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Method for measuring directional speed of airflow in air system

A technology for measuring airflow direction and velocity, which is applied in the measurement of fluid velocity by differential pressure, which can solve the problems of complicated measurement, high measurement cost, and complicated operation, and achieve the effect of strict conditions of use, high cost of use, and high accuracy.

Inactive Publication Date: 2019-11-19
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to avoid the deficiencies of the prior art, the present invention proposes a method for measuring the velocity of the airflow direction in the air system, which overcomes the problems of complicated measurement, high measurement cost and complicated operation of the existing flow velocity measurement method

Method used

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  • Method for measuring directional speed of airflow in air system
  • Method for measuring directional speed of airflow in air system
  • Method for measuring directional speed of airflow in air system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Attached figure 1 , The axial air intake reaches the stationary swirl disk 1 as shown in the figure, and then passes through the oblique hole 2. The direction of the airflow changes and has a circumferential velocity Total speed V out The angle with the axial direction is θ. The airflow deflection angle θ is related to the size and direction of the incoming flow velocity, the deflection angle of the pre-rotation hole, and the aspect ratio of the pre-rotation hole. When the flow velocity and direction are determined, when the aspect ratio of the pre-rotation hole reaches a certain value After the value, the air flow deflection angle θ is equal to the pre-rotation hole deflection angle.

[0052] Attached figure 1 It can also be known that the direction velocity of the airflow is obtained as the circumferential velocity The size of is very important to obtain the airflow characteristics. The airflow rotation ratio, airflow and axis angle can be calculated, and then the flow...

Embodiment 2

[0060] As shown in the figure, the air flow enters axially and passes figure 2 After the swirling orifice is shown, the airflow direction changes, and a certain amount of circumferential velocity is obtained. When it is necessary to know the circumferential velocity of the airflow , You can choose to use this direction speed measurement method to obtain the circumferential speed the size of. The specific parameters of the swirl orifice are shown in Table 2:

[0061] Table 2: Specific parameters of swirl orifice

[0062] Swirl orifice diameter 304mm Swirl aperture position 115mm Swirl hole diameter 7mm Axial included angle of swirl hole 45°

[0063] Step 1: Choose a suitable static pressure measuring point on the pitot tube. Since the swirl orifice is an axially pre-swirl air intake, the axial velocity and circumferential velocity of the airflow are relatively large. Numerical calculation results of multiple working conditions show that the radial velocity after the swirl...

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Abstract

The invention relates to a method for measuring a directional speed of airflow in an air system. A directional speed can be directly obtained by measuring two pressures, namely a differential pressure. Measurement is simple, and the measurement cost is greatly reduced. Through comparison, it is found that the maximum absolute deviation between the measured value obtained by the directional speed measuring method and the speed in the same direction obtained through traditional five-hole needle analysis is 4.72m / s, the maximum relative deviation is 5.96%, the accuracy of the method is very high,and a directional speed of airflow can be accurately obtained. In the prior art, there is no method for measuring the directional speed of airflow, a three-dimensional flow speed measuring instrumentneeds to be used during speed measurement, and the speed in each direction is determined according to a three-dimensional flow velocity result, which leads to problems such as high use cost, strict use conditions and complex operation. The problems in the prior art are solved by using the method of the invention.

Description

Technical field [0001] The invention belongs to the field of aeroengine air systems, and relates to a method for measuring the direction and speed of airflow in an air system. Background technique [0002] Increasing the gas temperature in front of the aero engine turbine inlet can correspondingly increase the thrust-to-weight ratio of the aero engine, and the engine thrust corresponding to an increase of 55°C in the gas temperature in front of the turbine inlet can increase by about 10%. At present, the temperature of the turbine front edge of modern aero-engines has reached 2000K, which far exceeds the upper limit of the temperature resistance of the metal materials used in the engine. It is becoming more and more difficult to improve the performance of the engine by improving the temperature resistance of the materials. The low-temperature air is extracted in the engine and the high-temperature parts of the turbine are effectively cooled through the internal air flow system of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01P5/16
CPCG01P5/16
Inventor 刘高文张苗冯青
Owner NORTHWESTERN POLYTECHNICAL UNIV