基于刷丝束叉排管束模型的透平机械刷式密封泄漏流动特性和封严机理研究  

Investigations on the Leakage Flow Characteristics and Sealing Mechanism of Turbomachinery Brush Seals Using Bristle Pack Staggered Tube Bundle Model

作　　者：宋鹏飞 屈杰 高庆[2,3] 李志刚 李军[1] SONG Pengfei;QU Jie;GAO Qing;LI Zhigang;LI Jun(Institute of Turbomachinery,Xi’an Jiaotong University,Xi’an 710049,Shaanxi Province,China;Xi’an Thermal Power Research Institute Co.,Ltd.,Xi’an 710054,Shaanxi Province,China;National Key Laboratory of Efficient Coal Electricity and Carbon Capture Utilization and Storage,Changping District,Beijing 102206,China)

机构地区：[1]西安交通大学叶轮机械研究所,陕西省西安市710049 [2]西安热工研究院有限公司,陕西省西安市710054 [3]高效灵活煤电及碳捕集利用封存全国重点实验室,北京市昌平区102206

出　　处：《发电技术》2024年第5期826-837,共12页Power Generation Technology

基　　金：国家自然科学基金项目(52376029)。

摘　　要：【目的】为获得刷式密封的精细化泄漏流动特性,并揭示其封严机理,建立基于刷丝束叉排管束模型的刷式密封泄漏流动特性数学模型。【方法】数值求解三维雷诺平均纳维-斯托克斯(Reynolds-averaged Navier-Stokes,RANS)方程和剪切应力输运(shear stress transport,SST) k-ω湍流模型,研究刷式密封泄漏量和刷丝束间隙的流动特性。数值模拟获得的泄漏量和压力分布与实验数据吻合一致,验证了数值方法的可靠性。获得了4种压比和转速下的刷式密封泄漏量和刷丝束间的泄漏流动曲线。【结果】随着进出口总静压比的增大,刷丝束内部开始出现细小漩涡并逐渐发展,对泄漏流的阻碍作用变大,刷式密封泄漏量增大的趋势逐渐减缓,最后一排刷丝承受的压差占比从13.1%增加至26.3%。【结论】在所研究的转速范围内,转速对刷式密封的泄漏量的影响可以忽略。压比不同时,泄漏流在末排刷丝与后夹板间隙处的径向流动与围栏高度处轴向流动强度存在差异,导致后夹板下方涡系结构不同,通过刷丝束间精细化泄漏流动分析,揭示了刷式密封的封严机理。研究结果可为三维叉排管束模型在刷式密封泄漏流动研究中的应用提供参考。[Objectives]In order to obtain the refined leakage flow of brush seal and reveal its sealing mechanism,the mathematical model of the leakage flow characteristics of brush seals based on the bristle pack staggered tube bundle model was established.[Methods]The leakage flow rate and characteristics inside the bristle pack of brush seal were investigated by numerical solution of Reynolds-averaged Navier-Stokes(RANS)and shear stress transport(SST)k-ωturbulence model.The leakage and pressure distribution obtained by numerical simulation agrees well with the experimental data,which verifies the reliability of the numerical method.The leakage flow rate and characteristics inside the bristle pack of brush seal was analyzed at four kinds of pressure ratios and rotational speeds.[Results]With the increase of pressure ratio,tiny vortex begins to appear inside the bristle pack and gradually develops.The obstruction effect on the leakage flow becomes larger,which slows down the trend of leakage increment with the pressure ratio.In addition,the pressure drop of the last row of bristle accounting for the overall pressure differential increases from 13.1%to 26.3%.[Conclusions]In the studied range of rotational speed,the influence of rotational speed on the leakage of brush seal can be ignored.When the pressure ratio is different,the difference in the radial flow strength of the leakage flow in the gap between the last row of bristle and the backing plate and the axial flow strength at the fence height will lead to the difference in the vortex system structure under the backing plate.The sealing mechanism of the brush seal was revealed using the refined leakage flow inside the bristle pack.The research results can provide reference for the leakage flow analysis of brush seal using three-dimensional staggered tube bundle model.

关 键 词：透平机械 刷式密封 刷丝束 叉排管束模型 泄漏流动 密封机理 

分 类 号：TK14[动力工程及工程热物理—热能工程]