叶轮进口条件对串并联离心泵无过载特性的影响
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摘要
为了阐明叶轮进口条件对串并联离心泵无过载性能的影响,该文从速度三角形理论出发,引入进口速度加权平均角度(θ),推导了单级模型泵无压直管叶轮进口条件的最大轴功率,以及相对应的流量的计算公式。在此基础上,研究了串并联离心泵分别应用无压半螺旋和有压半螺旋2种不同叶轮进口条件对无过载性能的影响。结合(computational fluid dynamics,CFD)技术,对各模型泵外特性曲线进行了数值模拟,并搭建试验台分别对单级模型泵和串并联离心泵进行试验。分析表明:计算结果与试验结果能够较好地吻合,在设计工况下,扬程误差和功率误差均在5%以内,从而验证了数值模拟结果的正确性。结果证明:不同叶轮进口条件下,得到的轴向速度分布均匀度变化不大,均匀度较好;而流动偏移角(γ)值有较大的差异,γ值越大越有利于无过载性能的实现。该研究结果为串并联离心泵的无过载研究和开发提供了一定的依据。
Aiming at influences of different inlet flow on non-overload performance of Serial-Parallel Centrifugal Pump(SPCP), establishment of accurate prediction methods is necessary. In fact, the motor of the pump can easily burn out when the pump is working with a large flowing capacity and a high head. A pump is deemed as one with non-overload characteristics when its motor power is larger than 120% of the max shaft power, therefore the non-overloaded characteristic analysis of the SPCP plays a significant role for the safe running of the pump. In this paper, the average angle of inlet velocity(θ), which the impeller inlet flow distribution can be efficiently assessed, is firstly introduced to calculate the maximum shaft power(Pmax) of Single-Stage Model Pump(SSMP) in the case of impeller inlet about no-pressure straight pipe, and relevant flow(tQ′) formula based on velocity triangle theory. Then, having researched the applications of SPCP in the case of two different impeller inlets: No-pressurehalf spiral and pressurehalf spiral. Once more, Computational Fluid Dynamics(CFD) is used to simulate the external characteristic curve of each model, and the enclosed experiment settings are adopted to firstly conduct analysis on the single stage model pump and then on SPCP after modifying the inlet and outlet pipes. In conclusion, analysis indicates that the results of calculation and experiments coincide with each other well. Under the design condition, the head error and the power error are respectively 1.20% and 2.40%, and when the SPCP is in the serial working condition, the head error and the power error are respectively 3.80% and 4.10%; in parallel working condition, the head error and the power error are respectively 2.90% and 3.50%. Therefore, those head errors and power errors are less than 5%, which proves the correctness of numerical simulation. What's more, with the different inlet flow state, axial velocity is distributed uniformly with a little change while the value of γ, the angle between the speed vector of unit nodes and the axial-surface streamline, has a big change. By comparing the values of the γ in different working conditions, it can be found that the non-uniform flow in serial working status is more obvious than that in parallel working status. In addition, a.k.a. θ =γ, by putting these results into formulas, the theoretical tQ′ and Pmax values can be obtained, which are later compared with the experimental results. The tQ′ and Pmax values in non-overloaded working condition have much smaller errors when compared with experiment results, which are respectively 1.38% and 0.47% in the SSMP. However, when the SPCP is in serial working condition, it is easy to go overload. When StQ′ =78.10 m3/h, the pump is at its max power point; in parallel working condition, with PtQ′ =168.50 m3/h, the pump is at its max power point, since the volume of flow is double that of before, for single-stage single-suction centrifugal pumps, it has its max power point only when tQ′ =84.25 m3/h. In actuality, when the rated power of a SPCP motor reachesmotor maxP ≥P, e.g. motorP ≥ 56.64 kW, the pump can achieve its non-overloaded characteristics. This research shows an excellent theoretical innovation, holds a high perspective and provides theoretical reference for designing the hydraulic property of SPCP.
