OPTIMISATION OF WASTE HEAT RECOVERY SYSTEM OPERATING PARAMETERS FORDIESEL ENGINE BASED ON RANKINE CYCLE

International audienceThis article presents an optimization study of the Rankine cycle operating parameters as a function of dieselengine operating mode. The Rankine cycle here is studied as a waste heat recovery system which uses the engineexhaust gases as a heat source. The engine exhaust gases parameters (temperature, mass flow rate and composition)were defined on the engine test bed at constant engine speed and variable load. It was found that the exhaust gasestemperature is within the range of 167°C to 557°C and the mass flow rate varies from 88,5kg/h to 281,3kg/h. An enginespeed of 2000 rpm was chosen in this study due to the fact that this speed provides higher engine thermal efficiency. TheRankine cycle thermal power and efficiency was numerically estimated by means of a simulation code in Python(x,y).This code includes discretized heat exchanger model and simplified model of the pump and the expander based on theirisentropic efficiency. The Rankine cycle working fluid mass flow rate was varied within the range of 1g/s to 10g/s andthe working pressure was within the range of 5bars to 25 bars. The numerical results revealed that the cycle thermalpower increases slightly as a function of engine load. Thus, the optimal operating parameters of the Rankine cycledepend on the heat source