圆锥形入口小喉径临界流喷嘴数值模拟与设计

Numerical simulation and design of small diameter critical venturi nozzles with conical inlet

设计了一种具有圆锥形入口的小喉径临界流喷嘴,采用Fluent进行数值模拟实验,研究其几何结构即入口角、入口段长度、喉部长度、扩散角和扩散段长度等参数对流出系数的影响。通过仿真分析对圆锥形入口喷嘴的几何结构进行了设计和优化。结果表明,喉部长度与入口角大小对流出系数影响较大,喉部长度与流出系数为负线性相关;流出系数随入口角的增大,先增大后减小,在17.5°时达到最大值;流出系数随扩散角的增大而增大,增长率却随扩散角的增大而减小;当扩散角大于3°,扩散段长度对流出系数的影响不明显。

A small diameter critical venturi nozzle with conical inlet is designed. The influence on the discharge coefficient caused by the geometrical structure, such as inlet angle, inlet length, throat length, divergence angle and divergence length, is investigated by numerical simulation by using Fluent. The geometrical structure of critical venturi nozzles with conical inlet is optimized according to the numerical simulation data. The results show that the throat length and the inlet angle have important influence on the discharge coefficient. The relationship is negative linear correlation between discharge coefficient and throat length. The discharge coefficient increases as the divergence angle increasing, however, the grow rate has the opposite trend. The divergence length has no obvious effects on the discharge while the divergence angle exceeds 3°.