Aiming at influences of different inlet flow on non-overload performance of Serial-Parallel Centrifugal Pump(SPCP), establishment of accurate prediction methods is necessary. In fact, the motor of the pump can easily burn out when the pump is working with a large flowing capacity and a high head. A pump is deemed as one with non-overload characteristics when its motor power is larger than 120% of the max shaft power, therefore the non-overloaded characteristic analysis of the SPCP plays a significant role for the safe running of the pump. In this paper, the average angle of inlet velocity(θ), which the impeller inlet flow distribution can be efficiently assessed, is firstly introduced to calculate the maximum shaft power(Pmax) of Single-Stage Model Pump(SSMP) in the case of impeller inlet about no-pressure straight pipe, and relevant flow(tQ′) formula based on velocity triangle theory. Then, having researched the applications of SPCP in the case of two different impeller inlets: No-pressurehalf spiral and pressurehalf spiral. Once more, Computational Fluid Dynamics(CFD) is used to simulate the external characteristic curve of each model, and the enclosed experiment settings are adopted to firstly conduct analysis on the single stage model pump and then on SPCP after modifying the inlet and outlet pipes. In conclusion, analysis indicates that the results of calculation and experiments coincide with each other well. Under the design condition, the head error and the power error are respectively 1.20% and 2.40%, and when the SPCP is in the serial working condition, the head error and the power error are respectively 3.80% and 4.10%; in parallel working condition, the head error and the power error are respectively 2.90% and 3.50%. Therefore, those head errors and power errors are less than 5%, which proves the correctness of numerical simulation. What's more, with the different inlet flow state, axial velocity is distributed uniformly with a little change while the value of γ, the angle between the speed vector of unit nodes and the axial-surface streamline, has a big change. By comparing the values of the γ in different working conditions, it can be found that the non-uniform flow in serial working status is more obvious than that in parallel working status. In addition, a.k.a. θ =γ, by putting these results into formulas, the theoretical tQ′ and Pmax values can be obtained, which are later compared with the experimental results. The tQ′ and Pmax values in non-overloaded working condition have much smaller errors when compared with experiment results, which are respectively 1.38% and 0.47% in the SSMP. However, when the SPCP is in serial working condition, it is easy to go overload. When StQ′ =78.10 m3/h, the pump is at its max power point; in parallel working condition, with PtQ′ =168.50 m3/h, the pump is at its max power point, since the volume of flow is double that of before, for single-stage single-suction centrifugal pumps, it has its max power point only when tQ′ =84.25 m3/h. In actuality, when the rated power of a SPCP motor reachesmotor maxP ≥P, e.g. motorP ≥ 56.64 kW, the pump can achieve its non-overloaded characteristics. This research shows an excellent theoretical innovation, holds a high perspective and provides theoretical reference for designing the hydraulic property of SPCP.
引文
[1]马士虎,余栋高,谢江辉,等.新型串并联离心泵研制[J].船舶工程,2002,6(23):38-41.Ma Shihu,Yu Donggao,Xie Jianghui,et al.Development of a new-type serial-parallel two-stage centrifugal pump[J].Ship Engineering,2002,6(23):38-41.(in Chinese with English abstract)
[2]赵玉萍.立式两级单吸串并联离心泵:中国,00246745.3[P].2001-07-04.Zhao Yuping,Single suction Vertical type Serial-parallel Two-stage Centrifugal Pump:Chinese,00246745.3[P].2001-07-04.
[3]于萍,孙卫平.船用潜水式串并联离心泵的设计与[J].机电设备,2002,4(23):52-59.Yu Ping,Sun Weiping.Design and research of marine submersible serial-parallel two-stage centrifugal pump[J].Mechanical and Electrical Equipment,2002,4(23):52-59.(in Chinese with English abstract)
