| Gas pressure regulator is a vital part in the town gas transmission and distribution network as it plays important roles of pressure regulation,pressure stabilization and safety cutout,etc.Based on the investigation and the evaluation of the gas pressure regulator of Chengdu Jiesen Transmission and Distribution Equipment Co.,Ltd,it is found that there were certain deficiencies in the pressure regulating performance of RTZ-50/0.4FQ gas pressure regulator which is independently researched and developed by the company.However,this type of gas pressure regulator is widely used in gas regulating of buildings,small boilers and public service equipment.If the gas regulating performance is poor,it may lead to as minor as damages of gas appliances and as major as fire,explosion,personal casualty and economic loss.Therefore,the paper conducts a gas regulating feature test on this type of gas pressure regulator.It analyses the deficiencies in pressure regulating performance of the gas pressure regulator and does numerical modeling on the regulator with various structure parameters by simulation software Fluent based on CFD.The paper also analyzes the influence laws of structure parameters on pressure regulating features and inner flow field,which provides guidance for the optimization of structures and performance of the gas pressure regulator.In the end,the paper puts forward optimization schemes for this type of gas pressure regulator based on the numerical simulation results and verifies the optimization schemes through the numerical simulation.In general,the paper does the following researches:(1)It does gas regulating feature test on the working condition of RZT-50/0.4FQ gas pressure regulator with outlet pressure of 5-8kPa by combining the research status.The static characteristics curves of the regulator are drawn under different inlet pressures based on the test results.Through the analysis of the static characteristic,the shortcomings of this type gas pressure regulator are as follows:1)although both the accuracy class and lock-up pressure class of the regulator meet requirements of Ac=10 and Sg=10,the fluctuations of outlet pressure generated over flows and input pressure are as large as 1000Pa and 650Pa.These values are larger than those of gas pressure regulators with better pressure regulating performance.This is to say that the gas regulating performance of this type of regulator needs further improved.2)The placement mode and position of the signal pipes of this type of regulator are undefined,so the length and position of the signal pipes needs adjusted repeatedly during production,which enhances production difficulty and reduces production efficiency.(2)A numerical simulation method applicable to the researched type of gas pressure regulator is put forward.It also does force analysis of its valve disk and establishes valve disk force mathematical model by combining with the structure characters of the gas pressure regulator.Firstly,the 3D modelings of the regulator in various working conditions are built with the Solidworks-3D modeling software;then the numerical simulations on the regulator in various working conditions are carried on with the Fluent software and the actual operating condition points of the regulator are identified based on the valve disk force mathematical model during the simulation process.At last,the numerical simulations on some working conditions in the test are carried out with the numerical simulation methods and valve disk force mathematical model,and so does the error analysis.And the maximum error of the outlet pressure is 4.28%,which comes within the acceptable range and verifies the applicability and accuracy of the simulation method and valve disk force mathematical model.(3)Based on the valve disk force mathematical model,the numerical simulations of the regulator are carried out with different structure parameters(pressure measurement method,spring stiffness,valve disk diameter)to analyze the influence laws of different structure parameters on pressure regulating features and inner flow field.In the end,some suggestions on structure and performance optimization of the regulator are put forward based on the analysis results.(4)Some optimization schemes are put forward for the researched type of gas pressure regulator based on the research results:1)The optimization scheme of valve disk structure fillet:it decreases the vortex area surrounding the regulator valve port and the area of negative pressure areas.The maximum flow velocity decreases from 355.1m/s to 307.43m/s and the minimum negative pressure rises from-49.35kPa to-26.33kPa.And the inner flow field becomes more stable.2)The optimization scheme of increasing diaphragm diameters:the optimization results shows that the accuracy class of regulator becomes Ac=6.32 from Ac=10.It realizes the optimization of the regulator performance as the accuracy class is enhanced.3)The optimization scheme of reducing valve disk diameters:the optimization results shows that the accuracy class of regulator raises to Ac=8.86 from Ac=10 after optimization.It realized the optimization of the regulator performance.4)The optimization schemes are compared with the optimization objective of accuracy class.Final,it is recommended to optimize the regulator performance by the optimization scheme of increasing diaphragm diameters.5)The channel optimization shceme is put forward aiming at rapid drop of outlet pressure over flow under condition of inlet pressure of 0.1 MPa:the channel is designed as expanding and contracted pipe with 5° of taper.After optimization,the fluctuation of outlet pressure within working flow range decreases from 1000Pa to 812.52Pa,which decreases the influence of flow on outlet pressure and enhances the pressure regulating performance of the gas pressure regulator.At the same time,this paper put forward a suggestion for the placement of the signal pipes of this type of regulator. |
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