Structural Analysis And Optimization Of Urban Gas Pressure Regulator Based On Thermo-Hydro-Mechanical Coupling

Due to the low ambient temperature and high hydrate content in the natural gas,during the operation of gas pressure regulator,ice blockage often occurs near its valve port,which not only reduces the efficiency of gas transportation,but also poses a great threat to the safety of gas transportation.At the same time,the internal structure of the gas regulator due to long-term high-pressure gas environment,its internal wall surface is prone to damage,reducing the reliability of the regulator.At present,the regulator ice plug and internal structure of the analysis is not deep enough,therefore,it is necessary to study the phenomenon of gas regulator ice plug and regulator internal structure of the force and deformation,analysis of ice plug and structural damage factors affecting the regulator to improve the operating conditions of the regulator method to improve the reliability of the regulator has important engineering significance.In this paper,firstly,the FL series gas regulator is used as the research object,and a fluid domain and solid domain model of the regulator were established respectively.The flow field law of the fluid domain model was analyzed,and it was found that the velocity,pressure and temperature changes in the fluid domain are in accordance with the basic laws of the regulator operation;the maximum fluctuation of the outlet pressure relative to the average deviation of the outlet pressure is 0.82%,which meets the requirement of less than 1%.Secondly,the regulator solid domain model and fluid domain model were verified for engineering,the results show that the maximum relative error between the actual outlet wall temperature and the simulated wall temperature is 8.21% and the average error is 4.69%;the maximum relative error between the actual outlet flow rate and the simulation of the outlet flow rate is 11.27% and the average error is 6.82%.The established regulator model is reliable,and the calculation results are accurate.Based on the computational fluid dynamics theory,the flow field of the regulator at different openings was simulated and the results of gas flow velocity,temperature,pressure,water phase and turbulent kinetic energy calculations at each opening were compiled and analyzed.It is found that in the case of the smaller valve opening,there is a large negative pressure zone near the valve opening,there is a significant drop in temperature,turbulent flow and a larger vortex,higher turbulent kinetic energy resulting in higher energy loss,and the water phase distribution area has a high degree of overlap with the above situation.Comparison of the regulator in the actual operation of the freezing plug location,found that the regulator valve port near that is the weakest position of the gas regulator occurred ice plug.The results show that when the opening is above 50%,the gas temperature is kept above 5 ℃,it is not easy to form ice plugging.Based on the results of the previous flow field analysis,the gas regulator structure was simulated with thermos-hydro-mechanical coupling method.Firstly,the temperature field and heat flux of the regulator are analyzed,and the results show that it is necessary to introduce the influence of temperature in the study of regulator structure problems.The regulator deformation,equivalent force and thermal strain analysis,found that the regulator in 20% of the opening,the sleeve,valve bore and the outlet valve seat wall at the stress are larger,taking into account all the factors affecting the regulator open for 20% of the working conditions model as the object of study,select the equivalent force for the optimization of the objective function,the regulator structure to optimize the design.The analysis of variance,diagnostic analysis and perturbation analysis are carried out by using Design-Expert regression analysis software,and the response surface equation with good fitting and high prediction ability,the optimal parameter combination of the optimized part of the voltage regulator and the maximum equivalent stress under the structure are obtained in combination with the response surface diagram analysis.The best parameter combination is that: the wall thickness of sleeve is 7.25 mm,the diameter of valve bore is 25 mm,and the wall thickness of outlet valve seat is 31.05 mm.The maximum equivalent stress under this parameter combination is 135.62 MPa.