摘要
氮低温制冷循环系统为高能同步辐射光源提供80 K温区冷量,其最核心的部件为氮透平膨胀机,透平叶顶间隙会改变流场分布,对效率产生较大影响。首先根据设计工况初步确定了氮透平的几何结构,随后利用数值模拟对流场进行计算,研究了叶顶间隙参数对流场分布以及整体效率的影响。结果表明,叶顶间隙的存在会使工作轮入口叶顶出现涡流,改变流场分布。在等叶顶间隙情况下,叶顶间隙相对出口叶高小于1.5%时,间隙每增加0.5%,等熵效率降低1.5%左右;在不等叶顶间隙情况下,径向间隙对透平效率的影响要明显大于轴向间隙。
The nitrogen cryogenic refrigeration cycle provides 80 K cooling capacity for the High Energy Photon Source,its core component is the nitrogen turboexpander.The tip clearance of turboexpander will change the flow field distribution and have a great impact on the efficiency.Firstly,the geometric structure of the nitrogen turboexpander is preliminarily determined according to the design conditions.Then,the flow field is calculated by numerical simulation,and the influence of tip clearance parameter on the flow field distribution and overall efficiency is studied.The results show that the existence of tip clearance will cause a vortex at the top of the inlet of the impeller and change the flow field distribution.In the case of equal tip clearance,when the tip clearance is less than 1.5%of the outlet blade height,the isentropic efficiency decreases by about 1.5%for every 0.5%increase in tip clearance.In the case of unequal tip clearance,the influence of radial clearance on the turboexpander efficiency is significantly greater than that of axial clearance.
作者
张志航
常正则
马长城
霍谊
葛锐
Zhang Zhihang;Chang Zhengze;Ma Changcheng;Huo Yi;Ge Rui(Institute of High Energy Physics Chinese Academy of Sciences,Beijing 100049,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《低温工程》
CAS
CSCD
北大核心
2023年第3期1-9,共9页
Cryogenics
基金
高能同步辐射光源国家重大科技基础设施支持项目
高能同步辐射光源(HEPS)
国家重大科技基础设施项目(发改高技(2017)2173号)。
关键词
氮透平膨胀机
叶顶间隙
通流结构
数值模拟
nitrogen turboexpander
tip clearance
flow structure
numerical simulation
