Water hammer protection characteristic of combined air vessel and pressure relief valve
LI Nan1, ZHANG Jian1*, SHI Lin1, CHEN Xuyun1, ZHANG Xiaoying2
1. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing, Jiangsu 210098, China; 2. College of Hydraulic and Civil Engineering, Xinjiang Agricultural University, Urumqi, Xinjiang 830052, China
Abstract：A water hammer protection scheme, i.e. combined air vessel and pressure relief valve installation, was proposed, then the mathematical model for the whole system including air vessel, hydraulic control butterfly valve and pressure relief valve was established based on the method of characteristics to simulate the transient pressure variation process in the system during pump stopping period. Based on a specific water supply project, three protection measures, such as single air vessel scheme, combined air vessel and hydraulic control butterfly valve scheme and combined air vessel and pressure relief valve scheme, were assessed in terms of water hammer effect during pump stopping period. Specially, a sensitivity analysis was carried out on the opening and closing rules of the pressure relief valve as the shape parameters of the air vessel volume were fixed. The results showed that the combined air vessel and hydraulic control butterfly valve scheme is unfavorable to positive and negative water hammer protection, and the combined air vessel and pressure relief valve scheme has a good effect on both positive and negative water hammer protection. Compared with single air vessel protection scheme, the maximum stress in the high-pressure pipe wall was decreased from 1.343 MPa to 1.087 MPa, and the safety margin was increased by 9.4%. The volume of air vessel was reduced from 200 m3 to 160 m3. The pressure relief valve should be opened fully within 5 seconds, and the duration after opening should be close to one phase length(the time for traveling one wavelength).
李楠,张健*,石林,陈旭云,张小莹. 空气罐与超压泄压阀联合水锤防护特性[J]. 排灌机械工程学报, 2020, 38(3): 254-260.
LI Nan,ZHANG Jian*,SHI Lin,CHEN Xuyun,ZHANG Xiaoying. Water hammer protection characteristic of combined air vessel and pressure relief valve. Journal of Drainage and Irrigation Machinery Engin, 2020, 38(3): 254-260.