[4]从小青,袁寿其,袁丹青,等.无过载排污泵正交试验研究[J].农业机械学报,2005,36(10):67-69.Cong Xiaoqing,Yuan Shouqi,Yuan Danqing,et al.Research of latin square test on non-overload sewage pump[J].Transactions of the Chinese Society for Agricultural Machinery,2005,36(10):67-69.(in Chinese with English abstract)
[5]刘在伦,孙梁森,魏清顺.基于面积比原理的水泵设计方法[J].农业机械学报,2007,38(6):197-199.Liu Zailun,Sun Liangsen,Wei Qingshun.Based on the principle of area ratio of the water pump design method[J].Transactions of the Chinese Society for Agricultural Machinery,2007,38(6):197-199.(in Chinese with English abstract)
[6]王洋,刘洁琼,何文俊.无过载离心泵结构参数优化设计[J].农业工程学报,2012,28(3):33-37.Wang Yang,Liu Jieqiong,He Wenjun.Parameter optimization of non-overload centrifugal pump[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2012,28(3):33-37.(in Chinese with English abstract)
[7]袁寿其,曹武陵,李诗英,等.离心泵无过载理论和设计方法[J].机械工程学报,1992,5(4):252-260.Yuan Shouqi,Cao Wuling,Li Shiying,et al.Theory and design method of non-overload centrifugal pumps[J].Chinese Journal of Mechanical Engineering,1992,5(4):252-260.(in Chinese with English abstract)
[8]袁寿其,曹武陵,金树德,等.农用无过载低比转速离心泵的研究[J].农业工程学报,1993,3(9):79-81.Yuan Shouqi,Cao Wuling,Jin Shude,et al.Research on non-overload low specific speed centrifugal pump for agricultural use[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),1993,3(9):79-81.(in Chinese with English abstract)
[9]严敬.无过载叶轮几何参数的计算[J].农业机械学报,2002,33(3):37-38.Yan Jing.Calculation of geometrical parameters of an impeller with minimal power required[J].Transactions of the Chinese Society for Agricultural Machinery,2002,33(3):37-38.(in Chinese with English abstract)
[10]施卫东,孙新庆,陆伟刚,等.低比转数潜水电泵无过载设计[J].农业机械学报,2010,41(7):36-39.Shi Weidong,Sun Xinqing,Lu Weigang,et al.Non-overload designing research on low specific speed submersible pump[J].Transactions of the Chinese Society for Agricultural Machinery,2010,41(7):36-39.(in Chinese with English abstract)
[11]杨军虎,郭斌,王玥,等.无过载离心泵设计参数与性能关系研究[J].农业机械学报,2012,43(11):119-121.Yang Junhu,Guo Bin,Wang Yue,et al.Relationship of performances and design parameters for non-overload centrifugal pumps[J].Transactions of the Chinese Society for Agricultural Machinery,2012,43(11):119-121.(in Chinese with English abstract)
[12]从小青,袁寿其,袁丹青,等.无过载排污泵理论与设计方法研究[J].农业机械学报,2010,34(6):78-80.Cong Xiaoqing,Yuan Shouqi,Yuan Danqing,et al.Theory and hydraul ic design of non-overload sewagepumps[J].Transactions of the Chinese Society for Agricultural Machinery,2010,34(6):78-80.(in Chinese with English abstract)
[13]Gianfranco Fagnani.The submersible pump-reliability in latest design[J].World Pumps,1985,15(9):261-265.
[14]Anderson H H.Mine Pumps[J].Journal of Mining Society,1984,10(6):34-38.
[15]Stepanoff A J.Centrifugal and Axial Flow Pumps[M].2cd.New York:John Wiley Sons.Inc,1957.
[16]Karassik.Pump Handbook[M].New York:McGrawHill Bool Company,1976.
[17]施卫东,李辉,陆伟刚,等.进口预旋对低比速离心泵无过载性能的影响[J].农业机械学报,2013,44(5):50-53.Shi Weidong,Li Hui,Lu Weigang,et al.Effect of prewhirl flow on non-overload performance of lowspecific-speed centrifugal pumps[J].Transactions of the Chinese Society for Agricultural Machinery,2013,44(5):50-53.(in Chinese with English abstract)
[18]陈伟,陆林广,王刚,等.轴流泵运行工况对叶轮室进口预旋的影响[J].水力发电学报,2012,31(1):31-36.Chen Wei,Lu Linguang,Wang Gang,et al.Influence of axial-flow pump operating condition on the pre-swirl at impeller chamber inlet[J].Journal of hydroelectric power,2012,31(1):31-36.(in Chinese with English abstract)
[19]仇宝云,林海江,黄季艳,等.大型立式轴流泵叶片进口流场及其对水泵影响研究[J].机械工程学报,2005,41(4):65-68.Chou Baoyun,Lin Haijiang,Huang Jiyan,et al.Study on flow field in blade inlet of large vertical axial-flow pump and its in fluence on pump[J].Journal of Drainage and Irrigation Machinery Engineering,2005,41(4):65-68.(in Chinese with English abstract)
[20]Galindo J,Serrano J R,Margot X.Potential of flow pre-whirl at the compressor inlet of automotive engine turbochargers to enlarge surge margin and overcome packaging limitations[J].International Journal of Heat and Fluid Flow,2007,28(3):374-377.
