亚临界流状态下燃气调压器流量系数的计算

介绍GB 27790-2011《城镇燃气调压器》中流量系数计算方法。提出3种亚临界流动状态下流量系数的计算方法:方法1是利用流量系数和形状系数的关系方程求解流量系数;方法2是利用GB/T 17213.9-2005《工业过程控制阀第2-3部分:流通能力试验程序》中试验方法求取流通能力系数,进而换算成流量系数;方法3是利用方法2求取临界压差比,进而获得形状系数,再计算流量系数。进行2个不同类型燃气调压器流量系数的试验,分析3种方法求得的流量系数的相对误差,结果表明:3种方法得到的流量系数的相对误差绝对值均在6%以内,形状系数的相对误差绝对值均在10%以内。方法3得到的流量系数的相对误差绝对值在1.5%以内,形状系数的相对误差绝对值在5%以内。方法3可以将流量系数测试对试验装置流量能力的要求降低50%以上,从而降低测试过程的能耗。

Calculation of Flow Coefficient of Gas Pressure Regulator under Subcritical Flow Condition

The calculation method of flow coefficient in City Gas Pressure Regulators(GB 27790-2011)is introduced.Three calculation methods of flow coefficient under subcritical flow condition are proposed.Method 1 is to use the relationship equation between the flow coefficient and the shape coefficient to solve the flow coefficient.Method 2 is to use the test method in Industrial-process Control Valves-Part 2-3:Flow Capacity-Test Procedures(GB/T 17213.9-2005)to obtain the flow capacity coefficient,and then convert it into the flow coefficient.Method 3 is to use method 2 to obtain the critical pressure difference ratio,and then obtain the shape coeffcient,and then calculate the flow coefficient.The flow coefficient test of two different types of gas regulators is carried out,and the relative error of the flow coefficient obtained by the three methods is analyzed.The results show that the absolute values of the relative errors of the flow coefficient and shape coefficient obtained by the three methods are all within 6%and 10%,respectively.The absolute values of the relative errors of the flow coefficient and shape coefficient obtained by the method 3 are within 1.5%and 5%,respectively.Method 3 can reduce the requirement of the flow coefficient test on the flow capacity of the test device by more than 50%,thereby reducing the energy consumption of the test process.