离心叶轮内部流动特征与性能的数值研究
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摘要
离心压缩机在许多领域都起着非常重要的作用,运行时消耗大量的能源,分析离心压缩机内部流场的流动特性,改进结构,提高效率,是研究离心压缩机的主要课题。随着计算机技术的发展,数值模拟成为分析离心压缩机内部流动的重要手段之一。
本文对一叶轮直径为0.4m,机器马赫数为0.86的离心压缩机进行了数值模拟和分析。采用综合手段完成了离心压缩机整级的几何建模和网格划分,与其它建模方式比较,本文方法可以快速建立模型几何结构、生成高质量网格。在此基础上计算了从喘振到阻塞流量的全量程工况,给出了离心压缩机级的多变效率曲线和能量头系数曲线。由性能曲线得出,当流量系数为0.12047时,多变效率达到最高值,为86.74%。
分别对三种典型工况下的离心压缩机内部流场进行了流动特性分析,小流量工况、设计工况和大流量工况对应的流量系数分别为0.1045、0.1205和0.1460。结果发现,不同工况下,随着流量的增加,叶轮和扩压器部分的流动变差;由盘侧至盖侧,离心压缩机内部流动逐渐变得紊乱。在回流器内部,大流量工况下的流动相比小流量工况和设计点工况具有更小的分离区。各流动区域的静压等值线图的变化趋势与速度矢量图相一致。在各运行工况下,叶轮盖侧均存在一低压区,而在弯道的盖侧和回流器的盘侧则有一高压区,这两个区域内的流动可能引起离心压缩机明显的能量损失。
分析对比了扩压器与弯道以及回流器部分的损失,由损失百分比曲线得出,在小流量区域,随着流量的增加流动损失逐渐减小,在设计工况附近流动损失达到最低值,在大流量区域,随着流量的增加损失逐渐增大。
本文对离心压缩机内部流场流动特性的分析,为量化离心压缩机结构对流场的影响和减少级损失提供了数值依据,有助于进一步的理论研究,为离心压缩机的设计以及解决工程实际问题提供指导。
Centrifugal compressors play an important role in lots of fields, and amount of energy is used to operate. Analyzing the characteristics of centrifugal compressor flow field, improving structure, raising efficiency, are the main topics of centrifugal compressors research. With the development of computer technology, numerical simulation method becomes an important way of analyzing the flow of centrifugal compressors.
In this paper, a centrifugal compressor, with the impeller tip diameter 0.4m and Mach number 0.86, was studied. Poly-means were used here to complete the geometric modeling and meshing of whole flow field of the centrifugal compressor stage. Compared to other modeling methods, it was easier to create the model of geometry structure and generate high quality mesh in the paper. Basing on this, the inner flow of stage from surging to blocking flows was calculated here. Then the charts of polytrophic efficiency and energy head coefficient of centrifugal compressor were presented. From the polytrophic efficiency chart, it showed that the highest value of polytrophic efficiency was 0.8647 corresponding flow coefficient 0.12047.
The flow field characteristics of centrifugal compressor in three key operating conditions were discussed respectively. The flow coefficients of small flow rate condition, design condition and large flow rate condition were 0.1045, 0.1205 and 0.1460. In different conditions, with the increasing of flow rate, the flow in impeller and diffuser became worse; from hub to shroud, flow turned more complexity. In return channel, there were less separation areas in large flow rate condition than small flow rate condition and design condition. Variety of static pressure contour in any area corresponded with that of velocity. In all conditions, there were a low pressure area in the hub of impeller, and two high pressure areas in the hub of bend and the shroud of return channel. The flow in these areas might cause more energy loss of centrifugal compressor.
The flow loss in diffuser, bend and return channel part was analyzed. The chart of loss percentage showed that, in small flow rate conditions, with the flow rate increasing, the flow loss became small, there was a lowest loss percentage near design condition; in large flow rate conditions, with the flow rate increasing, the flow loss became large again.
The Analysis of the flow characteristics of centrifugal compressor in this paper provided a numerical foundation of analyzing the effect of centrifugal compressor structure to flow field and reducing the flow loss of the stage, it is helpful for further study and able to instruct the designing of centrifugal compressor and solving engineering problems.