[21]颜红勤,陈松山,葛强,等.钟型进水流道试验及数值模拟[J].排灌机械工程学报,2007,25(5):55-60.Yan Hongqin,Chen Songshan,Ge Qiang,et al.Hydraulic experiment and numerical simulation of campaniform inlet duct[J].Journal of Drainage and Irrigation Machinery Engineering,2007,25(5):55-60.(in Chinese with English abstract)
[22]关醒凡.现代泵技术手册[M].北京:宇航出版社,2010.
[23]Pei Ji,Yuan Shouqi,Yuan Jianping,et al.The influence of the flow rate on periodic flow unsteadiness behaviors in a sewage centrifugal pump[J].Journal of Hydrodynamics,2013,25(5):702-709.
[24]Stel H,Amaral G D L,Negro C O R,et al.Numerical analysis of the fluid flow in the first stage of a two-stage centrifugal pump with a vaned diffuser[J].Journal of Fluids Engineering,2013,135(4):1-9.
[25]YaSuYuKa N,RyoTa F,JunicHiro F.Design method for single-blade centrifugal pump impeller[J].Journal of Fluid Science and Technology,2009,4(3):786-800.
[26]杨孙圣,孔繁余,陈浩,等.叶片进口安放角对液力透平性能的影响[J].中南大学学报:自然版,2013,44(1):108-114.Journal of Central South University:Science and Yang Sunsheng,Kong Fanyu,Chen Hao,et al.Effects of Technology,2013,44(1):108-114.(in Chinese with blade inlet angle on performance of pump as turbine[J].English abstract)
[2]赵玉萍.立式两级单吸串并联离心泵:中国,00246745.3[P].2001-07-04.Zhao Yuping,Single suction Vertical type Serial-parallel Two-stage Centrifugal Pump:Chinese,00246745.3[P].2001-07-04.
[3]于萍,孙卫平.船用潜水式串并联离心泵的设计与[J].机电设备,2002,4(23):52-59.Yu Ping,Sun Weiping.Design and research of marine submersible serial-parallel two-stage centrifugal pump[J].Mechanical and Electrical Equipment,2002,4(23):52-59.(in Chinese with English abstract)
[4]从小青,袁寿其,袁丹青,等.无过载排污泵正交试验研究[J].农业机械学报,2005,36(10):67-69.Cong Xiaoqing,Yuan Shouqi,Yuan Danqing,et al.Research of latin square test on non-overload sewage pump[J].Transactions of the Chinese Society for Agricultural Machinery,2005,36(10):67-69.(in Chinese with English abstract)
[5]刘在伦,孙梁森,魏清顺.基于面积比原理的水泵设计方法[J].农业机械学报,2007,38(6):197-199.Liu Zailun,Sun Liangsen,Wei Qingshun.Based on the principle of area ratio of the water pump design method[J].Transactions of the Chinese Society for Agricultural Machinery,2007,38(6):197-199.(in Chinese with English abstract)
[6]王洋,刘洁琼,何文俊.无过载离心泵结构参数优化设计[J].农业工程学报,2012,28(3):33-37.Wang Yang,Liu Jieqiong,He Wenjun.Parameter optimization of non-overload centrifugal pump[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),2012,28(3):33-37.(in Chinese with English abstract)
[7]袁寿其,曹武陵,李诗英,等.离心泵无过载理论和设计方法[J].机械工程学报,1992,5(4):252-260.Yuan Shouqi,Cao Wuling,Li Shiying,et al.Theory and design method of non-overload centrifugal pumps[J].Chinese Journal of Mechanical Engineering,1992,5(4):252-260.(in Chinese with English abstract)
[8]袁寿其,曹武陵,金树德,等.农用无过载低比转速离心泵的研究[J].农业工程学报,1993,3(9):79-81.Yuan Shouqi,Cao Wuling,Jin Shude,et al.Research on non-overload low specific speed centrifugal pump for agricultural use[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE),1993,3(9):79-81.(in Chinese with English abstract)
[9]严敬.无过载叶轮几何参数的计算[J].农业机械学报,2002,33(3):37-38.Yan Jing.Calculation of geometrical parameters of an impeller with minimal power required[J].Transactions of the Chinese Society for Agricultural Machinery,2002,33(3):37-38.(in Chinese with English abstract)
[10]施卫东,孙新庆,陆伟刚,等.低比转数潜水电泵无过载设计[J].农业机械学报,2010,41(7):36-39.Shi Weidong,Sun Xinqing,Lu Weigang,et al.Non-overload designing research on low specific speed submersible pump[J].Transactions of the Chinese Society for Agricultural Machinery,2010,41(7):36-39.(in Chinese with English abstract)
[11]杨军虎,郭斌,王玥,等.无过载离心泵设计参数与性能关系研究[J].农业机械学报,2012,43(11):119-121.Yang Junhu,Guo Bin,Wang Yue,et al.Relationship of performances and design parameters for non-overload centrifugal pumps[J].Transactions of the Chinese Society for Agricultural Machinery,2012,43(11):119-121.(in Chinese with English abstract)
[12]从小青,袁寿其,袁丹青,等.无过载排污泵理论与设计方法研究[J].农业机械学报,2010,34(6):78-80.Cong Xiaoqing,Yuan Shouqi,Yuan Danqing,et al.Theory and hydraul ic design of non-overload sewagepumps[J].Transactions of the Chinese Society for Agricultural Machinery,2010,34(6):78-80.(in Chinese with English abstract)
[13]Gianfranco Fagnani.The submersible pump-reliability in latest design[J].World Pumps,1985,15(9):261-265.
