D300mm×2000mm圆管内旋转流切向速度特征的实验研究

Experimental study of the real tangential velocity in the circular pipe with D300mm×2000mm by HWA

采用热线风速仪(HWA,Hot Wire Anemometry)测量了D300mm×2000mm圆管内旋转流切向瞬时速度随时间的变化特征。测量结果表明在圆管的中心区域,瞬时切向速度随时间的波动变化较大,而靠近边壁区域瞬时切向速度随时间的波动变化较小,中心区域瞬时切向速度的脉动幅值远大于壁面区域的脉动幅值。通过对瞬时切向速度进行频谱分析可知,瞬时切向速度的波动频率沿径向和轴向基本一致,但在出口区域频率有所增大,圆管内的瞬时切向速度出现低频波动是旋转流的摆动导致的。

The real tangential velocity of swirling flow in the circular pipe with the diameter 300mm and the length 2000mm was measured by using Hot Wire Anemometry（HWA）.The results show the tangential velocity fluctuates obviously in the center region of the circular pipe,and a little fluctuation near the wall of the circular pipe.The amplitude in the center region is higher than that near the wall.By Fast Fourier Transform（FFT） to the real tangential velocities,the frequencies are similar along the radial direction and the axial direction,except in the region near the exit where the frequencies are increased largely.The quasi-periodic fluctuation of the real tangential velocity results from the oscillation of swirling flow.