可调文氏管流量控制及其在变马赫数风洞中的应用

Flow Control of Throttleable Venturi Nozzle and Its Application in Varying-Mach-Number Wind Tunnel

关键词:  可调文氏管  流量控制  标定  不确定度  变马赫数风洞

Key words:  Throttleable venturi nozzle  Flow rate control  Calibration  Uncertainty  Varying-Mach-number wind tunnel

摘要:

为了实现变马赫数风洞运行过程中流量的连续精确控制，设计了连续可调文氏管。利用减压器保持可调文氏管上游压力稳定不变，通过伺服电机控制针锥前后移动调节文氏管节流面积连续变化，从而实现流量连续变化。针锥与可调文氏管型面经过设计，保证可调文氏管节流面积随针锥位移线性变化，提高了流量控制精度。使用标准文氏管对可调文氏管进行流量标定，标定结果显示：随针锥位置变化，可调文氏管流量系数略有变化，变化范围为0.97~0.99；可调文氏管流量控制重复性非常好，流量控制的不确定度均小于2%。通过可调文氏管的流量连续控制，变马赫数风洞实现了马赫数2~4对应模拟参数的连续变化。

Abstract:

The throttleable venturi nozzle was designed for the mass flow rate continuous and precise control of varying-Mach-number wind tunnel. The pressure reducer was used for maintaining pressure stable of throttleable venturi nozzle upstream， and the throttle area was adjustable continuously through the movement of plug driven by servo motor. Thus， continuous variations of the flow was realized. The throttle area of throttleable venturi nozzle changes linearly with plug displacement for the profiles of plug and venturi nozzle were designed， for which the precision of flow rate control was improved. The standard venturi tube was used for flow rate calibrating， and it is shown that the discharge coefficient of throttleable venturi nozzle changes slightly with plug position in the range of 0.97~0.99. Throttleable venturi nozzle shows excellent repeatability in flow rate control. The results show that uncertainty of mass flow rate measurement is less than 2%. The throttleable venturi nozzle has been used for the flow rate control in vary-Mach-number wind tunnel， and the continuous variation of the corresponding simulation parameters of Mach 2~4 have been achieved successfully.