长距离输水工程弥合水锤防护措施研究
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摘要
为选择合适的弥合水锤防护措施,针对长距离重力有压力流输水的特点,建立了水力暂态条件下空气阀数学模型,并采用Bentley Haestad Hammer软件对某长距离输水工程进行了弥合水锤模拟计算。计算结果表明:不设空气阀、布设复合式进排气阀与布设防水锤空气阀3种工况下瞬态升压分别为157.0,200.6 mH_2O及40.0 mH_2O,对应升压比分别为3.75,5.62及1.93;不设空气阀与布设复合式进排气阀条件下均发生了弥合水锤,最大空腔体积分别为350 L和775 L,而布设防水锤空气阀可有效避免弥合水锤;3种工况条件下只有防水锤空气阀升压最低,最大水锤升压较不设空气阀条件下降74.5%,且整体波动最为缓和。通过对3种工况条件下空气阀进排气体积及压力变化情况进行比较分析,可知工况2与工况3空气阀组进排气量差值为2 198～5 558 L,最小压力相差-0.05～0.01 MPa,最大压力相差0.38～0.89 MPa;工况2空气阀在管线末端检修阀关阀过程中发生了剧烈的进排气体积变化,叠加了关阀水锤,而工况3空气阀在整个计算过程中进排气体积变化较为缓和,气体体积流量及水压峰值得到了有效控制,可以认为防水锤型空气阀是弥合水锤的有效防护措施。
The Bentley Haestad Hammer software was used to simulate the water hammer in a long distance water conveyance project. The results showed that the transient pressure rise are 157 m, 200.6 m and 40 m respectively under the conditions of no air valve, setting compound intake and exhaust valve and water-proof hammer air valve, and the corresponding boost ratios are 3.75, 5.62 and 1.93. Under the condition of no air valve and compound air intake and exhaust valve, the water hammer of cavities collapsing had occurred, the maximum cavity volume was 350 L and 775 L respectively, and the waterproof hammer air valve can effectively avoid the water hammer. Under the three operating conditions, only the pressor of water-proof hammer air valve was the lowest, and the maximum pressor was 74.5% lower than that without the air valve, and the overall fluctuation was the slowest. Through comparing and analyzing the incoming and exhausting gas volume and pressure variation under three working conditions, it is known that the difference of incoming and exhausting volume between working condition 2 and working condition 3 is 2198～5558 L, and the minimum pressure difference is-0.05～0.01 MPa, and the maximum pressure difference is 0.38～ 0.89 MPa. In working condition 2, during the process of valve closing at the end of the pipeline, the incoming and exhausting gas volume changed violently, superimposing on the shut-off valve water hammer, while the change of incoming and exhausting volume of the valve in working condition 3 was more relaxed, which has controlled the gas volume and the peak value of water pressure effectively. It can be considered that the water-proof hammer type air valve is an effective protection measure for water hammer of cavities collapsing.
The Bentley Haestad Hammer software was used to simulate the water hammer in a long distance water conveyance project. The results showed that the transient pressure rise are 157 m, 200.6 m and 40 m respectively under the conditions of no air valve, setting compound intake and exhaust valve and water-proof hammer air valve, and the corresponding boost ratios are 3.75, 5.62 and 1.93. Under the condition of no air valve and compound air intake and exhaust valve, the water hammer of cavities collapsing had occurred, the maximum cavity volume was 350 L and 775 L respectively, and the waterproof hammer air valve can effectively avoid the water hammer. Under the three operating conditions, only the pressor of water-proof hammer air valve was the lowest, and the maximum pressor was 74.5% lower than that without the air valve, and the overall fluctuation was the slowest. Through comparing and analyzing the incoming and exhausting gas volume and pressure variation under three working conditions, it is known that the difference of incoming and exhausting volume between working condition 2 and working condition 3 is 2198～5558 L, and the minimum pressure difference is-0.05～0.01 MPa, and the maximum pressure difference is 0.38～ 0.89 MPa. In working condition 2, during the process of valve closing at the end of the pipeline, the incoming and exhausting gas volume changed violently, superimposing on the shut-off valve water hammer, while the change of incoming and exhausting volume of the valve in working condition 3 was more relaxed, which has controlled the gas volume and the peak value of water pressure effectively. It can be considered that the water-proof hammer type air valve is an effective protection measure for water hammer of cavities collapsing.
引文
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[18] 姜越.排气方式对压力输水系统水力过渡过程的影响研究[D].西安:长安大学,2015.
[2] 徐燕.水锤防护措施在某长距离供水系统中的应用[J].水利规划与设计,2017(8):85-87.
[3] 王玲,王福军,黄靖,等.安装有空气阀的输水管路系统空管充水过程瞬态分析[J].水利学报,2017,48(10):1240-1249.
[4] 文丹丹.断流空腔弥合水锤其防护的理论研究和数值模拟[D].成都:西南石油大学,2015.
[5] 王玲.管道快速充水瞬变流的数值研究[D].北京:中国农业大学,2017.
[6] 李小周,朱满林,解建仓,等.不同型式空气阀的水锤防护效果研究[J].西安理工大学学报,2015,31(3):316-321.
[7] Wylie E B,Streeter V L.Fluid Transients[M].New Jersey:Hill International Book Company ,1978.
[8] 梁兴,王敏涛.空气阀流量特性对水锤防护效果的影响分析[J].水科学与工程技术,2008(3):74-76.
[9] 高洁,刘亚明,杨德明.长距离供水系统中空气阀的进排气特性参数研究[J].水电能源科学,2017,35(8):172-174.
[10] 闫明.大流量较平坦长距离有压输水管流水锤防护研究[D].西安:长安大学,2007.
[11] 许从愿,王娟,陶光辉.重力流输水管道水锤防护设计的探讨[J].城镇供水,2017(1):81-84.
[12] 李建军,曹松.长距离废水输送管线水锤及气阻问题解决方案[J].中国给水排水,2015,31(6):85-88.
[13] 林红玉.水锤波速对长距离泵站输水管路中断流水锤的影响与研究[D].西安:长安大学,2010.
[14] 王彬权.基于玻尔兹曼网格法的断流弥合水锤数值计算[D].哈尔滨:哈尔滨工业大学,2017.
[15] 葛光环,寇坤,张军,等.断流弥合水锤最优防护措施的比较与分析[J].中国给水排水,2015,31(1):52-55,60.
[16] 郑兴兴,张健,何喻,等.空气阀的水锤防护性能及其在联合防护中的应用[J].水电能源科学,2014,32(2):167-170,63.
[17] 杨玉思,高学贞,闫明.长距离大管径平坦地区输水管道水锤防护技术[J].给水排水,2010,46(9):174-176.
[18] 姜越.排气方式对压力输水系统水力过渡过程的影响研究[D].西安:长安大学,2015.