柴油机废热驱动有机朗肯循环的理论和试验

Theoretical and Experimental Analysis of an Organic Rankine Cycle Driven by Waste Heat from Diesel Engines

对柴油机废热驱动有机朗肯循环(ORC)发电系统的4种方案进行了理论分析;并以200,kW柴油发电机废热回收为对象,设计一台以R245fa为循环工质的废热驱动ORC发电系统样机.在柴油发电机输出功率为180,kW时,分别以"发动机冷却液"和"发动机冷却液和尾气"为热源,测试ORC系统的循环性能.结果表明:单独依靠发动机冷却液驱动ORC系统时,节温器开闭导致系统无法稳定工作.当强制开启节温器、R245fa流量从0.32,kg/s增大到0.41,kg/s时,冷却液出水温度迅速下降,而系统净发电量单调递增至3.1,kW;净效率曲线呈先增后减的变化趋势,并在0.35,kg/s时达到3.8%的最大值.当发动机冷却液和尾气共同驱动ORC系统时,系统净发电量可达9.9,kW,净效率为6.3%.

Four power generation schemes using waste heat from diesel engines with organic Rankine cycle(ORC)systems were theoretically analysed. Aiming at recovering waste heat of a 200,kW diesel engine,a prototype of ORC power generation system was developed,with R245fa as the working fluid. Cyclic performance of the ORC system was tested,driven separately by engine coolant and coolant plus exhaust gas. Experiments results show that,when only driven by engine coolant,the performance of the ORC system is unstable owing to the opening and closing of the thermostat. If the thermostat is forced to open,with flow rate of R245fa increasing from 0.32,kg/s to 0.41,kg/s,engine coolant temperature is decreased,and net power output is increased to 3.1,kW. Net efficiency of the system reaches its maximum value of 3.8% at 0.35,kg/s. When driven by coolant plus exhaust gas,net power output of the system reaches 9.9,kW and net efficiency is 6.3%.