CAJ | 학술논문

目前针对有机朗肯循环（ORC）系统小型涡轮在变工况下运行性能的研究很少，对运行性能随涡轮转速的变化机制缺乏了解。而在可再生能源及余热利用过程中，ORC系统小型涡轮常处于变转速工况。把实验数据和设计数据相结合，针对采用R123为工质的小型径-轴流式高转速涡轮，采用CFX软件对涡轮叶轮三维流场进行了数值模拟。给出了热效率和叶轮等熵效率随转速的变化趋势，指出余速损失是低转速下热效率降低的主要原因。提出了修正后的涡轮能量公式，在低转速工况下对涡轮的做功性能分析时不能忽略涡轮进出口的动能变化，在计算涡轮出口的余速损失时，必须考虑工质流动速度的方向特性。
목전침대유궤랑긍순배（ORC）계통소형와륜재변공황하운행성능적연구흔소，대운행성능수와륜전속적변화궤제결핍료해。이재가재생능원급여열이용과정중，ORC계통소형와륜상처우변전속공황。파실험수거화설계수거상결합，침대채용R123위공질적소형경-축류식고전속와륜，채용CFX연건대와륜협륜삼유류장진행료수치모의。급출료열효솔화협륜등적효솔수전속적변화추세，지출여속손실시저전속하열효솔강저적주요원인。제출료수정후적와륜능량공식，재저전속공황하대와륜적주공성능분석시불능홀략와륜진출구적동능변화，재계산와륜출구적여속손실시，필수고필공질류동속도적방향특성。
Few studies have focused on the overall performance and internal flow field of small-scale turbine under off-design conditions in an organic Rankine cycle (ORC) system. The small-scale turbine of an ORC system is often used at variable rotation rates for renewable energy and waste heat utilization. The 3D flow field of a small-scale, radial-axial flow turbine impeller is simulated with CFX software and verified by experimental data and design data, which uses R123 as work fluid. The variations of thermal efficiency and isentropic efficiency of impeller with the rotating rate are provided. The leaving-velocity loss of the turbine is the main cause of lower thermal efficiency at a low rotation rate. A revised equation for calculating the power output of a small-scale turbine under the off-design condition, which considers the change in the kinetic energy between the inlet and outlet of the turbine, is also proposed. The flow direction of working fluid should be considered when calculating the leaving-velocity loss at the outlet of the turbine. The isentropic efficiency of the turbine is evidently low at less than 20000 r·min-1, whereas the kinetic energy difference between the inlet and outlet of the turbine impeller is close to 0 at 60000 r·min-1.