[14]Anderson H H.Mine Pumps[J].Journal of Mining Society,1984,10(6):34-38.
[15]Stepanoff A J.Centrifugal and Axial Flow Pumps[M].2cd.New York:John Wiley Sons.Inc,1957.
[16]Karassik.Pump Handbook[M].New York:McGrawHill Bool Company,1976.
[17]施卫东,李辉,陆伟刚,等.进口预旋对低比速离心泵无过载性能的影响[J].农业机械学报,2013,44(5):50-53.Shi Weidong,Li Hui,Lu Weigang,et al.Effect of prewhirl flow on non-overload performance of lowspecific-speed centrifugal pumps[J].Transactions of the Chinese Society for Agricultural Machinery,2013,44(5):50-53.(in Chinese with English abstract)
[18]陈伟,陆林广,王刚,等.轴流泵运行工况对叶轮室进口预旋的影响[J].水力发电学报,2012,31(1):31-36.Chen Wei,Lu Linguang,Wang Gang,et al.Influence of axial-flow pump operating condition on the pre-swirl at impeller chamber inlet[J].Journal of hydroelectric power,2012,31(1):31-36.(in Chinese with English abstract)
[19]仇宝云,林海江,黄季艳,等.大型立式轴流泵叶片进口流场及其对水泵影响研究[J].机械工程学报,2005,41(4):65-68.Chou Baoyun,Lin Haijiang,Huang Jiyan,et al.Study on flow field in blade inlet of large vertical axial-flow pump and its in fluence on pump[J].Journal of Drainage and Irrigation Machinery Engineering,2005,41(4):65-68.(in Chinese with English abstract)
[20]Galindo J,Serrano J R,Margot X.Potential of flow pre-whirl at the compressor inlet of automotive engine turbochargers to enlarge surge margin and overcome packaging limitations[J].International Journal of Heat and Fluid Flow,2007,28(3):374-377.
[21]颜红勤,陈松山,葛强,等.钟型进水流道试验及数值模拟[J].排灌机械工程学报,2007,25(5):55-60.Yan Hongqin,Chen Songshan,Ge Qiang,et al.Hydraulic experiment and numerical simulation of campaniform inlet duct[J].Journal of Drainage and Irrigation Machinery Engineering,2007,25(5):55-60.(in Chinese with English abstract)
[22]关醒凡.现代泵技术手册[M].北京:宇航出版社,2010.
[23]Pei Ji,Yuan Shouqi,Yuan Jianping,et al.The influence of the flow rate on periodic flow unsteadiness behaviors in a sewage centrifugal pump[J].Journal of Hydrodynamics,2013,25(5):702-709.
[24]Stel H,Amaral G D L,Negro C O R,et al.Numerical analysis of the fluid flow in the first stage of a two-stage centrifugal pump with a vaned diffuser[J].Journal of Fluids Engineering,2013,135(4):1-9.
[25]YaSuYuKa N,RyoTa F,JunicHiro F.Design method for single-blade centrifugal pump impeller[J].Journal of Fluid Science and Technology,2009,4(3):786-800.
[26]杨孙圣,孔繁余,陈浩,等.叶片进口安放角对液力透平性能的影响[J].中南大学学报:自然版,2013,44(1):108-114.Journal of Central South University:Science and Yang Sunsheng,Kong Fanyu,Chen Hao,et al.Effects of Technology,2013,44(1):108-114.(in Chinese with blade inlet angle on performance of pump as turbine[J].English abstract)