Selection of supercharging system for high-speed marine diesel engine
The article presents the results of the study of pulse and Isobaric exhaust systems of a piston engine depending on the average effective pressure. The purpose of this work is to identify the effective use of a pulsed or isobaric exhaust system from the point of view of the loss of working capacity of exhaust gases during the movement of the energy flow from cylinders to the turbine when forcing the piston engine according to the average effective pressure. Existing supercharging systems do not have a clear area of use depending on the average effective pressure. Until now, in practice, in the process of creating more forced diesel engines, designers are forced to select many elements of exhaust systems on the basis of previously acquired experience in the operation of previous designs. The reason lies in the lack of understanding of the physical essence of the processes of local losses of the working capacity working fluid, for example, during the movement of gases from the engine cylinders to the turbine. In the work are obtained new results of calculations of impulse and isobaric exhaust systems of Caterpillar 3508C engine depending on the level of forcing on the average effective pressure with the use of the characteristics method, the quasi-stationary method and the exergy method are obtained. A comprehensive approach to solving the problem of choosing the optimal exhaust system when forcing the piston engine according to the average effective pressure is developed. To solve the goal of the study, a modern approach to assessing the efficiency of various supercharging systems - exergy method -was applied. The obtained results confirm the possibility of using the exergy method to assess the efficiency of exhaust systems from the point of view of the losses of working capacity of exhaust gases. The selected optimum system of exhaust system of the Caterpillar 3508C engine in terms of the losses of working capacity of exhaust gases depending on the average effective pressure.