空腔内旋转流动LDA整场测量及实验Re数恒定方法

空腔内的旋转流动常常涉及二次流、旋涡破裂等复杂问题。在整场流动实验测量中 ,必须长时间保持恒定工况。目前文献中的作法一般是采用高精度的恒温水域 ,但系统复杂、控制精度受限制。笔者介绍了一种根据实测温度调频变速保持实验Re数不变的方法。实验表明 ,该方法简单易行 ,并能将流动在长时间内高精度地保持在同一工况Re数内。最后给出了采用这种方法的整场和旋涡破裂区域内速度分布的LDA测量结果。

LDA full field measurement of swirling flow inside container and the method to keep constant experiment Re number

Rich complicated flow problems present in swirling flow inside container,secondary flows,vortex breakdown,to name a few.However,constant working condition is necessary and important for full field measurements.The popular method to keep working condition constant used in most experimental apparatuses is to place a high precision constant temperature water tank outside of the flow field.But it makes the measurement system complicated,and the controllable precision is limited.The method of adjusting the rotating rate dependent on measured temperature to keep Reynolds number is presented here.It is experimentally testified that the method is convenient to be used,and can keep the flow pattern at the same Reynolds number with high precision for long time.By means of the method,the full field LDA (Laser Doppler Anemometer) measurements of swirling flow inside cylindrical container are shown here,as well as measurement results of flow field inside vortex breakdown region with large number of measurement points.