本文对一叶轮直径为0.4m,机器马赫数为0.86的离心压缩机进行了数值模拟和分析。采用综合手段完成了离心压缩机整级的几何建模和网格划分,与其它建模方式比较,本文方法可以快速建立模型几何结构、生成高质量网格。在此基础上计算了从喘振到阻塞流量的全量程工况,给出了离心压缩机级的多变效率曲线和能量头系数曲线。由性能曲线得出,当流量系数为0.12047时,多变效率达到最高值,为86.74%。
分别对三种典型工况下的离心压缩机内部流场进行了流动特性分析,小流量工况、设计工况和大流量工况对应的流量系数分别为0.1045、0.1205和0.1460。结果发现,不同工况下,随着流量的增加,叶轮和扩压器部分的流动变差;由盘侧至盖侧,离心压缩机内部流动逐渐变得紊乱。在回流器内部,大流量工况下的流动相比小流量工况和设计点工况具有更小的分离区。各流动区域的静压等值线图的变化趋势与速度矢量图相一致。在各运行工况下,叶轮盖侧均存在一低压区,而在弯道的盖侧和回流器的盘侧则有一高压区,这两个区域内的流动可能引起离心压缩机明显的能量损失。
分析对比了扩压器与弯道以及回流器部分的损失,由损失百分比曲线得出,在小流量区域,随着流量的增加流动损失逐渐减小,在设计工况附近流动损失达到最低值,在大流量区域,随着流量的增加损失逐渐增大。
本文对离心压缩机内部流场流动特性的分析,为量化离心压缩机结构对流场的影响和减少级损失提供了数值依据,有助于进一步的理论研究,为离心压缩机的设计以及解决工程实际问题提供指导。
Centrifugal compressors play an important role in lots of fields, and amount of energy is used to operate. Analyzing the characteristics of centrifugal compressor flow field, improving structure, raising efficiency, are the main topics of centrifugal compressors research. With the development of computer technology, numerical simulation method becomes an important way of analyzing the flow of centrifugal compressors.
In this paper, a centrifugal compressor, with the impeller tip diameter 0.4m and Mach number 0.86, was studied. Poly-means were used here to complete the geometric modeling and meshing of whole flow field of the centrifugal compressor stage. Compared to other modeling methods, it was easier to create the model of geometry structure and generate high quality mesh in the paper. Basing on this, the inner flow of stage from surging to blocking flows was calculated here. Then the charts of polytrophic efficiency and energy head coefficient of centrifugal compressor were presented. From the polytrophic efficiency chart, it showed that the highest value of polytrophic efficiency was 0.8647 corresponding flow coefficient 0.12047.
The flow field characteristics of centrifugal compressor in three key operating conditions were discussed respectively. The flow coefficients of small flow rate condition, design condition and large flow rate condition were 0.1045, 0.1205 and 0.1460. In different conditions, with the increasing of flow rate, the flow in impeller and diffuser became worse; from hub to shroud, flow turned more complexity. In return channel, there were less separation areas in large flow rate condition than small flow rate condition and design condition. Variety of static pressure contour in any area corresponded with that of velocity. In all conditions, there were a low pressure area in the hub of impeller, and two high pressure areas in the hub of bend and the shroud of return channel. The flow in these areas might cause more energy loss of centrifugal compressor.
The flow loss in diffuser, bend and return channel part was analyzed. The chart of loss percentage showed that, in small flow rate conditions, with the flow rate increasing, the flow loss became small, there was a lowest loss percentage near design condition; in large flow rate conditions, with the flow rate increasing, the flow loss became large again.
