摘要
采用RNG k-ɛ紊流模型和VOF气液两相流模型对大口径的方形管虹吸式出水流道顶部大气团的排出过程进行数值模拟,计算不同高宽比的驼峰一次性带走气团所需要的最小驼峰平均流速v_(a)和气团破碎完全带走需要的驼峰平均流速v_(b)以及排出时间t_(b)。结果显示,随着驼峰高宽比减小,一次性排出驼峰气团需要的流速v_(a)也减小,当驼峰高宽比从0.4下降到0.3时,对应的v_(a)下降了11.6%,但流速仍然很大;在较小的驼峰流速下,对气团进行破碎排出全过程模拟,经过一段时间后,气泡也能全部破碎并排出,最终形成稳定虹吸。在一定范围内,排气时间越长,驼峰处的流速越小,当t_(b)从120 s增加到180 s时,对应的v_(b)降低了16.67%。本研究对于泵站虹吸式出水流道驼峰截面尺寸设计以及泵站稳定运行具有重要意义。
The RNG k-ɛturbulence model and VOF gas-liquid two-phase flow model are used to numerically simulate the exhaust process of the air masses at the top of the large-diameter square pipe siphon outlet channel,and calculating the minimum hump average flow velocity va required for humps with different aspect ratios to take away the air masses at one time and the average hump flow velocity v_(b) and discharge time t_(b) required for air masses fragmentation to completely exhausted.The results show that as the hump aspect ratio decreases,the flow velocity varequired to discharge the hump air masses at one time also decreases.When the hump aspect ratio decreases from 0.4 to 0.3,the corresponding va decreases by 11.6%,but the flow rate is still large.Under a smaller hump flow rate,the whole process of crushing and discharging the air masses is simulated.After a period of time,all the air masses can be broken and discharged,and finally a stable siphon is formed.Within a certain range,the longer the exhaust time,the smaller the flow velocity at the hump.When t_(b) increases from 120s to 180s,the corresponding v_(b) decreases by 16.67%.This study is of great significance to the design of the hump section size of the siphon outlet channel and the stable operation of the pumping station.
作者
陈奇
刘霞
黄可灿
赵亮
常正柏
蒋劲
CHEN Qi;LIU Xia;HUANG Ke-can;ZHAO Liang;CHANG Zheng-bai;JIANG Jin(Hubei Institute of Water Resources and Hydropower Research,Wuhan 430072,Hubei Province,China;Hubei International Irrigation and Drainage Research and Training Center,Wuhan 430072,Hubei Province,China;School of Power and Mechanical Engineering,Wuhan University,Wuhan 430072,Hubei Province,China)
出处
《中国农村水利水电》
北大核心
2022年第10期163-170,181,共9页
China Rural Water and Hydropower
基金
2020年湖北省财政项目水利前期工作(2020-P21800600002)。
