变工况下车用柴油机排气余热有机朗肯循环回收系统

摘要

An organic Rankine cycle system with recuperator was designed for recycling waste heat of a vehicle diesel engine and R245fa was used as working medium. The change of waste heat from vehicle diesel engine under variable working conditions was studied. The operating performance of the organic Rankine cycle system with recuperator was analyzed under variable working conditions and the influence of degree of superheat on the organic Rankine cycle system with recuperator was discussed. Three evaluation indices, waste heat recovery efficiency (WHRE), engine thermal efficiency increasing ratio (ETEIR) and output energy density of working fluid (OEDWF) were presented for the vehicle diesel engine-organic Rankine cycle combined system. The net power output, WHRE and ETEIR could reach maximum values of 43.74 kW, 14.93%and 13.58%.%为回收车用柴油机的排气余热设计了一套带回热器有机朗肯循环系统，采用纯工质R245fa作为工作介质。通过实验研究了车用柴油机变工况下排气余热的变化规律，分析了不同工况下带回热器有机朗肯循环系统的运行性能，讨论了过热度对带回热器有机朗肯循环系统运行性能的影响。针对车用柴油机-有机朗肯循环联合系统提出了余热回收效率、发动机热效率提升率、单位工质输出能量密度3个评价指标。研究表明，带回热器有机朗肯循环系统的净输出功率、余热回收效率、发动机热效率提升率最大分别可以达到43.74 kW、14.93%、13.58%。