out, in order to ensure that the internal and external flow fields of the aircraft are similar, the test model needs to be designed into a ventilation state without adopting a cone blocking mode, so that the influence of interference of the internal and external flow fields is reduced. In the ventilation model, airflow rushes into the air inlet channel from the air inlet to form a pipe flow, and then flows out from the tail nozzle, a certain amount of resistance is generated by the flow channel in the process, the resistance cannot be reflected in the real flight of the aircraft, and the resistance needs to be deducted when lift-drag characteristic analysis is carried out, so that the measurement of internal resistance in the air-breathing aircraft force measurement test is indispensable.

At present, the method for measuring the internal resistance of the ventilation and force measurement model is to measure the total static pressure of the cross section of an outlet, and the total pressure calandria and the static pressure calandria are usually adopted, the calandria is fixed on a support rod through a base and is in a cantilever beam form, the support rigidity is small, in addition, the local airflow flow rate is high, the phenomenon of shaking occurs after the calandria is disturbed by airflow, the total static pressure measurement error is large, and the internal resistance calculation error is increased; in addition, because the total static pressure calandria is located in the limited space between the inner cavity of the model and the support rod, the model is easy to collide with the calandria after being stressed and deformed, so that the force measurement test data is influenced, and meanwhile, the existence of the total static pressure calandria also influences the pressure measurement. In summary, the internal resistance measurement result of the traditional total static pressure pipe arrangement method is poor in accuracy, and only can provide reference for engineering application, so that the requirement for rapid development of high-speed wind tunnel tests is difficult to meet.

SUMMERY OF THE UTILITY MODEL

The technical problem solved by the utility model is as follows: the device can simply and effectively obtain the channel resistance in the test model in the ventilation force-measuring test, solves the problems of complexity, large error and the like of the traditional total static pressure calandria measuring method, and solves the internal resistance of the test model by replacing the static pressure calandria measurement with the wall static pressure measurement.

The technical solution of the utility model is as follows: a ventilation force-measuring test model internal resistance measuring device comprises a force-measuring balance, a supporting rod, a rectifying block, a throttling block and a total pressure rake, wherein the force-measuring balance is used for measuring six component forces and moments of a test model;

the force measuring balance, the support rod, the rectifying block and the throttling block are all arranged in the to-be-measured ventilation force measuring test model, the force measuring balance is fixedly connected to the front portion of the support rod, the rectifying block is located at the upstream of the throttling block, and the throttling block is located at an outlet of an inner cavity of the to-be-measured ventilation force measuring test model and is fixedly connected with the to-be-measured ventilation force measuring test model;

the total pressure rake is fixedly connected with the supporting rod through a support.

Further, the balance protection cover is used for preventing the balance from being impacted by airflow; the balance protection cover is arranged outside the force measuring balance and is connected with the to-be-tested ventilation force measuring test model.

Further, the rectifying block and the throttling block are coaxially arranged in an inner cavity of the model of the to-be-tested ventilation force-measuring test model.

Furthermore, the front edge and the rear edge of the rectification block are in smooth transition with the inner cavity of the ventilation and force measurement test model to be tested, and the section of the rectification block is in a sawtooth shape.

Furthermore, the throttling block is positioned at the tail part of the inner cavity of the model of the to-be-tested ventilation force-measuring test, and the tail end surfaces of the throttling block and the model are flush.

Furthermore, the front edge of the inner cavity of the throttling block is a diameter change section and is tangent to the inner cavity of the to-be-tested ventilation force-measuring test model, and the rear edge of the inner cavity of the throttling block is an equal-diameter cylindrical section.

Furthermore, static pressure hole measuring points for measuring static pressure of the section of the outlet of the inner cavity of the model are distributed on the outer surface of the supporting rod.

Further, the strut radius is set to R₁The radius of the front edge of the throttling block is set as R₂The trailing edge radius of the throttle block is set to be R₃And satisfies the relation: r₂>R₃>R₁。

Furthermore, the measuring section is located on the equal straight section of the rear edge of the throttling block, and the distance L between the measuring section and the tail end face of the to-be-measured ventilation force-measuring test model is-2-10 mm.

Furthermore, the static pressure measuring points are located on the outer surface of the supporting rod and are evenly distributed along the circumferential direction of the outer surface of the supporting rod, and the number i of the cross-section measuring points is larger than or equal to 4.

Furthermore, the total pressure measuring points and the static pressure measuring points are located at different circumferential positions of the same section, the measuring points are uniformly distributed along the circumferential direction through the measurement of the total pressure rake, the number i of the section measuring points is more than or equal to 4, and the circumferential radius R of the total pressure measuring points is₄≈(R₃+R₁)/2；R₁Is the strut radius, R₃Is the trailing edge radius of the throttle block.

