Research On The Dynamic System Of ? Type Stirling Cycle Free Piston Reverse Osmosis Desalination

Freshwater resources are the important material foundation for survival,economic development and social progress of mankind.Nowadays,the shortage of freshwater resources is a major problem we faced,while reverse osmosis desalination is an effective way to solve the shortage of freshwater resources in coastal areas,on ships and on isolated islands.Considering the power system of reverse osmosis seawater desalination,it only needs to provide the pressure that can push the seawater through the reverse osmosis membrane by overcoming the osmotic pressure.Presently,the power input of reverse osmosis seawater desalination generally uses the high-pressure pump,which has lower final conversion efficiency and weaker energy adaptability.However,as an externally-heated piston power machine,the Stirling engine can eliminate rigid body transmission mechanisms such as crank connecting rods on the basis of traditional engines.It adopts free piston type and uses non-rigid medium as the receiver of mechanical energy in the piston translation to maintain stable output.So the Stirling engine can be used as the power input of reverse osmosis desalination system.The current research on the development of the field in reverse osmosis desalination driven by thermal energy been done,starting from reducing the energy conversion and transmission links and improving energy utilization efficiency,an ?-type Stirling-cycle free-piston power system of reverse osmosis desalination has been designed with taking full advantage of the Stirling cycle.The research content of the topic is as follows:(1)The ?-type Stirling-cycle free-piston power system of reverse osmosis desalination has been designed.In the power part of the power system,an adiabatic model of the a-type Stirling engine and a dynamic model of the piston assembly are established.The structural parameters of the Stirling engine been designed,the motion law of the Stirling engine in the power system is obtained with solving the differential equations by means of RUNGE-KUTTA method using MATLAB platform.The final result shows that The heat output of the Stirling engine was finally calculated to be16.76 KW.(2)The mathematical model of reciprocating linear pump in the ?-type Stirling-cycle free-piston reverse osmosis desalination power system has been established.The relevant structural parameters of the reciprocating linear pump beendesigned,the related motion law is obtained by simulation with MATLAB software.After calculation and analysis,it can be acquired that the final output power of the power system is 15.37 KW and the intermediate transmission efficiency is 91.8%,which indicates that the power system has a stable pressure output to ensure the smooth progress of the seawater desalination.(3)The model of each module of the power system and the power system entire model have been established based on the ?-type Stirling-cycle free-piston reverse osmosis desalination power system.Then the entire model of AMESIM in the power system been analyzed by simulation,the volume and the flow change law of the pump,and as well as the flow and pressure change law of desalination component in the final power system output can be obtained.(4)The Stirling engine of power part in the power system has been optimized with the method of particle swarm optimization.By choosing the optimal parameters of the Stirling engine,the power output of the Stirling engine of the power system is been increased by 15.22% with optimization.