Wind tunnel test method for coaxial double-rotor hub model of helicopter

Abstract

The invention discloses a wind tunnel test method for a coaxial double-rotor hub model of a helicopter, and belongs to the field of hub wind tunnel test methods. According to the method, a large-advance-ratio coaxial double-rotor hub model flow mechanism and a pneumatic interference test can be carried out. The method comprises the following steps of firstly, installing a test bed in a wind tunnel, and carrying out coaxial synchronous reverse rotation motion of the model through the test bed; secondly, monitoring a vibration level of the test bed in real time by a vibration monitoring system,and researching dynamic characteristics of the test bed; thirdly, measuring six force factors of the model by a box type balance, measuring a flow field of the model by a PIV flow field measuring system, and measuring the surface pressure of the model by an electronic scanning pressure measuring system or a pressure sensor; fourthly, during a test process, replacing components of the coaxial double-rotor hub model according to the need in order to research the aerodynamic characteristics of the model with different appearances or different flow control modes; and finally, obtaining the aerodynamic characteristics of the model. According to the method, a problem of measurement of the aerodynamic characteristics of the rotating coaxial double-rotor hub model is solved.

Description

technical field [0001] The invention relates to the field of propeller hub wind tunnel test methods, in particular to a wind tunnel test method for studying rotatable, different propeller hub shapes and coaxial dual-rotor propeller hub models with flow control technology applied. Background technique [0002] The coaxial rigid rotor technology can significantly increase the flight speed of the helicopter, but its hub system has two hubs with opposite rotation directions, which has a complex shape and is higher than ordinary rotor hubs. The impact is serious, and its resistance usually accounts for about 50% of the total aircraft resistance. Large hub resistance is an important factor limiting the maximum flight speed and maximum range of coaxial rigid rotor high-speed helicopters. Therefore, reducing the coaxial rigid rotor system hub Resistance is one of the key issues that must be solved to realize the high speed and long range of this type of helicopter. [0003] However...

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Problems solved by technology

[0002] The coaxial rigid rotor technology can significantly increase the flight speed of the helicopter, but its hub system has two hubs with opposite rotation directions, which has a complex shape and is higher than ordinary rotor hubs. The impact is serious, and its resistance usually accounts for about 50% of the total aircraft resistance. Large hub resistance is an important factor limiting the maximum flight speed and maximum range of coaxial rigid rotor high-speed helicopters. Therefore, reducing the coaxial rigid rotor system hub Resistance is one of the key issues that must be solved to achieve high speed and long range of this type of helicopter

[0003] However, due to the fact that domestic research on coaxial rigid rotor hubs is in its infancy, although simple wind tunnel test studies have been carried out, such as "He Long, Wang Chang, Tang Min, etc. Tests on drag characteristics of coaxial rigid rotor hubs [J]. Journal of Nanjing University of Aeronautics and Astronautics, 2016, 48(4): 530-535. (DOI: 10.16356 / j.1005-2615.2016.04.013)", however, the wind tunnel test has the following shortcomings: the size of the hub model It is too small, the speed is low, the test Reynolds number is too small, the accuracy of the test results is not high, and only the overall aerodynamic force can be measured, and the aerodynamic force of different components cannot be measured separately; the gap between the test model components is large, resulting in the actual The shape does not conform to the aerodynamic shape; the test method is not systematic, the shape of the hub only includes the upper and lower hub fairing + no intermediate shaft fairing + tower seat, the upper and lower hub fairing + intermediate shaft fairing + tower seat, no Including upper and lower propeller hub + no intermediate shaft fairing, propeller root and application of flow control technology, and the model has only one attitude angle (pitch angle, sideslip angle, and roll angle are all 0°); the test measurement content is only Including force measurement and model surface flow display, excluding PIV space flow field measurement and surface pressure measurement between components

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