Turbo-compound Diesel Engine Thermodynamic Analysis And Performance Simulation

With the continuous development of turbocharger technology for the diesel engine,turbine output power is increasing to drive the compressor air and other components, sodifferent forms of composite diesel engine were come into being. In this article, a combustionchamber was introducted to the diesle engine turbocharging system in order to furtherimprove the power, improve the temperature of turbine intake air.Adopt thermal efficiency and exergy efficiency as an indicators,evaluate the thecomposite diesel engine thermodynamic cycle analysis. Analyze thermal efficiency andexergy efficiency of mixed heating cycle and Brayton cycle analysis; actual combination ofcomposite diesel engine air flow first shunt remixed characteristics, the introduction of theconcept of air flow volume fraction, the cylinder working process and secondary combustionchamber thermodynamic processes combined into a changing process, derived polytropicindex and volume fraction, constant pressure pre-expansion ratio, constant volume boosterthan warming ratio, pressure ratio and other parameters of the polytropic index The influencelaw; polytropic index of composite diesel engine investigated; draw turbo compound dieselengine pv complete the the composite diesel engine thermodynamic analysis.Thermodynamic analysis showed that: The amount of fuel injection of engine and thecompression ratio maintain a constant, increasing the turbine inlet temperature that help toimprove the the composite diesel engine thermal efficiency, efficiency of exergy, and outputpower; volume fraction is characterized the proportion by the air flow of the engine in thetotal air flow, reduce the volume fraction, will improve the thermal efficiency of thecomposite diesel engine, exergy efficiency and output power at the same time, Constantpressure pre-expansion ratio and Constant volume pressure ratio of the diesel engine wereincrease, conducive composite diesel engine heat efficiency, efficiency and net exergy outputpower increases.Based on the GT-POWER modeling concept, modeling the turbocharged diesel engineprocess simulation. On this basis, add the combustion chamber and the injector of combustion chamber, appropriately simplify the turbocharge system, establish the turbo-compound dieselengine performance simulation model; introduce the unit mass power of air, research pressureratio, turbine inlet temperature, diesel engine compression ratio and turbine, compressor andother major components of efficiency impact on turbo-compound diesel engine power, fuelconsumption, power-turbine powerand power distribution parameters.Simulation results show that: the supercharging ratio, turbine inlet temperature and themajor component efficiency has a direct impact on the, when the turbine inlet temperature isconstant, there is the optimum supercharging ratio; enhance the turbine inlet temperature isconducive to improve the output of the power turbine and unit mass power of air, reducing thethe a turbo-compound diesel engine fuel consumption; while increasing the turbine inlettemperature can also reduce the a turbo-compound diesel engine air flow, which is conduciveto reducing the supercharger and the intake and exhaust system size; improve the enginecompression ratio is conducive to improve the composite diesel engine output power, but theimpact limited; and, the compression ratio of reduction in the proportion of the total powerconducive to enhance the power of the power turbine and power turbine power; diesel engineperformance impact strength of the main components of the efficiency of the turbo compoundsequentially turbine, compressor, and the combustion chamber.