Modeling And Simulation Of Marine Air Conditioning Refrigeration System

With the improvement of functional requirements of marine engine simulator,the functions and operation of various marine equipment in the simulator need to be improved and enhanced.Air conditioning and refrigeration system is one of the main auxiliary systems of the ship,and it is an essential shipping equipment in modern ship construction.The operation of the system has a direct impact on the personnel and key equipment on board.Therefore,the modeling and Simulation of ship air conditioning system is of great significance.In this thesis,the air conditioning and refrigeration system of Dalian Maritime University practice teaching ship is selected as the research object,the general situation and operation characteristics of the ship air conditioning and refrigeration system are introduced in detail,and the principle of conservation of mass and energy,thermodynamics,heat-transfer mechanism,hydrodynamics and other related theories are applied to analyze the mechanism.On the premise of certain simplification,the mathematical modeling of the main components of the marine air conditioning and refrigeration system,such as compressor,electronic expansion valve,condenser,evaporator,air cooler and cabin temperature,is established.By using the calculation and simulation functions of Matlab/Simulink software,the components of the air conditioning system are simulated respectively,and the whole system is connected according to the coupling relationship between the main components of the ship’s air conditioning and refrigeration system.According to the data collected from the real ship,the changes of the system parameters under the corresponding working conditions are verified,The simulation results show that the data obtained by the model is in a reasonable error range,and has a certain reliability,which can analyze the system operation trend and optimize the operation on the basis of the model.This thesis makes a detailed analysis of PID control,which is the most widely used superheat degree control method in ships.Aiming at some weaknesses in PID control,it optimizes and integrates PID parameters by using the advantages of fuzzy intelligent algorithm and particle swarm optimization algorithm,and obtains new fuzzy PID control method and PID control method based on particle swarm optimization,The relationship function between the opening and superheat of the electronic expansion valve is given by using the simulation model.The conventional PID and fuzzy PID control models are built in Simulink,and the particle swarm optimization algorithm is written in Matlab to optimize the conventional PID.The results show that the PID controller optimized by fuzzy algorithm and the PID controller based on particle swarm optimization have the advantages of small overshoot and short adjustment time.Finally,based on the simulation model of ship air conditioning and refrigeration system,the paper designs and develops the simulator of ship air conditioning system.Based on Visual Studio platform,WPF graphics technology is used to design and manufacture the relevant controls and operation interfaces in the air conditioning system of ships,and the underlying model class is developed by using C# language.The developed air conditioning system has friendly interface,clear operation flow,strong logic and accuracy,and has been deployed on our university server platform,which can download and operate online to meet the needs of trainees training and mathematical analysis of researchers.