Air entrainment in a vertical dropshaft with limited air supply  

作　　者：Qiang Ding Yiyi Ma David Z.Zhu 

机构地区：[1]Department of Civil Engineering,Zhejiang University [2]Department of Civil and Environmental Engineering,University of Alberta

出　　处：《Theoretical & Applied Mechanics Letters》2018年第5期315-319,362,共6页力学快报（英文版）

基　　金：the financial support from the China Scholarship Council;the Natural Sciences and the Engineering Research Council (NSRC) of Canada

摘　　要：Dropshafts are vertical structures widely used in urban drainage systems and buildings for water transportation.In this paper,a physical model study was conducted to investigate the air entrainment in the dropshaft under various flow regimes with and without air ventilation.Observed from the experiments,the air entrainment mechanisms varied with the water flow regimes in the dropshaft.When there was no water plug formed in the dropshaft,air could be supplied directly from downstream.Once the water plug was formed,while without venting,the air was replenished only from downstream intermittently and then in the form of large air bubble traveling upwards to the airspace at the top;while with venting,air was mainly replenished from the dropshaft top and no large air bubble was observed.The experimental results also showed that the amount of entrained air in the dropshaft with venting was greater than that without venting.Dropshafts are vertical structures widely used in urban drainage systems and buildings for water transportation.In this paper,a physical model study was conducted to investigate the air entrainment in the dropshaft under various flow regimes with and without air ventilation.Observed from the experiments,the air entrainment mechanisms varied with the water flow regimes in the dropshaft.When there was no water plug formed in the dropshaft,air could be supplied directly from downstream.Once the water plug was formed,while without venting,the air was replenished only from downstream intermittently and then in the form of large air bubble traveling upwards to the airspace at the top;while with venting,air was mainly replenished from the dropshaft top and no large air bubble was observed.The experimental results also showed that the amount of entrained air in the dropshaft with venting was greater than that without venting.

关 键 词：AIR ENTRAINMENT AIR supply BUBBLE Flow REGIME Dropshaft 

分 类 号：O3[理学—力学]