应用于燃气轮机余热回收系统的超临界CO_(2)径流式透平性能探究  

Performance of Supercritical CO_(2) Radial Turbine for Gas Turbine Waste Heat Recovery System

作　　者：杨岳鸣 秦侃[3] 韩奎华[1] 徐进良[4] 齐建荟[1,2,4] YANG Yue-ming;QIN Kan;HAN Kui-hua;XU Jin-liang;QI Jian-hui(Shandong Engineering Laboratory for High-Efficiency Energy Conservation and Energy Storage Technology&Equipment,School of Energy and Power Engineering,Shandong University,Jinan 250061,China;Suzhou Institute,Shandong University,Suzhou 215123,China;School of Marine and Technology,Northwestern Polytechnical University,Xi’an 710072,China;Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization,North China Electric Power University,Beijing 102206,China)

机构地区：[1]山东大学能源与动力工程学院高效节能及储能技术与装备山东省工程实验室,山东济南250061 [2]山东大学苏州研究院,江苏苏州215123 [3]西北工业大学航海学院,陕西西安710072 [4]华北电力大学低品位能源多相流与传热北京市重点实验室,北京102206

出　　处：《推进技术》2022年第10期187-199,共13页Journal of Propulsion Technology

基　　金：国家自然科学基金(52106049,52130608);山东省自然科学基金(ZR2020QE191);江苏省自然科学基金(BK20210113);山东大学青年学者未来计划人才项目(31380089964175)。

摘　　要：为研究应用于燃气轮机余热回收系统的超临界CO_(2)(SCO_(2))径流式透平整机性能,基于RANS(雷诺时均)模型,对透平整机系统内部流场进行数值模拟,获得了SCO_(2)径流式透平整机在起动、升速、自持及额定工况下的运行情况,并针对出口压力变化分析了透平非设计工况下的性能。模拟结果表明:透平起动工况下会发生运行失稳,产生“倒吸”现象且通道内出现大面积的低速区域,但随转速增加流动趋于稳定;叶顶间隙的泄漏流会对透平的性能产生不利影响,额定工况下0.5 mm的间隙使透平减少近47 kW的功率输出,等熵效率降低6%左右;轮背密封可以起到良好密封作用,密封引入气还提高了透平整机的功率和效率;在偏离设计点工况运行时,透平可以有效应对出口压力的变化;通过对比简化通道和全周通道的仿真数据,透平轴功率和等熵效率的误差均在0.5%以内,可知应用简化通道模型仿真能够保证计算精度。因此,在SCO_(2)径流式透平的仿真与应用过程中,研究人员要注重透平低速起动工况下的运行,以及叶顶间隙对这种小尺寸高转速透平机性能的影响。To investigate the performance of the supercritical CO_(2)(SCO_(2)) radial inflow turbine(RIT)for gas turbine waste heat recovery,the internal flow fields of the RITs are simulated with RANS(Reynolds Averaged Navier-Stokes)model.The operating characteristics of the SCO_(2)RITs under starting,speed-rising,self-sustaining and designed condition are studied.The off-design performance of RITs is also analysed through vary⁃ing outlet pressure.The simulation results show that the“inverse suction”phenomenon and a large area of slow-motion in the channel will occur under the starting conditions of the turbine,resulting in unstable operation.How⁃ever,the flow tends to be stable as the speed increases.The leakage flow from the tip clearance reduces the ma⁃chine performance(0.5mm clearance under designed condition reduces 47 kW turbine output power,and the is⁃entropic efficiency is reduced by about 6%).The impeller back seal can play a good sealing role,and the intaken seal gas also improves the power-output and the efficiency of RIT to a certain level.When the RITs running on off-design conditions,the given turbine can effectively cope with changes in outlet pressure.Comparison between the simulations of the simplified passage and the full-circumference passage indicates the error of shaft power and isentropic efficiency is less than 0.5%,showing that the simplified passage has sufficient accuracy for CFD simu⁃lation.Therefore,in the process of simulation and application of SCO_(2)RITs,researchers should pay attention to the operation of the turbine under low-speed starting conditions,and the effect of the tip clearance on the flow of the small-size and high-speed turbines.

关 键 词：燃气轮机 超临界CO_(2) 径流式透平 叶顶间隙 轮背密封 气动性能 

分 类 号：TK14[动力工程及工程热物理—热能工程]