消力池内水流噪声数值模拟分析
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摘要
为解决水噪声试验中因改变边界条件耗时费力的问题,采用了基于VOF和k-ε黏度模型的CFD分析方法,通过改变上游来流量、消力池长度及尾坎高度,对宽顶堰消力池内的各水力要素及水噪声场进行了数值模拟,并且与物理模型试验所得结果进行比较。结果表明:模拟水面线变化趋势与实测水面线误差在30%之内;模拟流速与实测流速误差在30%之内;模拟水噪声在4500~8000Hz之间与实测结果声压级误差在6.5db之间,数值模拟结果与物理模型试验结果较为吻合,说明采用该数学模型模拟低水头情况下宽顶堰消力池内水流的流态与水噪声是可行的。得到了各水力要素及水噪声随流量、消力池长度及尾坎高度变化的规律。相同尾坎高度和消力池长度情况下,上游来流量为12.5,10.3,6.9L·s~(-1)都有水跃产生,同时距上游越近,水面位置处的流速越大;相同上游来流量和消力池长度情况下,尾坎高度对水跃影响明显,同时越靠近宽顶堰位置,水面处的流速越大;相同上游来流量和尾坎高度情况下,消力池长度对水跃影响也比较明显。同时发现水流噪声最大声压值都出现在消力池尾坎附近。
In order to overcome the problem of time consuming as a result of changing boundary conditions in water noise test,the CFD analysis method based on VOF and k-ε viscosity models were used, and numerical simulation of various hydraulic elements and water noise fields in the power tank of a wide roof weir was carried out by changing upstream flow, the length of pool and the height of tail, and the results were compared with numerical simulation to experimental data. The results showed that the error between variation trend of simulated surface line and the measured surface line was less than 30%. The error of simulated velocity and measured velocity was less than 30%. Simulated water noise was between 4500-8000 Hz, whose error with the measured result sound pressure level was around 6.5 db, and the results of numerical simulation were consistent with the experimental results of the physical model, showing that it is feasible to use the mathematical model for simulating the flow state and water noise of water flow in lower water head. The various hydraulic factors and the law of water noise variation with the variation of flow, the length of absorption pool and the height of tail sill were obtained. Under the same height of tail sill and the same length of stilling pool, hydraulic jump emerged with the upper reaches flow rate of 12.5, 10.3 and 6.9 L·s~(-1). The nearer the upstream was, the greater the velocity was in the water surface. With the same upstream flow rate and the length of stilling pool, the height of tail sill obviously affected the height of the water jump, and the closer to the position of the wide top weir, the greater the flow velocity at the surface of the water. The influence of the length of stilling pool on water jump was also obvious under the same flow rate and the same height of tail sill. It was found that the maximum sound pressure of flow noise was in the vicinity of the tail of stilling pool.
In order to overcome the problem of time consuming as a result of changing boundary conditions in water noise test,the CFD analysis method based on VOF and k-ε viscosity models were used, and numerical simulation of various hydraulic elements and water noise fields in the power tank of a wide roof weir was carried out by changing upstream flow, the length of pool and the height of tail, and the results were compared with numerical simulation to experimental data. The results showed that the error between variation trend of simulated surface line and the measured surface line was less than 30%. The error of simulated velocity and measured velocity was less than 30%. Simulated water noise was between 4500-8000 Hz, whose error with the measured result sound pressure level was around 6.5 db, and the results of numerical simulation were consistent with the experimental results of the physical model, showing that it is feasible to use the mathematical model for simulating the flow state and water noise of water flow in lower water head. The various hydraulic factors and the law of water noise variation with the variation of flow, the length of absorption pool and the height of tail sill were obtained. Under the same height of tail sill and the same length of stilling pool, hydraulic jump emerged with the upper reaches flow rate of 12.5, 10.3 and 6.9 L·s~(-1). The nearer the upstream was, the greater the velocity was in the water surface. With the same upstream flow rate and the length of stilling pool, the height of tail sill obviously affected the height of the water jump, and the closer to the position of the wide top weir, the greater the flow velocity at the surface of the water. The influence of the length of stilling pool on water jump was also obvious under the same flow rate and the same height of tail sill. It was found that the maximum sound pressure of flow noise was in the vicinity of the tail of stilling pool.
引文
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[3]戚定满,鲁传敬,何友声.噪声谱的无量纲特性[J].上海交通大学学报,1999,33(10):1210-1212.
[4]梁召峰,周光平,张亦慧,等.空化噪声谱的分离[J].声学技术,2005,24(2):113-116.
[5]张云清.消力池水流噪声的模拟试验[J].中国科技信息,2006(10):85-86.
[6]田茹妍.水滴入水过程及其水噪声试验研究[D].沈阳:沈阳农业大学,2017.
[7]郭维东,谢方芳,胡志华,等.溢流堰下泄水流噪声频谱分析[J].沈阳农业大学学报,2011,42(2):235-238.
[8]郭维东,赵光昱.WES堰下泄水流噪声试验数值模拟分析[J].中国农村水利水电,2015(3):127-131.
[9]杨云,王庭佛.关于“噪声测试中背景噪声修正方法”的探讨[J].噪声与振动控制,2000,2(1):24-26.
[10]孙晓峰.气动声学[M].北京:国防工业出版社,1994.
[11]时启燧.高速水气两相流[M].北京:中国水利水电出版社,2007.
[12]吴持恭.水力学[M].成都:四川大学出版社,2007.
[13]张海澜.理论声学[M].北京:高等教育出版社,2012.
[14]张金明.气动声学数值计算的算法研究[D].南京:南京航空航天大学,2009.
[15]张兆顺.湍流:近代空气动力学丛书[M].北京:国防工业出版社,2002.
[16]刘西云,赵润祥.流体力学中的有限元法与边界元法[M].上海:上海交通大学出版社,1993.
[17]陶文铨.计算流体力学与传热学[M].北京:中国建筑工业出版社,1991.
[18]郭维东,田茹妍,赵光昱.不同条件下橡胶坝下泄水流水噪声研究[J].中国农村水利水电,2016(3):93-95.
[19]郭维东,刘旭冉,李晓东,等.WES堰消力池底板脉动压力与噪声耦合试验[J].人民黄河,2013,35(11):130-132.
[20]胡志华.消力池水流噪声产生机理及影响因素硏究[D].沈阳:沈阳农业大学,2015.