朗肯循环耦合双效溴化锂吸收式制冷系统建模及性能分析
刘坚,谭先琳*,毕成,梁梓原,付宇乐,曾杨,杨远志
广西大学机械工程学院,广西 南宁 530004
摘要:为提高船用柴油机余热回收效率,利用MATLAB对朗肯循环及双效溴化锂吸收式制冷系统进行建模及热力学分析,确定朗肯循环热效率的影响因素及双效溴化锂吸收式制冷阶段中废气温度、高压发生器温度、低压发生器温度对制冷量和性能系数的影响。结果表明:朗肯循环最佳工质为水;升高初温、初压和降低背压可提高朗肯循环热效率;随着废气温度增加,双效溴化锂吸收式制冷系统的制冷量增加,制冷性能因数降低;随着高压发生器温度升高,制冷量降低,制冷性能因数降低;随着低压发生器温度降低,制冷量增加,制冷性能因数降低;应根据不同环境及场合要求,调整双效溴化锂吸收式制冷系统相关参数。
关键词:朗肯循环;双效溴化锂吸收式制冷;余热回收;MATLAB建模
Modeling and performance analysis of Rankine cycle coupleddouble-effect lithium bromide absorption refrigeration
LIU Jian, TAN Xianlin*, BI Cheng, LIANG Ziyuan, FU Yule,
ZENG Yang, YANG Yuanzhi
School of Mechanical Engineering, Guangxi University, Nanning 530004, China
Abstract:In order to improve the efficiency of waste heat recovery in marine diesel engines, MATLAB is used to model and thermal dynamically analyze the Rankine cycle and dual effect lithium bromide absorption refrigeration system. The factors affecting the thermal efficiency of the Rankine cycle and the effects of exhaust gas temperature, high-pressure generator temperature, and low-pressure generator temperature on the refrigeration capacity and performance coefficient during the dual effect lithium bromide absorption refrigeration stage are determined. The results indicate that the optimal working fluid for the Rankine cycle is water. Raising the initial temperature, the initial pressure and reducing back pressure can improve the thermal efficiency of the Rankine cycle. As the exhaust gas temperature increases, the refrigeration capacity of the dual effect lithium bromide absorption refrigeration system increases, and the refrigeration performance coefficient decreases. As the temperature of the high-pressure generator increases, the cooling capacity decreases and the coefficient of refrigeration performance decreases. As the temperature of the low-pressure generator decreases, the cooling capacity increases and the refrigeration performance coefficient decreases. The relevant parameters of the dual effect lithium bromide absorption refrigeration system should be adjusted according to different environmental and occasion requirements.
Keywords:rankine cycle; double-effect lithium bromide absorption refrigeration; waste heat recovery; MATLAB modeling