Simulation And Optimization Of Marine Main Diesel Engine With Waste Heat Recovery By Engine Tuning

With the International Maritime Organization(IMO)referring Energy Efficiency Design Index(EEDI)as an index of checking ship operation energy consumption level,as well as constantly rising fuel price,waste heat utilization technology of two-stroke diesel engine with high power has become a research hotspot in the field of ship.The key to to improve the energy utilization efficiency of the entire system and to grasp the standard engine modulation method is to match characteristics of the standard engine,waste heat boilers and turbines.Firstly,based on the detailed analysis on the main structure of the 6S50ME-C8.2 diesel engine and specific characteristics of the low-speed two-stroke diesel engine,a simulation model was established by GT-Power.According to the propulsion characteristic,the model was verified and the simulation results are compared to the experiment data.Comparison results verified the accuracy of the simulation model due to the consistent between simulation results and the experiment data.Secondly,according to the experimental data of 6S50ME-C8.2 diesel engine cylinder pressure,the author analyzed the characteristics of heat release rate.On this basis,the author established a working process simulation model of the whole engine with engine working process of special simulation software GT-Power,and the engine propulsion property verification calculation.The results showed that,whether in the rated load or part of the load,the simulation results and the experimental data were consistent,which verified the accuracy of the simulation model.Based on the computer simulation model,boundary conditions were simplified and power turbine simulation model on WHR engine,established the simulation model of diesel engine,by adjusting the timing and turbocharger host modulation calculation,analysis of the timing of engine,turbocharger adjust,influence on engine performance,and the WHR engine was optimized.Based on the optimized WHR engine matching the power turbine waste heat recovery system and the WHR system was optimized.Finally,the author analyzed the standard engine emission and thermal balance.The results showed that,WHR system's NOx emission slightly increased compared with the standard load.WHR engine's fuel consumption rate increased slightly compared with standard engine.But the whole system energy utilization rate was more than 50%,and in operating conditions,the rate rose from 48.2%to 52.5%,and the risen of the energy utilization rate also mean that the entire ship waste heat utilization system fuel consumption rate decreased.Fuel consumption reduction also made the ship operating costs reduced in the operation process.