STUDY ON THE INFLUENCE OF EVAPORATOR OF ORC SYSTEM ON ENGINE PERFORMANCE

asme-orc2015 Tracking Number 39

Of the engine’s fuel combustion energy, only about one third is converted into mechanical energy and the remaining is dissipated in the form of waste heat through the exhaust and the coolant system [1]. Organic Rankine cycle (ORC) is an effective method for waste heat recovery and has been widely applied in many domains. Baik et al propose that the heat-transfer performance of the exchanger has a significant impact on the output power of the ORC [2]. Taking as the heat transfer component of ORC system, evaporator has an impact on ORC system, but also influences engine performance. In this paper, the influences of evaporator of ORC system on engine performance are studied. 3D model of the fin-and-tube evaporator of ORC system is established while CFD numerical simulation is used to obtain the distribution characteristics of the temperature field, the pressure field, and the velocity field of the exhaust in the evaporator shell side. The performance of fin-and-tube evaporator of ORC system is analyzed based on the aforementioned simulation results. Subsequently, a simulation model of the engine is developed based on GT-Power software and the back pressure of exhaust is set based on the pressure drop between import and export of evaporator which is acquired from the simulation result. Moreover, the variation of engine power, torque and brake specific fuel consumption is discussed. Results show that, equipped with the evaporator of ORC system, the engine power and torque decreased slightly while the brake specific fuel consumption increased slightly. On the whole, the influences of the evaporator of ORC system for engine performance are not especially obvious.