变面积临界流文丘里喷嘴特性研究

Research on characteristics of variable area critical flow Venturi nozzle

针对目前气体流量计量领域临界流文丘里喷嘴临界流量不可调节或调节困难的情况,提出一种喉部过流面积可调节的变面积临界流喷嘴。通过结构分析、建模计算、流体力学Fluent仿真等方式,对棒状节流体、锥状节流体、台锥状节流体三种不同调节方式进行研究分析。结果表明:采用三种不同节流体的变面积临界流文丘里喷嘴均能实现临界流流量的调节,在背压比小于最大允许背压比后,流量保持一稳定值,基本不变。建模计算得到的理论值与Fluent仿真到的数据较为符合。

In order to regulate critical flow rate of traditional critical flow Venturi nozzles, a new variable throat- area critical flow Venturi nozzle is proposed, throat area of which can be adjusted. Three different adjusting methods, including rod-style method, cone-style method and hybrid-style method, are analyzed by means of structure analysis, modeling calculation and fluid dynamics Fluent simulation. Results show that the critical flow of the new variable critical flow Venturi nozzles can be regulated well by using three different methods and when back-pressure ratio is smaller than the maximum allowable back pressure ratio, the flow rate of the new nozzle is almost kept constant, though the back-pressure ratio is still descending. And Fluent results coincides with the theoretical value calculated by modeling.