Compared with the prior art, the utility model has the advantages that:

(1) the static pressure is measured by adopting the wall surface, and the static pressure measurement precision is high, so that the reliability of the internal resistance measurement result is high; the static pressure rake is not required to be designed and processed, the cost is low, and the reliability is high.

(2) The utility model can not reserve space for the pressure measuring calandria, the distance between the inner cavity of the model and the support rod can refer to the conventional force measuring test, the support rod has large diameter and strong support rigidity relative to the pressure measuring calandria method, and the measurement error caused by model shake in the test process is reduced.

(3) According to the utility model, for a large slenderness ratio and large lifting body model, the measurement section can be arranged 0-2 mm outside the outlet of the inner cavity of the model, so that the severe shaking and loaded deformation of the model are avoided to be contacted with the total pressure rake, and the defects of wind tunnel impact damage risk and contact interference of the pressure measuring rake are eliminated.

(4) According to the utility model, the throttling block with a special structure is designed according to the requirement, and the positions of two pressure measuring sections are reasonably selected through a large number of tests, so that the precision and the accuracy of calculation and measurement are greatly improved, and the measurement reliability is improved.

Drawings

FIG. 1 is a diagram of an internal resistance measurement device of a model for a ventilated dynamometric test of the present invention;

FIG. 2 is a schematic diagram of the characteristic dimensions of the device of the present invention.

Detailed Description

In order to better understand the technical solutions, the technical solutions of the present application are described in detail below with reference to the drawings and specific embodiments, and it should be understood that the specific features in the embodiments and examples of the present application are detailed descriptions of the technical solutions of the present application, and are not limitations of the technical solutions of the present application, and the technical features in the embodiments and examples of the present application may be combined with each other without conflict.

The following describes in further detail an internal resistance measuring device of a ventilation dynamometry test model provided in an embodiment of the present application with reference to the drawings of the specification.

In the scheme provided by the embodiment of the application, as shown in fig. 1, the internal resistance measuring device of the ventilation dynamometric test model is shown, and the resistance of the channel in the model is obtained by measuring the wall static pressure of the outlet section of the inner cavity at the tail of the ventilation dynamometric model and the total pressure of the local main flow. The internal resistance measuring device of the ventilation force-measuring test model comprises a force-measuring balance, a balance protective cover, a support rod, a rectifying block, a throttling block and a total pressure rake, wherein the force-measuring balance, the balance protective cover, the support rod and the throttling block are all arranged inside the ventilation force-measuring test model to be tested, the support rod is connected with the force-measuring balance, the rectifying block and the throttling block are arranged in an inner cavity of the ventilation force-measuring test model to be tested and are connected with the ventilation force-measuring test model to be tested, and the balance protective cover is arranged outside the force-measuring balance. The front edge and the rear edge of the rectifying block are in smooth transition with the inner cavity of the model, the section of the rectifying block is in a sawtooth shape and is positioned at the upstream of the throttling block, the front edge of the inner cavity of the throttling block is a diameter changing section and is tangent to the inner cavity of the test model, the rear edge of the rectifying block is a cylindrical section with equal diameter and is flush with the tail end face of the model, and the total pressure rake is connected with the supporting rod through a support.

In the ventilation force-measuring test, airflow is flushed into an inner cavity through a model air inlet and then discharged through a tail nozzle, as shown in fig. 1, an internal force-measuring balance is used for measuring six-component force and moment of a test model, a balance protective cover is used for preventing the balance from being impacted by the airflow, and a support rod is used for supporting the balance and is provided with static pressure hole measuring points on the outer surface; the rectifying block and the throttling block are coaxially arranged in an inner cavity at the tail part of the test model, the tail end faces of the rectifying block and the throttling block are flush, the front edge of the inner cavity of the rectifying block is tangent to the inner cavity of the test model, the rear edge of the inner cavity of the rectifying block is an equal straight section, and the middle of the inner cavity of the rectifying block is a smooth shrinkage curve section.

