采用长细管法进行脉动压力转捩探测的实验研究

为了简便地使用测量模型表面脉动压力特征的方法探测边界层转捩位置,需要研究脉动压力传感器接在传统测压模型外的适用性,即通过长细管将模型表面的脉动压力信号传递到脉动压力传感器上的方式是否可得到转捩的特征信号。首先采用信号发生器驱动扬声器,在无风条件下,测量了长细管对不同频率声压信号的传递损失情况。证明了所采用的长细管系统具有合适的工作频带。然后在西北工业大学NF-3低速风洞二元实验段、实验风速为30m/s的条件下,对弦长为800mm、展长为1.6m的翼型模型沿弦向进行了脉动压力信号测量,并通过改进的数据处理技术判断了模型表面的转捩位置。研究结果表明,采用长细管系统进行脉动压力方法转捩探测具有一定应用价值,值得进一步深入研究。

Experimental study on pressure fluctuation sensor-based diagnostic for boundary layer transition with long-fine tubing system

Low speed flow transition zone of boundary layer can be detected by means of pres-sure fluctuation measurement over the surface of the test model.It is convenient that fluctuation pressure transducers are arranged outside the model through long-fine tubing system.The distor-tion of pressure signal caused by the tubing system should be recognized.Under the static condi-tion(V= 0m/s),the authors measured a series of sound signals over an airfoil model surface through the tubing system.The sound signal source come from a speaker actuated by a signal generation.The model chord length is 0.8m and the model span is 1.6m in length.The tubes are about 1.2m long and their inner diameters are 0.8mm.The tubing system has proved to be able to transmit the characteristics of the surface pressure fluctuation for the transition detection.Un-der the condition of section flow velocity V= 30m/s,signals of the surface pressure fluctuation transmitted along the chord of the model were measured and the boundary layer transition zones were located.This experiment was conducted in NF-3 low-speed wind tunnel of Northwestern Polytechnical University.The authors suggest that the pressure fluctuation transition diagnostic method with long-fine tubing system is promising and further researches should be carried out.