基于质量守恒原理的临界流喷嘴动态检定方法研究

The Critical Flow Nozzles Flying Test Method Based on the Principle of Mass Conservation

针对低雷诺数临界流喷嘴喉径小，几何测量困难，常用的负压式PVTt装置难以对喷嘴进行最大背压比试验等问题，设计了一种以步进电机为动力的主动活塞式气体流量校准器。依据流体力学质量守恒原理，提出按PcTt参数动态检定临界流喷嘴流出系数的方法，建立了数学模型。经比对验证，动态检定方法准确、可行，流出系数Cd的重复性达到（0．02～0．05）％。

In view of the shortcomings existed in the low reynolds number critical flow nozzles such as the difficuhies of geometric measurement in small throat radius and the test of back pressure ratio on existing PVTt standard facility, an the active piston flow comparator is developed. According to the principle of mass conservation, a flying test method based on PcTt is presented. Test results show that the flying test method is accurate and feasible. The repeatability of discharge coefficient Cd is up to （0. 02 -0. 05）%.