后混合磨料水射流除鳞喷嘴内部流场数值模拟

Numerical simulation of internal flow field for post-mixed abrasive water jet descaling nozzle

基于CFD多相流欧拉模型,针对后混合式磨料水射流除鳞喷嘴中磨料与水混合均匀性差、射流能量利用率低的缺点,应用Fluent软件对磨料侧进式、切进式和平行多射流式3种进料方式的喷嘴进行三维数值模拟,通过喷嘴内部流场速度矢量图分析了3种进料方式下高压水与磨料的作用机理,并通过磨料体积分数云图比较了流场的均匀性.结果表明:与磨料侧进式喷嘴相比,磨料切进式和平行多射流式喷嘴能够改善磨料与水的混合效果,使流场内磨料分布均匀.但切进式喷嘴会增加喷嘴内部的磨损,需要采用更耐磨的材料.与前两种喷嘴相比,平行多射流式喷嘴可得到磨料与水最好的混合均匀性,实际应用中还可以根据需要对水射流的流量及作用方式进行调节.

For the shortcomings,such as low efficiency of jet energy and poor uniformity of water and abrasive in the post-mixed abrasive water jet descaling nozzle,three kinds of structures of the nozzle were put forward: the side feed nozzle,the tangential feed nozzle,and the parallel multi-jet nozzle. Based on the CFD Eulerian multiphase flow model,the 3-dimensional numerical simulation of the three kinds of structures was conducted with the FLUENT software. And the acting mechanism of the high-pressure water with the abrasive was analyzed through the velocity vector of the flow field inside the nozzle. The uniformity of the flow field was compared by analyzing the volume fraction contours of abrasive. Results show that compared with the side feed nozzle,the tangential feed nozzle and the parallel multi-jet nozzle can improve the mixing effect and obtain a rather uniform abrasive distribution. Whereas,the tangential feed nozzle can augment the internal wear of the nozzle,which needs a kind of more wear-resistant material. Compared with the former two structures,the mixing effect of the parallel multi-jet nozzle is perfect and the water jet flow as well as the acting mode could be adjusted according to the need in practical application.