FIG. 2 is a schematic diagram showing the characteristic dimensions of the device of the present invention, wherein the radius of the strut is set to R₁The radius of the front edge of the throttling block is set as R₂The trailing edge radius of the throttling block is set as R₃(the tail outlet radius of the inner cavity of the model) satisfies the relation: r₂>R₃>R₁。

The static pressure measuring point is positioned on the outer surface of the support rod, the measuring section B-B is positioned on the equal-diameter cylindrical section of the inner cavity of the throttling block, which is close to the tail end face of the model, and the distance L from the measuring section B-B to the tail end face of the model is-2-10 mm, namely the measuring section can be positioned at the position which is 2mm to 10mm from the outlet of the inner cavity of the model. Wall static pressure measuring points are uniformly distributed in the circumferential direction, and the number i of the cross-section measuring points is more than or equal to 4; in the test process, the wall static pressure P at the measured section of the model is obtained through pressure measurement_i。

The total pressure measuring points and the static pressure measuring points are positioned on the same cross section, in order to avoid the interference of the total pressure harrow to the static pressure measuring points, the positions of the total static pressure measuring points are arranged in a cross distribution (such as a B-B cross section shown in figure 1), and the circumferential radius R of the total pressure measuring points is₄≈(R₃+R₁) And 2, the total pressure rake is a stainless steel pipe, the rear edge of the total pressure rake is fixedly connected with the supporting rod through a support, and the total pressure Pt at the section of the model to be measured is obtained through pressure measurement_i。

By measuring the total static pressure measurement value of the cross section, the expression of the Mach number at the measuring surface is obtained according to the isentropic relation as follows (if supersonic flow, pitot pressure conversion is firstly carried out, and the detailed description is not carried out here):

wherein:

to measure the average static pressure of the strut wall at section B-B,

the local average total pressure flowing in the tail part of the model,

to measure the average mach number of the cross section. Calculating the expression of the internal resistance of the to-be-measured ventilation dynamometric test model by using the momentum conservation theorem as follows:

wherein: x_inThe internal resistance coefficient of the ventilation force measurement test model to be measured; m_∞Is the wind tunnel incoming flow Mach number, P_∞The static pressure of wind tunnel incoming flow and Se are the area of a measuring section (outlet) of a flow passage in the ventilation force-measuring test model.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Those skilled in the art will appreciate that those matters not described in detail in the present specification are not particularly limited to the specific examples described herein.

Claims

1. The utility model provides a ventilative dynamometry test model internal resistance measuring device which characterized in that: the device comprises a force measuring balance for measuring six component forces and moments of a test model, a support rod for supporting the force measuring balance, a rectifying block for rectifying the flow of an inner flow channel, a throttling block for an outlet of the inner flow channel and a total pressure rake for measuring the total pressure of the section of the outlet;

2. The apparatus of claim 1, wherein the apparatus comprises: the balance protection cover is used for preventing the balance from being impacted by airflow; the balance protection cover is arranged outside the force measuring balance and is connected with the to-be-tested ventilation force measuring test model.

3. The apparatus of claim 1, wherein the apparatus comprises: the rectifying block and the throttling block are coaxially arranged in an inner cavity of the model of the to-be-tested ventilation force-measuring test model.

4. The apparatus of claim 1, wherein the apparatus comprises: the front edge and the rear edge of the rectifying block are in smooth transition with the inner cavity of the to-be-tested ventilation force-measuring test model, and the section of the rectifying block is in a sawtooth shape.

5. The apparatus of claim 1, wherein the apparatus comprises: the throttling block is positioned at the tail part of the inner cavity of the model of the to-be-tested ventilation force-measuring test, and the tail end surfaces of the throttling block and the model are flush.

6. The apparatus of claim 1, wherein the apparatus comprises: the front edge of the inner cavity of the throttling block is a diameter change section and is tangent to the inner cavity of the to-be-tested ventilation force-measuring test model, and the rear edge of the inner cavity of the throttling block is an equal-diameter cylindrical section.

7. The apparatus of claim 1, wherein the apparatus comprises: static pressure hole measuring points for measuring static pressure of the section of the outlet of the inner cavity of the model are distributed on the outer surface of the supporting rod.

8. The apparatus of claim 1, wherein the apparatus comprises: the radius of the strut is set as R₁The radius of the front edge of the throttling block is set as R₂The trailing edge radius of the throttle block is set to be R₃And satisfies the relation: r₂>R₃>R₁。

9. The apparatus of claim 7, wherein the apparatus comprises: the measuring section is located on the equal straight section of the rear edge of the throttling block, and the distance L between the measuring section and the tail end face of the to-be-measured ventilation force-measuring test model is-2-10 mm.

10. The apparatus of claim 7, wherein the apparatus comprises: the static pressure measuring points are positioned on the outer surface of the supporting rod and are uniformly distributed along the circumferential direction of the outer surface of the supporting rod, and the number i of the cross-section measuring points is more than or equal to 4; the total pressure measuring points and the static pressure measuring points are located at different circumferential positions of the same section, the measuring points are uniformly distributed along the circumferential direction through the measurement of the total pressure rake, the number i of the section measuring points is more than or equal to 4, and the circumferential radius R of the total pressure measuring points is₄≈(R₃+R₁)/2；R₁Is the strut radius, R₃Is the trailing edge radius of the throttle block.