同孔板一样,用标准喷咀测量气体、蒸汽流量,当工况压力变化时,通常要对测量结果进行密度修正。压力变化较大时,流束膨胀系数的变化也应当考虑。下面就此问题进行一些探讨。一、流束膨胀系数ε的简化表达式国家标准中给出的ε计算公式较复杂,不便讨论。在此,利用国家标准附录中给出的标准喷咀的流束膨胀系数图(以下简称“ε图”) As with the orifice plate, the standard nozzle is used to measure the gas and vapor flow. When the working pressure changes, the density of the measurement result should be usually corrected. Large changes in pressure, the beam expansion coefficient changes should also be considered. Here’s some discussion on this issue. A simplified expression of the beam expansion coefficient ε The formula given in the national standard ε is more complicated and inconvenient to discuss. Here, using the standard nozzle given in the national standard flow expansion coefficient chart (hereinafter referred to as “ε map”)