机匣处理对子午加速轴流风机扩稳的机理研究
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摘要
为揭示叶顶间隙泄漏流动的演变趋势以及前置凸台机匣处理对风机的扩稳机理,采用CFD方法对风机内部流场进行了数值计算,获得了叶顶间隙泄漏流与风机非稳定工作状态的关联及前置凸台机匣处理通过控制主流和叶顶泄漏流,提高风机稳定工作范围的机理。结果表明:随着流量的减小,叶顶间隙泄漏流与主流的交界面不断向上游移动,叶顶间隙泄漏流在叶顶通道内造成的流动堵塞不断扩大,最终导致该风机进入非稳定状态;在小流量时前置凸台机匣处理通过对主流阻挡使部分叶顶泄漏流绕过叶片前缘在相邻流道内往下游流动,减小下游的阻塞区域,从而对风机内部的流动起到一定的稳定作用。
In view of the leakage characteristics of the tip clearance of a meridian accelerated axial fan,forward-step casing is used to effectively reduce the clogging area in the flow channel of the fan when the flow rate is small,and the stable working range of the fan is extended. In order to reveal the evolvement trend of the leaking flow of the tip clearance and the mechanism of the stability extension by the forwardstep casing treatment,CFD method is used to calculate the flow field inside the fan. The correlation between the leakage flow of the blade tip clearance and the unstable working state of the fan is obtained,and the control of the main flow and the leakage flow at the top of the blade by forward-step casing of the front convex station is obtained. The results show that: firstly,with the decrease of the flow rate,the interface between the tip clearance flow and the mainstream is moving upstream. This means that the flow blockage caused by the leakage flow of the tip gap in the vane tip channel is expanding and finally leading to the unstable state of the fan. Secondly,when the flow rate is small,forward-step casing process makes part of the blade tip leakage flow bypass the blade front edge and flow downstream in the adjacent channel by blocking the main stream. The blocking area is reduced and the flow inside the fan is stabilized.
In view of the leakage characteristics of the tip clearance of a meridian accelerated axial fan,forward-step casing is used to effectively reduce the clogging area in the flow channel of the fan when the flow rate is small,and the stable working range of the fan is extended. In order to reveal the evolvement trend of the leaking flow of the tip clearance and the mechanism of the stability extension by the forwardstep casing treatment,CFD method is used to calculate the flow field inside the fan. The correlation between the leakage flow of the blade tip clearance and the unstable working state of the fan is obtained,and the control of the main flow and the leakage flow at the top of the blade by forward-step casing of the front convex station is obtained. The results show that: firstly,with the decrease of the flow rate,the interface between the tip clearance flow and the mainstream is moving upstream. This means that the flow blockage caused by the leakage flow of the tip gap in the vane tip channel is expanding and finally leading to the unstable state of the fan. Secondly,when the flow rate is small,forward-step casing process makes part of the blade tip leakage flow bypass the blade front edge and flow downstream in the adjacent channel by blocking the main stream. The blocking area is reduced and the flow inside the fan is stabilized.
引文
[1]依凤鸣.子午加速轴流风机气流稳定器的设计[J].流体机械,1989(10):19-21.YI Feng-ming. The design of meridian accelerated axial flow fanairflow stabilizer[J]. Fluid Machinery,1989(10):19-21.
[2]田彬,席德科,徐燕飞,等.轴流风机内部流场数值研究[J].风机技术,2004(5):10-13.TIAN Bin,XI De-ke,XU Yan-fei. et al. Numerical study of inter-nal flow field of impeller axial flow fan[J]. Fan Technology,2004(5):10-13.
[3]施卫东,张华,陈斌,等.不同叶顶间隙下的轴流泵内部流场数值计算[J].排灌机械工程学报,2010,28(5):374-377.SHI Wei-dong,ZHANG Hua,CHEN Bin. et al. Numerical calcu-lation of flow field in axial flow pump with different blade clear-ance.[J]. Journal of Mechanical Engineering of Drainage and Ir-rigation,2010,28(5):374-377.
[4]王军,姚瑞锋,刘静,等.低压轴流风机叶顶间隙对叶尖涡及外部性能的影响研究[J].流体机械,2011,39(9):26-29.WANG Jun,YAO Rui-feng,LIU Jing. et al. Influence of tip clear-ance on external performance and tip leakage vortex of low-pressureaxial fan[J]. Fluid Machinery,2011,39(9):26-29.
[5] POGORELOV A,MEINKE M,SCHRDER W. Effects of tip-gapwidth on the flow field in an axial fan[J]. International Journal ofHeat&Fluid Flow,2016,6(1):S0142727X16302764.
[6] THOMPSON D W,KING P I,RABE D C. Experimental investiga-tion of stepped tip gap effects on the performance of a transonic ax-ial-flow compressor rotor[J]. Journal of Turbomachinery,1998,120(3):1213-1213.
[7]李鹏敏.叶顶形态对轴流风机性能及叶片动态特性影响的数值研究[D].华北电力大学,2015.LI Peng-min. Numerical investigation of blade geometry effect onperformance and dynamic characteristics of an axial flow fan[D].North China Electric Power University,2015.
[8] HOYING D A,TAN C S,VO H D,et al. Role of blade passageflow structures in axial compressor rotating stall inception[J].Journal of Turbomachinery,1999,121(4):735-742.
[9] HAH C,BERGNER J,SCHIFFER H P. Short length-scale rotatingstall inception in a transonic axial compressor[J]. Criteria andMechanisms,2006(30):61-70.
