为提高相控阵超声检测系统对风电叶片等大型构件的检测精度,设计了4种不同结构的矩形出水口喷嘴,通过数值仿真对比分析了各个喷嘴的流动特性。分析发现应用维多辛斯基曲线作为引导进行流道内表面设计的喷嘴,其流束发散最慢,射流最稳定。为降低加工成本,基于道格拉斯-普克算法将理想的维多辛斯基曲线简化为一种分段式折线,并进行试验验证。结果表明,简化后的喷嘴与应用维多辛斯基曲线的喷嘴性能接近,射流稳定性好,具有实际应用价值。

In order to improve the detection accuracy of phased array ultrasonic testing system for large components such as wind turbine blades, four kinds of rectangular outlet nozzles with different structures were designed in this paper. The flow characteristics of each nozzle are compared and analyzed by numerical simulation. It is found that the nozzle with the inner surface of the flow channel designed by using the Witozinsky curve as the guide has the slowest beam divergence and the most stable jet. In order to reduce the processing cost, the ideal Witozinsky curve was simplified as a piecewise broken line based on the Douglas-Pucker algorithm, and the experimental verification was carried out. The results show that the performance of the simplified nozzle is close to that of the nozzle using the Witozinsky curve, and the jet stability is good, which has practical application value.