Abstract: The current efficiency of the organic Rankine cycle (ORC) is generally low.The performance of the expander has a direct impact on the cycle efficiency. In order to enhance the scroll expander performance of organic Rankine cycle,the scroll expander was improved. The movable scroll wraps do not block the inlet hole,the inlet and outlet are distributed symmetrically,and the scroll profile modification is adopted. The influence of inlet pressure,flow rate and rotating speed of the scroll expander on its performance was studied. The experimental results showed that the maximum external isentropic efficiency of the modified scroll expander would be up to 53%,and there is an optimal pressure value,which makes the maximum external isentropic efficiency of the expander. The increase of the inlet flow rate will increase the rotating speed and the output power of the expander. The changes of isentropic efficiency show parabolic curves,and different loads correspond to different optimal flow values,which makes the maximum external isentropic efficiency of the expander. Different loads of the expander have different optimal speeds,making the maximum output power,the optimal speed is larger as the inlet pressure increases. Research results showed that it is feasible to improve the scroll expander,and the experiments of expander point out the direction for further improvement.

Key words: organic Rankine cycle(ORC), scroll expander, isentropic efficiency, performance experiment

摘要： 目前有机朗肯循环（ORC）的效率普遍较低，而膨胀机的性能将对循环效率产生直接的影响。为提高有机朗肯循环用涡旋膨胀机的性能，本文提出对涡旋膨胀机进行了改进，使动涡旋齿的齿头不会遮挡进气孔，进、出气口对称分布，并对涡旋齿端型线进行了修正。研究改进后涡旋膨胀机进口压力、流量、转速等参数对其性能的影响。实验结果表明：改进后膨胀机的最大外等熵效率为53%，且存在一个最佳压力值，使得膨胀机的外等熵效率最大。进口流量的增加会使膨胀机的转速提高，输出功率增大。膨胀机的外等熵效率变化曲线呈抛物线变化，不同的负载对应着不同的最佳流量值，使得膨胀机的外等熵效率最大。不同负载下的膨胀机有着不同的最佳转速，使得其输出功最大，且进气压力越大，其最佳转速也越大。研究结果表明：对涡旋膨胀机的改进是切实可行的，且对膨胀机的实验为以后进一步改进指明了方向。

关键词: 有机朗肯循环, 涡旋膨胀机, 等熵效率, 性能实验