The Analysis of the flow characteristics of centrifugal compressor in this paper provided a numerical foundation of analyzing the effect of centrifugal compressor structure to flow field and reducing the flow loss of the stage, it is helpful for further study and able to instruct the designing of centrifugal compressor and solving engineering problems.
引文
[1]冀春俊,王宇,离心压缩机末级最佳D4/D2值的数值研究,FLUID MACHINERY,2009,37(4):14-17
[2]王尚锦,离心压缩机三元流动理论与应用,西安交通大学出版社,1991
[3]吴文权,漩涡的场特性与物质性-离散涡方法基础,工程热物理学报,1997,18(1)
[4]蔡睿贤,完全气体一元变截面有传热有摩擦流动的一些不定常解析解,工程热物理学报,1996,17(2):156-160
[5]刘高联,转轮内全三元可压缩理想流体非定常有旋流动的位势函数及其变分原理,中国工程热物理学会热机气动热力学学术会议论文集,962038,武夷山,1996
[6]Xu J Z et al. Three Dimensional Incompressible Flow Solution of an Axial Compressor Using Pseadostream-Function, ASME Paper 89-GB-319, 1997
[7]Harri P, Hannu E, Arttu R. Computational and Experimental Study of an Industrial Centrifugal Compressor Volute, Journal of Thermal Science, 2000, 9(1): 77-84
[8]傅烈虎,李青冬,徐荣吉,变转速制冷压缩机的实验研究,制冷与空调,2008,8(3):44-46
[9]周莉,蔡元虎,离心压缩机内进口导叶后面流场的实验研究,实验流体力学,2008,22(1):17-20
[10]刘小民,席光,王尚锦,叶片扩压器对改进离心式压缩机性能的实验研究,化工机械,1998,25(2):73-75
[11]刘小民,张春梅,席光,超窄流道小流量离心压缩机的实验研究,FLUID MACHINERY,2001,29(6):5-8
[12]陈德江,王尚锦,离心式压缩机叶片扩压器的实验研究,流体机械,1997,25(11):3-6
[13]赵荣珍,李超,无叶扩压器不同进口条件时流场的实验研究,甘肃工业大学学报,1999,25(4):45-47
[14]刘正先,离心叶轮内三维湍流流场的LDV测量,航空动力学报,2002,17(3)
[15]陈党民,吴海燕,张朝磊,主要气动设计参数的分析研究,风机技术,2006,3:1-4
[16]陈西,苗永淼,离心式压缩机叶轮内部流场的数值计算,工程热物理学报,1992,18(3):277-281
[17]赵斌,孙铁,离心压缩机叶轮内部流场的数值模拟,压缩机技术,2007,1(16):16-20
[18]胡小文,闻苏平,席光,离心叶轮的速度系数对级性能的影响,西安交通大学学报,2008,42(7):807-811
[19]刘正先,黄章峰,李俊峰,人口非均匀性对离心压缩机级性能影响的数值分析,FLUID MACHINERY,2008,36(9):16-20
[20]冀春俊,肖蕾,离心压缩机小流量级扩压器的分析与优化,设计计算,2005,2:15-17
[21]Mcnally W D, Sockol P M. Review-Computational Method for Internal Flow With Emphasis on Turbo-machinery, Journal of Fluids Engineering, 1985, 107:6-22
[22]Katanis, et al. Use of Arbitrary Quasi-Orthogonal Line for calculating Flow Distribution in the Meridional Plane of Turbo-machine, NASA TND-2546,1964
[23]Hirsch C, Wargee G. A Finite Element Method for Through flow calculation in Turbomanchines,ASME Journal of Fluids Engineering, 1976,98(3):403-421
[24]Senno Y, Nakase Y. A Blade Theory of an Impeller with an Arbitrary Surface of Revolution, ASME J. of Engineering for Power, 1971,93(3):454-460
[25]Norvak R, Hearsey r. a Nearly Three-Dimensional Inter-Blade Computing System for Turbomachinery,ASME Journal of Fluids Engineering
[26]Hathaway M D, Chriss R M, Strazisar A J, et al. Laser Anemometer Measurement of the Three-Dimensional Rotor Flow Field in the NASA Low-Speed Centrifugal Compressor: NASA Technical Paper, ARL-TR-333, 1995
[27]Krimerman Y, Alder D. The Complete Three-Dimensional Calculation of the Compressible Flow Field in Turbo Impeller, Journal of mechanical Engineering Science, 1978, 20:149-158
[28]高慧,可压缩效应对平板湍流边界层影响的直接数值模拟,中国石油大学学报(自然科学版),2009,33(5):89-103
[29]刘滔,林文贤,高文峰,低Pr数流体自然对流边界层流动的直接数值模拟,力学与实践,2008,30(4):28-35
[30]黄振宇,缪国平,大涡模拟在水下航行体周围黏性流场计算中的初步应用,水动力学研究与进展,2006,21(2):190-197
[31]汪怡平,谷正气,李伟平,汽车气动噪声数值计算分析,汽车工程,2009,31(4):385-388
[32]梁开洪,曹树良,陈炎等,轴流泵叶轮内部流场大涡模拟及分析,流体机械,2009,37(11):9-14
[33]武宇琼,吴振宇,王超,基于大涡模拟的不同攻角下导叶全流道数值分析,水利水电工程设计,2009,28(4):50-52
[34]朱晖,杨志刚,DES模型在类车体外流场计算中的对比研究,汽车工程,2008,30(9):796-800
[35]李栋,Igor M S,中村佳朗,翼型失速特性的RANS方法与DES方法数值模拟对比分析,西北工业大学学报,2006,24(2):228-231
