有机朗肯循环封闭式膨胀机内置发电机排气冷却问题研究

Internal Generator Exhaust Cooling for Hermetic Expanders in Organic Rankine Cycles

采用全密封、内置发电机的封闭式膨胀机是有机朗肯循环重要的发展方向,利用膨胀机排气来冷却发电机是一种简单易行的技术路线。但有机朗肯循环中膨胀机排气温度相对较高,对发电机的冷却效果需要专门研究。根据集总参数思想建立了发电机等效热路模型,研究不同工况下发电机定子绕组最高温度和温升的变化规律。结果表明:在一定的冷凝温度下,随着蒸发温度的增加,定子绕组最高温度及温升均增加,分别可达151℃和85℃;而在一定的蒸发温度下,随着冷凝温度的提高,上述参数呈现下降的趋势,在冷凝温度为30℃时,最高温度和温升分别可达126℃和65℃。

Utilizing reliable and hermetic expander with internal generator is an important development direction of organic Rankine cycle(ORC).It is simple and feasible to use the expander exhaust to cool the generator in hermetic expander.However,the exhaust temperature of the expander in ORC system is relatively high,and the cooling effect on the generator needs to be studied specifically.In this paper,an equivalent thermal circuit model of the generator was established based on the lumped parameter concept.The variations of the highest temperature and temperature rise of the stator winding under different working conditions were revealed.Results show that the highest temperature and temperature rise of the generator increase with the improvement of evaporation temperature,reaching 151℃and 85℃,respectively.The highest temperature and temperature rise of the generator decrease with the increase of condensation temperature.If the condensation temperature is set to be 30℃,the maximum temperature and temperature rise can reach 126℃and 65℃,respectively.