Flow Characteristics And Strength Analysis Of High Parameters Pressure Reducing Valve

"Cogeneration" is a part of the national energy strategy,which is an important measure to achieve the sub-bands and efficient utilization of energy. As a core component of "cogeneration" project, pressure relief valve has been widely used in major national construction and development projects. However, the conventional valve has been unable to adapt to the high temperature and pressure, high pressure difference required by working conditons in the modern industrial production. therefore, there is an urgent need for the valve structure optimization and innovation. This paper developed a kind of high parameters angle type valve with inner and outer porous shrouded and porous orifice plates as the expansion element, and a systematic numerical simulation and analysis of its flow characteristics under high peresure difference condition and strength under high pressure and temperature condition. The main research content and results are as follows:Firstly,based on fluid analysis software FLUENT, fluid regional grids of the valve were established. The occurrence of blocking flow, flow characteristics and flow parameters changes (pressure,speed,temperature)at different pressure valve openings were studied.The critical pressure ratio, the flow characteristics curve of multistage decompression system were obtained; and illustrated the multi-stage decompression mechanism and pressure distribution under different openings; analyzed the emergence of flow vortex from flow aspect, and to verify the existence of vortex and find out the energy loss changes in accordance with opening changes from energe aspect;and analyzed the steam superheat change in accordance with the opening of the valve.Secondly,based on software ANSYS Workbench, take small flow conditions as example, transient temperature field of valve body section and key nodes are calculated with finite element method under constant steam parameters (10MPa, 520℃). Dangerous conditionsand and dangerous node of the whole process were obtained, which are the moment and position that valve body wall temperature difference reaches the maximum.Finally, based on the result of temperature field calculation, the thermal stress, mechanical stress, equivalent stress and circumferential stress were calculated in the process of steam with constant parameter into valve. Acquired the maximum stress area, and calculated fatigue loss in thee valve opening process at different valve openings with MONSON methods.The research study is of great significance to ensure the regulation performance, safe operation of high parameters valve.