Flow coefficient correction of gas pipeline based on small hole model
As an uncertainty in the calculation of pipeline leakage rate,flow coefficient is haphazardly selected at present.To solve this problem,based on the theoretical analysis of the small-hole model,combined with the subscale test and CFD numerical simulation,the influences of internal pressure of the pipeline,leakage port shape,leakage area and roughness of the pipe wall on the leakage rate and flow coefficient were investigated.The flow field near the leakage port was analyzed by the velocity vector and Mach number,with the flow coefficient returned by multivariate nonlinear fitting method.The results show that the theoretical values under different conditions are higher than the simulated and experimental values,and there is good agreement between the experimental and simulated values.Under the same pressure,and with different leakage port shapes,the leakage rate is linearly correlated with the leakage area.Under the same pressure and with the same leakage area,the rectangle port shows the largest leakage rate,and the circle port the smallest,which indicates that the rectangular leakage port has the largest flow coefficient,followed by triangle and circle ports.The correlation coefficients of the modified flow coefficient equation reach up to 0.995 1,0.996 4 and 0.992 5 respectively,which can be used to calculate the leakage rate under different working conditions.
万方数据
维普
