真实气体的普适管道压降方程

A universal equation of pipe pressure drop for real gas flow

程惠亭-郝文斌可压缩气体管道压降公式基于理想气体假设,这对高压下的真实气体管道流动存在一定的误差,因此有必要对其进行改进以便减少这个误差。文中通过引入气体压缩因子Z导出了修正的程惠亭-郝文斌公式,以适用于真实气体管道压降计算。给出微分方程的建立和求解过程,并用文中公式、等温公式和潘汉德公式分别计算起始压力范围为1.0—8.0 MPa内的天然气管道压降,计算和分析误差。结果表明:文中给出的公式计算结果和潘汉德公式的计算结果非常接近,对管道规格、气体类型和压降范围都没有限制,应用范围远大于现有的大多数专用经验公式,可用于高压下真实气体的管道压降计算。

As the universal equation of pipe pressure drop for gas flow presented by Cheng huiting & Hao Wenbin(Cheng-Hao equation) is based on the ideal gas state equation, it will cause larger error for real gas flow at high pressure pipe. So it is necessary to modify the equation to reduce the error. In this paper, a modified Cheng-Hao equation was derived by introducing compressibility factor Z. The modified equation derivation process including the establishing and solving of differential equation was given. In the start pressure range 1.0-8.0 MPa, sets of pipe pressure drops were calculated by the new modified Cheng-Hao Equation, isothermal equation and Panhandle equation. The results show that the calculated results by the modified Cheng-Hao Equation, is very near to that of Panhandle equation. The new modified Cheng-Hao Equation has no limits on pipeline specifications, gas system, and pressure drops range. The scope of application of the modified Cheng-Hao Equation is larger than that of most empirical equations at present. The modified Cheng-Hao Equation can be used to calculate the pipe pressure drop for real gas flow at high pressure.