Simulation Research Of Free-piston Stirling Booster Pump Based On CFD

Due to the development of various industries and the increasing of population,the demand for fresh water is also rising.However,the fresh water is not abundant in some countries or areas and some are facing the fresh water crisis.The reverse osmosis seawater desalination is an effective method to extract from seawater,but there are some problems in reverse osmosis seawater desalination engineering.For example,the large power consumption of the booster pump of energy system increases the cost of desalination and the pump has a complex structure and produce loud noise.Therefore,the dissertation proposes new booster equipment driven the Stirling engine,which has transmission chain with simple structure,the high output efficiency and better energy adaptability.And the dissertation using Fluent analyses and researches new booster pump structure from four aspects:(1)Based on the principle of booster pump,the dissertation designing the structural schematic diagram of the new booster pump.The new structure uses the βtype free piston Stirling engine coupled with the reciprocating pump and obtains return energy by the accumulator is compressed.And the structure has passed the feasibility test;(2)According to the initial rated power,the dissertation calculates the Stirling engine structure size,such as the size parameter of the heater,regenerator,cooler,valve piston and power piston.The dissertation also simulates the Stirling engine using Fluent by Dynamic grid technology and UDF function and obtains the Stirling engine internal field distribution,state parameter changes,power and efficiency;(3)The output system mathematical model is built.The dissertation utilizes VOF model of Fluent for simulation calculation and obtains the pressure field distribution in the pump cavity and the accumulator during the suction and drainage process,the gas velocity field distribution in the accumulator,and changes in flow and velocity of the drain.The results demonstrate parameters achieve expected requirements;(4)The parameters of the new booster pump are optimized.The dissertation researches the influencing factors on power and efficiency of the Stirling engine,including gas working medium,heat source temperature,average pressure,piston movement frequency and piston phase angle,and studies the influence of porosity and wire mesh diameter in regenerator on heat conduction loss 、 regenerative loss and pressure drop.