Numerical Simulation Study On Thermal Stress And Flow In A New Type Of Liquefied Natural Gas Throttle Valve In Pipeline

Due to the continuously increasing demand for LNG, the LNG valve are also risingsharply. Currently, the research of LNG valve belong to the research of the cryogenic valves.So the research of LNG valve was also mainly study on the cryogenic valves material andthermal stress, the research on LNG cryogenic throttle valve was rarely. In this paper, a newtype of liquefied natural gas throttle valve in pipeline which based on the technology of thecryogenic valves and the design manual of throttle valve was put forward. And it answers toabnormal fluid pressure generated by the sudden vaporization of cryogenic valve fluid，flowdisturbance and eddy current damage the valve.In this paper, by using thermal analysis module to simulate liquefied natural gas throttlevalve’s temperature and by using mechanical module coupled simulation to simulate thermalstress based on ANSYS Workbench analysis platform. The distribution of the throttle’stemperature and the throttle’s thermal stress was got under the condition of constanttemperature of the throttle valve inside and outside wall and under the condition of naturalconvection with the natural environment; the path was defined in the cryogenic throttlevalve different wall thickness，and the data of temperature and thermal stress was studied indifferent path；the thermal stress simulation results comparing with similar studies waspurposed to verify the correctness and reliability of the numerical simulation research.Through the analysis of simulation results came to the conclusions: under the condition ofconstant temperature of the throttle valve inside and outside wall, the high-temperature zonewas higher proportion under certain the wall thickness; the temperature was a linearrelationship with wall thickness under the condition of natural convection with the naturalenvironment; it created a larger thermal stress under the condition of constant temperature ofthe throttle valve inside and outside wall; it produced less thermal stress under the conditionof natural convection with the natural environment; the method of Insulation of cryogenicvalves setting is proposed.The numerical simulation of throttle’s flow field was carried out by Fluent software. Itverified that the throttle can meet the design conditions: got the pressure drop, flowcoefficient and flow resistance coefficient curve under the throttle different spool stroke; andthe flow characteristic curve comparing with similar studies was purposed to verify thecorrectness and reliability of the numerical simulation research. Meanwhile, the numericalsimulations of the orifice of the porous is carried out. After porous throttling, flow recoverysmooth required pipeline length decrease, the number of swirl increases, the vortex becomelittle. This paper provided a new cryogenic valve design ideas and a solution to solvecryogenic valves thermal stress damage. The porous plate throttle is applied to the throttlevalve. This is a new attempt for the design of the throttle valve. This new attemption can wellmeet the design requirements of the throttle; it answers to abnormal fluid pressure generatedby the sudden vaporization of cryogenic valve fluid, flow disturbance and eddy currentdamage the valve; it reduces the impact to the valve by several times with step-down;porous makes the vortex breakdown.