超临界二氧化碳轴流透平冷却系统流量和温度的影响研究  

Investigation on the Effects of Flow Rate and Temperature of Cooling System on SCO_(2)Axial Turbine

作　　者：唐国庆 但光局 霍文浩 孙冬婷 文俊 Guo-qing Tang;Guang-ju Dan;Wen-hao Huo;Dong-ting Sun;Jun Wen(Chongqing Jiangjin Shipbuilding Industry Co.,Ltd.;Key Laboratory of Marine Turbocharger Research,Chongqing Industry and Information Technology;National Engineering Research Center of Special Equipment and Power System for Ship and Marine;Northwestern Polytechnical University)

机构地区：[1]重庆江增船舶重工有限公司 [2]船用涡轮增压器研发重庆市工业和信息化重点实验室 [3]船舶与海洋工程特种装备和动力系统国家工程研究中心 [4]西北工业大学

出　　处：《风机技术》2024年第5期39-47,共9页Chinese Journal of Turbomachinery

基　　金：超临界CO_(2)太阳能热发电关键基础问题研究(2018YFB1501004)。

摘　　要：超临界二氧化碳(Supercritical Carbon Dioxide,SCO_(2))轴流透平引入外部低温SCO_(2)作为冷却系统冷却气,对干气密封和转子系统进行冷却,确保干气密封运行温度在200℃以内。针对某小功率SCO_(2)轴流透平冷却系统建立了包括冷却流体域、主流流体域和固体域耦合的整机计算模型,对比分析了不同冷却气流量和温度对干气密封和转子系统的冷却效果和透平效率的影响,在此基础上开展了耦合温度场和压力场的透平整机强度计算。结果表明:引入外部低温SCO_(2)能有效冷却干气密封在内的整个转子系统;随着冷却气流量的增加,透平效率和转子系统温度逐渐降低,冷却气流量越小,相同冷却气流量变化引起的效率和温度的变化越大;随着冷却气温度的增加,透平效率基本不变,转子系统温度成线性增加。当冷却气温度为120℃,流量为0.04kg/s时,透平转子系统冷却效果可满足要求,此时干气密封工作温度为194℃。强度评估结果表明:透平整机转子部件最大等效应力536MPa,位于涡轮叶片根部,各零部件应力均小于材料屈服强度,安全裕度最小为1.57,满足长期安全可靠运行需求。The cooling system was designed in a supercritical carbon dioxide axial turbine to control the operating temperature of the dry gas seal below 200℃for safe operation,that the turbine dry gas seal,rotor and casing were cooled by the low temperature SCO_(2)extracted from the pipe downstream the compressor.A coupled computational model was established for the cooling system of a low-power SCO_(2)axial turbine,including the cooling fluid domain,mainstream fluid domain,and solid domain.The influence of different dry gas seal cooling flow rates and temperatures on cooling effectiveness and turbine efficiency were compared and analyzed.Based on this,coupled temperature field and pressure field calculations were carried out to evaluate the strength of entire turbine.The results showed that the external low-temperature SCO_(2)can effectively cools the entire rotor system.As the cooling flow rate increases,turbine efficiency and rotor system temperature decrease gradually.The smaller cooling flow rate leads to the greater efficiency and temperature variations caused by the same change in cooling flow rate.As the cooling gas temperature increases,the turbine efficiency remains relatively stable,while the rotor system temperature linearly increases.When the cooling gas temperature is 120℃and the flow rate is 0.04kg/s,the turbine rotor system can meet the requirements,the working temperature of the dry gas seal is 194℃.The strength evaluation results indicated that the maximum equivalent stress of turbine was 536MPa,located at the root of the turbine blade.The stress in each component was below the material's yield strength,with a minimum safety margin of 1.57,satisfying the long-term safe.

关 键 词：超临界二氧化碳 轴流透平 冷却系统 传热特性 温度分布 

分 类 号：TB653[一般工业技术—制冷工程]