Quantitative study on orifice leakage flow coefficient of urban gas pipeline
The flow coefficient,a vital parameter,affects the accuracy of leakage rate calculation.To solve the current issue of the deviation between the calculation results of the hole leakage model and the actual leakage rate,which is caused by empirical value taking of flow coefficient,a small orifice gas-phase leakage experiment platform based on geometric similarity criterion was set up for the researching experiment,the theoretical calculation model and CFD simulation were also integrated to find out the reason for the above deviation at the same time.In addition,by using the 1stOpt data processing software,the quantitative flow coefficient calculation model of round and rectangle orifice was obtained through the fitting analysis of experimental data.The results show that,in the experimental test,the flow coefficient of the small orifice is mainly affected by its shape and the leakage pressure.The leakage rate of a rectangle orifice is higher than that of a circular one under the same leakage pressure and area.The theoretical calculation model ignores the influence of related factors on the flow coefficient and regards the flow coefficient as a fixed value,which is an inherent cause of the deviation.Finally,the flow coefficient calculation equation of round and rectangle orifice was obtained by multivariate nonlinear curve fitting,the fitting degree(r)both can reach 0.993,which effectively corrects the theoretical calculation model of small orifice leakage to reckon leakage rate more accurately.Meanwhile,it is found that,under a certain pressure range,the flow coefficient of the round and rectangle orifice increases with the increase of the geometric characteristic parameters(such as the diameter of the round orifice and the aspect ratio of the rectangle orifice),and finally tends to a fixed value,the flow coefficient of the round orifice is approximately equal to 0.75,and that of the rectangle orifice is approximately equal to 0.80.This result would provide theoretical support for diffusion and risk assessment after gas leakage.
public safetygas pipelinesmall hole Leakageflow coefficientquantitative researchnumerical simulation
万方数据
维普
