Ship Main Engine System Thermal Performance Calculation And Analysis Of Energy Consumption

With the global energy crisis,environmental pollution and the increase of fuel costs,the energy saving work on ship becomes the most concern issue.The accuracy of the diesel model affects the energy distribution of the main engine system directly.Establishing an accurate model of the diesel engine and calculating the energy distribution of the main engine system can provide a scientific basis for the propose of effective energy-saving measures.Based on the average model,the Seiliger cycle and the valve-timing diagram,refine the cylinder process and establish the mathematical model on the thermal performance of main engine system.Takes 5S60MC-C8,6S42MC7,6S50MC-C8,6S60MC-C7,6S70MC6 and7S60MC6 as the research objects and analyze the variation of key performance parameters with load,cylinder diameter and the number of cylinders.According to the thermal performance mathematical model,establish a energy distribution system mathematical model to calculate the output power,cooling losses,exhaust losses and other energy losses on different engines,analyze the energy consumption and the variation of each part with the changing of working conditions comparatively.Then make the larger part of energy consumption clearly,and adopt the related energy-saving measures.Compared the calculation results of the six types engines with the design data show that the calculation errors of thermodynamic parameters are less than 5%,verifying the accuracy of the model.Main engine system energy distribution calculation results show that effective power conditions account for 43.99%,exhaust losses account for 40.31%,cylinder cooling losses account for 9.37%,mechanical losses account for 4.89%,and the remaining 1.44% as other losses in 100% load in 6S42MC7 engine;there are differences on the energy consumption in different main engine system,but the main energy losses are exhaust losses and cooling losses.The heat recovery results of 6S42MC7 main engine system show that the air recovers 1.22%,exhaust boiler recovers 4.83%,water distillation equipment recovers5.06%,and the main engine system efficiency is improved by 11.11%.There are differences in different conditions about the three recovery measures.The heat air recovered is less than1%,and increases with the increase of the engine load;the heat water distillation equipment recovered is between 5% to 8%,and decreases with the increase of the engine load;theexhaust boiler recovers between 5% to 12%,and decreases with the increase of the engine load.So the application of water distillation equipment and the exhaust boiler affect the efficiency of the main engine system apparently.To make the calculation and analysis of the thermal performance and energy distribution of the ship main engine system accurately can provide a theoretical basis for the main engine system to improve the system efficiency,reduce energy losses and propose ships energy-saving measures,it has great significance to energy research of ship main engine system.