基于超声多普勒测速法对二维涡流场初步测量研究

为研究第四代先进反应堆燃料组件、散裂靶窗及换热器等复杂部件内的涡流场，利用超声多普勒测速（UDV）法在四直叶轮搅动装置上开展了涡流流场的测量实验。通过径向和轴向流场的矢量合成，获得了轴向截面上二维涡流流场分布。结果表明：轴向截面上流速随雷诺数的增大而增大；在叶轮上、下两侧区域分别存在较大的漩涡，上漩涡为逆时针方向，下漩涡为顺时针方向；截面上流速分布存在较大梯度，且湍流强度随雷诺数的增大逐渐增大，在与叶轮等高处流速很大，而在叶轮上、下两侧区域流速较小，这表征了涡流场的变化特性，说明UDV测量技术能用于复杂流场测量。

Preliminary Study on Measurement of Two-dimensional Vortex Flow Field Based on Ultrasonic Doppler Velocimetry Method

In order to measure the vortex flow filed in the components of fuel assembly, spallation target and heat exchanger for Generation-Ⅳ nuclear reactors, the vortex flow field was measured in an agitation facility driven by four-straight impeller through ultrasonic Doppler velocimetry (UDV) method. The two-dimensional vortex flow mapping in vertical section was acquired, which was based on vector synthesis in radial direction and axial direction. The results indicate that the flow velocity increases with Reynolds number. Of two large vortexes, one occurs in the upper fluid domain with counterclockwise direction, and the other below with clockwise direction, exists on both sides of the impeller. In addition, the large velocity gradient exists and the turbulence intensity increases with Reynolds number. The velocity in the depth of impeller is great while it is very small on both upper and down sides of the impeller. It greatly illustrates the variation characteristics of the vortex flow filed, and the UDV method can be used for measurement of complicated flow field.