[10]刘世文,宁方飞.斜沟槽型处理机匣对压气机性能影响的数值研究[J].燃气涡轮试验与研究,2014(5):5-11.LIU Shi-wen,NING Fang-fei. Numerical investigation of theeffects of sloped trench casing treatment on the aerodynamic per-formance of axial compressor[J]. Test and Study of Gas Turbine,2014(5):5-11.
[11]高鹏,楚武利,吴艳辉,等.梯形间隙结构对斜流风机性能影响的研究[J].风机技术,2007(6):8-11.GAO Peng,CHU Wu-li,WU Yan-hui,et al. Research on the in-fluence of stepped tip gap structure for performance of obliqueflow fan[J]. Fan Technology,2007(6):8-11.
[12]吴艳辉,朱俊强,刘志伟.“前置凸台周向槽式”机匣处理的设计和实验[J].推进技术,2002,23(6):463-467.WU Yan-hui,ZHU Jun-qiang,LIU Zhi-wei. Design and experi-mental investigation on a new grooved treated casing with forward-step in an axial-flow compressor[J]. Propulsion Technology,2002,23(6):463-467.
[13]王福军.计算流体动力学分析:CFD软件原理与应用[M].北京:清华大学出版社,2004.WANG Fu-jun. Computational fluid dynamics analysis:principleand application of CFD software[M]. Beijing:Tsinghua Universi-ty Press,2004.
[14]高景泰,史宝光,马志宏,等.通风机实用技术手册[M].北京:机械工业出版社,2011.GAO Jing-tai,SHI Bao-guang,MA Zhi-hong. et al. Ventilatorpractical technical manual[M]. Beijing:Machinery IndustryPress,2011.
[2]田彬,席德科,徐燕飞,等.轴流风机内部流场数值研究[J].风机技术,2004(5):10-13.TIAN Bin,XI De-ke,XU Yan-fei. et al. Numerical study of inter-nal flow field of impeller axial flow fan[J]. Fan Technology,2004(5):10-13.
[3]施卫东,张华,陈斌,等.不同叶顶间隙下的轴流泵内部流场数值计算[J].排灌机械工程学报,2010,28(5):374-377.SHI Wei-dong,ZHANG Hua,CHEN Bin. et al. Numerical calcu-lation of flow field in axial flow pump with different blade clear-ance.[J]. Journal of Mechanical Engineering of Drainage and Ir-rigation,2010,28(5):374-377.
[4]王军,姚瑞锋,刘静,等.低压轴流风机叶顶间隙对叶尖涡及外部性能的影响研究[J].流体机械,2011,39(9):26-29.WANG Jun,YAO Rui-feng,LIU Jing. et al. Influence of tip clear-ance on external performance and tip leakage vortex of low-pressureaxial fan[J]. Fluid Machinery,2011,39(9):26-29.
[5] POGORELOV A,MEINKE M,SCHRDER W. Effects of tip-gapwidth on the flow field in an axial fan[J]. International Journal ofHeat&Fluid Flow,2016,6(1):S0142727X16302764.
[6] THOMPSON D W,KING P I,RABE D C. Experimental investiga-tion of stepped tip gap effects on the performance of a transonic ax-ial-flow compressor rotor[J]. Journal of Turbomachinery,1998,120(3):1213-1213.
[7]李鹏敏.叶顶形态对轴流风机性能及叶片动态特性影响的数值研究[D].华北电力大学,2015.LI Peng-min. Numerical investigation of blade geometry effect onperformance and dynamic characteristics of an axial flow fan[D].North China Electric Power University,2015.
[8] HOYING D A,TAN C S,VO H D,et al. Role of blade passageflow structures in axial compressor rotating stall inception[J].Journal of Turbomachinery,1999,121(4):735-742.
[9] HAH C,BERGNER J,SCHIFFER H P. Short length-scale rotatingstall inception in a transonic axial compressor[J]. Criteria andMechanisms,2006(30):61-70.
[10]刘世文,宁方飞.斜沟槽型处理机匣对压气机性能影响的数值研究[J].燃气涡轮试验与研究,2014(5):5-11.LIU Shi-wen,NING Fang-fei. Numerical investigation of theeffects of sloped trench casing treatment on the aerodynamic per-formance of axial compressor[J]. Test and Study of Gas Turbine,2014(5):5-11.
[11]高鹏,楚武利,吴艳辉,等.梯形间隙结构对斜流风机性能影响的研究[J].风机技术,2007(6):8-11.GAO Peng,CHU Wu-li,WU Yan-hui,et al. Research on the in-fluence of stepped tip gap structure for performance of obliqueflow fan[J]. Fan Technology,2007(6):8-11.
[12]吴艳辉,朱俊强,刘志伟.“前置凸台周向槽式”机匣处理的设计和实验[J].推进技术,2002,23(6):463-467.WU Yan-hui,ZHU Jun-qiang,LIU Zhi-wei. Design and experi-mental investigation on a new grooved treated casing with forward-step in an axial-flow compressor[J]. Propulsion Technology,2002,23(6):463-467.
[13]王福军.计算流体动力学分析:CFD软件原理与应用[M].北京:清华大学出版社,2004.WANG Fu-jun. Computational fluid dynamics analysis:principleand application of CFD software[M]. Beijing:Tsinghua Universi-ty Press,2004.
[14]高景泰,史宝光,马志宏,等.通风机实用技术手册[M].北京:机械工业出版社,2011.GAO Jing-tai,SHI Bao-guang,MA Zhi-hong. et al. Ventilatorpractical technical manual[M]. Beijing:Machinery IndustryPress,2011.