对ISO6358-1变压法的评说及建议

Comments and Proposals on ISO6358-1 Variable Upstream Pressure Test

针对变压法对两个流量特性参数C、b值进行均方根误差分析及测试都表明,测出C值是可信的;测b值时,仪表的测量精度等级宜使用特级,b值宜大于0.4,不宜测量有最低使用压力要求的气动元件的b值;即使对无最低使用压力要求的气动元件,也要注意对于上游压力p1较低,流通能力小的气动元件,由于雷诺数Re太小,会导致测出b值严重失真的问题。

Root-mean-square error analysis and practical experiments draw the following conclusions on the ISO6358-1 variable upstream pressure test. The sonic conductance, C, can be tested with high accuracy. The critical pressure ratio, b, should be tested by equipments of super class precision. The b value should be more than 0.4. The b value of parts with minimum pressure should not be tested by the variable upstream pressure test. Even for parts without minimum pressure, low upstream pressure and low flow-rate always lead to low Re value, which destroy the accuracy of b value.