The Research On The Model And The Performance Of The Matching Between Diesel Engine And Marine Waste Heat Recovery System

Nowadays,with the growing shortage of global energy,the over rising of fuel price and the gradual deterioration of ecological environment,countries around the world are actively looking for a variety of advancedtechnologies and solutions for energy-saving and emission-reduction,so as to improve the energyutilization and ensure the energy supply.For the sake of less pollution and the latest EEDI(energy efficiency design index)revised by the International Maritime Organization,researchers should explore effective countermeasures to actualize sufficient and reasonable utilization of waste heat,in order to ameliorate the heat utilization efficiency and achieve the energy conservation significantly.In addition,since the thermal efficiency of the diesel engine is increasing,the exhaust temperature is decreased year by year,which means that it will certainly impose some constraint on the matching characteristic of the whole waste heat utilization system.In this paper,the main works are presented as follows:(1)Diesel engine modeling by using GT-Power software.Some simulations are carried out based on the available data for 8S60 ME diesel engine under different working conditions and then the in-cylinder pressure curve,the combustion curve and the temperature curve are gained.Moreover,processing scheme with exhaust bypass,which increases the delivery temperature and energy efficiency,are applicated.Emission performance of exhaust gas is tested.Relevant conclusions show that tail gas quality meets the environment requirements.(2)The GT-Power software cannot well simulate the operation processof heat recovery steam generator;therefore,the average-value model of the marine model needs to be established by MATLAB/Simulink for further researching the response of waste heater boiler to the operation of diesel engine.Then the static data of average-value model is verified by the aforementionedGT-Power model data.(3)On the basis of detailed description ofwaste heater boiler’s structure,classification,characteristics,modeling methods as well as model features,each sub-module of marine waste heater boiler is investigated by means of modular modeling method and lumped parameter modeling method.Then models are simplified with the comprehensive consideration of material exchange,energy exchange and thermodynamic factors.(4)Simulation model of diesel engine waste heat utilization system is set up by directly connecting the diesel engine and waste heat boiler in MATLAB/Simulinksoftware.Then steady state characteristics and dynamic performance of marine waste heat boiler are analyzed.It can be seen that the exhaust heat utilization system is in good condition after the diesel exhaust temperature is raised.When the speed of diesel engine suddenly increases,the circulating water supply should be expanded subsequently to improve steam-water circulation radio.Instead,it should be decreased accordingly to reduce the accident frequency and then realize the simulation and verification ofthe marine waste heat utilization system.