[36]方坤,计算流体力学的几种常用软件,煤炭技术,2006,25(12)
[37]Florian M,Robin L. ANSYS CFX对飞机气动阻力的精确模拟,中国制造业信息化,2005,7:72
[38]李盟,中国商飞公司将采用安世亚太CFD仿真技术,航空精密制造技术,2008,44(6):10
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[2]王尚锦,离心压缩机三元流动理论与应用,西安交通大学出版社,1991
[3]吴文权,漩涡的场特性与物质性-离散涡方法基础,工程热物理学报,1997,18(1)
[4]蔡睿贤,完全气体一元变截面有传热有摩擦流动的一些不定常解析解,工程热物理学报,1996,17(2):156-160
[5]刘高联,转轮内全三元可压缩理想流体非定常有旋流动的位势函数及其变分原理,中国工程热物理学会热机气动热力学学术会议论文集,962038,武夷山,1996
[6]Xu J Z et al. Three Dimensional Incompressible Flow Solution of an Axial Compressor Using Pseadostream-Function, ASME Paper 89-GB-319, 1997
[7]Harri P, Hannu E, Arttu R. Computational and Experimental Study of an Industrial Centrifugal Compressor Volute, Journal of Thermal Science, 2000, 9(1): 77-84
[8]傅烈虎,李青冬,徐荣吉,变转速制冷压缩机的实验研究,制冷与空调,2008,8(3):44-46
[9]周莉,蔡元虎,离心压缩机内进口导叶后面流场的实验研究,实验流体力学,2008,22(1):17-20
[10]刘小民,席光,王尚锦,叶片扩压器对改进离心式压缩机性能的实验研究,化工机械,1998,25(2):73-75
[11]刘小民,张春梅,席光,超窄流道小流量离心压缩机的实验研究,FLUID MACHINERY,2001,29(6):5-8
[12]陈德江,王尚锦,离心式压缩机叶片扩压器的实验研究,流体机械,1997,25(11):3-6
[13]赵荣珍,李超,无叶扩压器不同进口条件时流场的实验研究,甘肃工业大学学报,1999,25(4):45-47
[14]刘正先,离心叶轮内三维湍流流场的LDV测量,航空动力学报,2002,17(3)
[15]陈党民,吴海燕,张朝磊,主要气动设计参数的分析研究,风机技术,2006,3:1-4
[16]陈西,苗永淼,离心式压缩机叶轮内部流场的数值计算,工程热物理学报,1992,18(3):277-281
[17]赵斌,孙铁,离心压缩机叶轮内部流场的数值模拟,压缩机技术,2007,1(16):16-20
[18]胡小文,闻苏平,席光,离心叶轮的速度系数对级性能的影响,西安交通大学学报,2008,42(7):807-811
[19]刘正先,黄章峰,李俊峰,人口非均匀性对离心压缩机级性能影响的数值分析,FLUID MACHINERY,2008,36(9):16-20
[20]冀春俊,肖蕾,离心压缩机小流量级扩压器的分析与优化,设计计算,2005,2:15-17
[21]Mcnally W D, Sockol P M. Review-Computational Method for Internal Flow With Emphasis on Turbo-machinery, Journal of Fluids Engineering, 1985, 107:6-22
[22]Katanis, et al. Use of Arbitrary Quasi-Orthogonal Line for calculating Flow Distribution in the Meridional Plane of Turbo-machine, NASA TND-2546,1964
[23]Hirsch C, Wargee G. A Finite Element Method for Through flow calculation in Turbomanchines,ASME Journal of Fluids Engineering, 1976,98(3):403-421
[24]Senno Y, Nakase Y. A Blade Theory of an Impeller with an Arbitrary Surface of Revolution, ASME J. of Engineering for Power, 1971,93(3):454-460
[25]Norvak R, Hearsey r. a Nearly Three-Dimensional Inter-Blade Computing System for Turbomachinery,ASME Journal of Fluids Engineering
[26]Hathaway M D, Chriss R M, Strazisar A J, et al. Laser Anemometer Measurement of the Three-Dimensional Rotor Flow Field in the NASA Low-Speed Centrifugal Compressor: NASA Technical Paper, ARL-TR-333, 1995
[27]Krimerman Y, Alder D. The Complete Three-Dimensional Calculation of the Compressible Flow Field in Turbo Impeller, Journal of mechanical Engineering Science, 1978, 20:149-158
[28]高慧,可压缩效应对平板湍流边界层影响的直接数值模拟,中国石油大学学报(自然科学版),2009,33(5):89-103
[29]刘滔,林文贤,高文峰,低Pr数流体自然对流边界层流动的直接数值模拟,力学与实践,2008,30(4):28-35
[30]黄振宇,缪国平,大涡模拟在水下航行体周围黏性流场计算中的初步应用,水动力学研究与进展,2006,21(2):190-197
[31]汪怡平,谷正气,李伟平,汽车气动噪声数值计算分析,汽车工程,2009,31(4):385-388
[32]梁开洪,曹树良,陈炎等,轴流泵叶轮内部流场大涡模拟及分析,流体机械,2009,37(11):9-14
[33]武宇琼,吴振宇,王超,基于大涡模拟的不同攻角下导叶全流道数值分析,水利水电工程设计,2009,28(4):50-52
[34]朱晖,杨志刚,DES模型在类车体外流场计算中的对比研究,汽车工程,2008,30(9):796-800
[35]李栋,Igor M S,中村佳朗,翼型失速特性的RANS方法与DES方法数值模拟对比分析,西北工业大学学报,2006,24(2):228-231
[36]方坤,计算流体力学的几种常用软件,煤炭技术,2006,25(12)
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