不同跌坎体型对掺气减蚀的影响试验研究  

Different size drop experiment on the influence of aeration corrosion reduction research

作　　者：李京蔚[1] 邱勇[1] 胡欣[1] 马运福 陈敬江 

机构地区：[1]云南农业大学水利学院,云南昆明650201

出　　处：《中国水利水电科学研究院学报》2015年第6期461-464,472,共5页Journal of China Institute of Water Resources and Hydropower Research

摘　　要：空蚀不仅破坏泄水建筑物出口的过流表面,严重时还会导致主体工程失事。因此,需要采取一定的工程措施改变高速水流区的压力分布,以提高空穴数,进而达到减轻或消除空蚀破坏的目的,而在边坡位置设置跌坎进行人工强迫掺气正是一种可行的选择。本文针对德党河水库泄洪洞出闸水流可能发生的空化空蚀现象,通过模型试验研究,分别测试了0 m×0 m、0.14 m×0.14 m、0.28 m×0.28 m、0.42 m×0.42 m、0.56 m×0.56 m等不同跌坎断面尺寸对下游泄槽临底压力与流速分布及空穴数变化的影响。成果表明:随着跌坎断面尺寸的逐渐增大,测点空穴数变化明显,当跌坎尺寸超过0.42 m×0.42 m继续增大时,测点空穴数趋于稳定,亦即0.42 m×0.42 m和0.56 m×0.56 m的跌坎体型尺寸能够有效减轻泄槽底板可能出现的空蚀破坏。Cavitation damages flow surface of discharge structures,and may even cause principal structuresto collapse when it is severe. Thus it is necessary to alleviate or prevent the damage of cavitation by alter-ing the pressure distribution of high-speed flow region, which raises the incipient cavitation number. Set-ting aerators with vertical drops at slopes is one of the feasible solutions. In order to protect the flood dis-charge tunnel of the Dedang reservoir from cavitation, we investigatead the influence of cavitation on bot-tom pressures of chute at lower reaches, flow velocity and number of holes by creating aerators of sizes 0m×0m,0.14 m×0.14 m,0.28 m×0.28 m,0.42 m×0.42 m and 0.56 m×0.56 m. Experimental results show that asthe sizes of aerators grow larger, the incipient cavitation number changes obviously. Until it reaches 0.42m×0.42 m,the incipient cavitation number becomes stable. Therefore we can conclude that aerators of sizes0.42 m×0.42 m and 0.56 m×0.56 m can effectively prevent cavitation at the bottom of chutes.

关 键 词：掺气减蚀 跌坎体型 试验研究 

分 类 号：TV131.34[水利工程—水力学及河流动力学]