|
|
Experiment and numerical simulation of hydraulic transients in branched pipe network |
(1. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China; 2. Institute of Watersaving Agriculture in Arid Areas of China(IWSA), Northwest A&F University, Yangling, Shaanxi 712100, China) |
|
|
Abstract The water hammer pressure and fluctuation in a branched pipe network were studied by experiment and the method of characteristics (MOC) when the valve is closed. In experiment a pressure sensor was used to monitor water hammer pressure and fluctuation and the angular displacement sensor was adopted to measure the closing time and opening of the valve. The results showed that the MOC can better predict the maximum water hammer pressure caused by valve closing in the network with a relative error of less than 13%. The pressure wave attenuation in simulation is slower than in experiment because the friction factor of steady flow is used in the simulation. Based on that analysis, the transient flows generated by other five closing schemes of valve have been simulated numerically. It was shown that the maximum water hammer pressure was generated in the network when the two valves at the network end were closed simultaneously; suggesting this case should be avoided in applications. The maximum water hammer pressure was reduced with increasing closing time. For a constant closing time, the maximum water hammer pressure generated by a curved line closing scheme or a twostage straight line closing scheme was lower than that by the one straight line scheme. For the twostage straight line closing scheme, the closing time of the first stage should properly be extended to reduce the maximum water hammer pressure.
|
Received: 06 December 2012
Published: 31 May 2013
|
|
|
|
[1]金宏智, 严海军, 钱一超. 国外节水灌溉工程技术发展分析[J]. 农业机械学报, 2010, 41(S1): 59-63.Jin Hongzhi, Yan Haijun, Qian Yichao. Overseas development of watersaving irrigation engineering technology[J]. Transactions of the Chinese Society for Agricultural Machinery, 2010, 41(S1): 59-63. (in Chinese)[2]魏闯, 李明思, 李东伟, 等. PVC管网中支管连接方式对干管水锤压力叠加的影响[J]. 农业工程学报, 2012, 28(18): 88-94.Wei Chuang, Li Mingsi, Li Dongwei, et al. Effects of connecting patterns of branch pipes on superposed water hammer pressure in trunk pipe for the PVC pipeline system[J]. Transactions of the CSAE, 2012, 28(18): 88-94.(in Chinese)[3]Wylie E B, Streeter V L. Fluid Transients[M]. New York: McGrawHill International Book Company, 1978.[4]Kwon H J, Lee J J. Computer and experimental models of transient flow in a pipe involving backflow reventers[J]. Journal of Hydraulic Engineering, 2008,134(4): 426-434.[5]Afshar M H, Rohani M. Water hammer simulation by implicit method of characteristic[J]. International Journal of Pressure Vessels and Piping, 2008, 85(12): 851-859.[6]Tian Wenxi, Su G H, Wang Gaopeng, et al. Numerical simulation and optimization on valveinduced water hammer characteristics for parallel pump feedwater system[J].Annals of Nuclear Energy, 2008,35(12):2280-2287.[7]Li Zhifeng, Wu Peng, Wu Dazhuan, et al. Experimental and numerical study of transient flow in a centrifugal pump during startup[J]. Journal of Mechanical Science and Technology, 2011,25(3):749-757.[8]Sadafi M, Riasi A, Nourbakhsh S A. Cavitating flow during water hammer using a generalized interface vaporous cavitation model[J]. Journal of Fluids and Structures, 2012,34:190-201.[9]马飞, 曲世琳, 吴一民. 给水管网非恒定流动数值计算方法[J]. 北京科技大学学报, 2009, 31(4): 423-427.Ma Fei, Qu Shilin, Wu Yimin. Numeriacl calculation methods of water distribution systems in hydraulic transient conditions[J]. Journal of University of Science and Technology Beijing, 2009,31(4): 423-427. (in Chinese)[10]杨开林. 控制输水管道瞬态液柱分离的空气阀调压室[J]. 水利学报, 2011, 42(7):805-811.Yang Kailin. Airvalve surge tank for controlling liquid column separation in water supply projects[J]. Journal of Hydraulic Engineering, 2011,42(7):805-811.(in Chinese)[11]刘竹青, 毕慧丽, 王福军. 空气阀在有压输水管路中的水锤防护作用[J]. 排灌机械工程学报, 2011, 29(4): 333-337.Liu Zhuqing, Bi Huili, Wang Fujun. Effect of air valves on water hammer projection in pressure pipelines[J]. Journal of Drainage and Irrigation Machinery Engineering, 2011, 29(4): 333-337.(in Chinese)[12]王文全, 张立翔, 闫妍, 等. 长距离输水系统停泵水锤的数值模拟[J]. 农业机械学报, 2010, 41(11): 63-66.Wang Wenquan, Zhang Lixiang, Yan Yan, et al. Numerical simulation of the water hammer caused by accidental pumpstop in long water supply systems[J]. Transactions of the Chinese Society for Agricultural Machinery, 2010, 41(11): 63-66. (in Chinese)[13]岑康, 李长俊, 廖柯熹, 等. 液体管道瞬变流摩阻的计算方法[J]. 西南石油学院学报, 2005, 27(3): 76-79.Cen Kang, Li Changjun, Liao Kexi, et al. Calculation method of friction losses with transient flow in pipe[J]. Journal of Southwest Petroleum Institute, 2005, 27(3):76-79.(in Chinese)[14]Vardy A E, Brown J M B. Transient turbulent friction in smooth pipe flows[J]. Journal of Sound and Vibration, 2003, 259(5):1011-1036. |
|
|
|