4.6 Article

Evolution of Water Conveyance Capacity through Hydraulic Transition Processes in Circular Drop Manholes

Journal

WATER
Volume 13, Issue 16, Pages -

Publisher

MDPI
DOI: 10.3390/w13162277

Keywords

transition processes; hydraulics; drop manhole; choking; aerated flow

Funding

  1. China Scholarship Council OF FUNDER [201906710153]

Ask authors/readers for more resources

Circular drop manholes are commonly used in urban drainage networks for steep catchments. Poor downstream hydraulic transition processes can severely impact water conveyance capacity. This paper defines four hydraulic stages, visualizes three types of transition processes and provides four empirical equations for predicting choking risks in different hydraulic stages.
Circular drop manholes are widely implemented for steep catchments in urban drainage networks. Poor downstream hydraulic transition processes of a manhole system, i.e., the formation of hydraulic jump near the outlet entrance, and the sudden transition from free surface to pressurized flow with bursts of air in the outflow pipe can severely constraint the capacity of water conveyance. In this paper, we defined four basic hydraulic stages that indicate where hydraulic transition processes begin and end. The measurements of typical manhole models with different drop heights were conducted under different inflow and outflow conditions. Three types of transition processes covering all flow patterns have resulted into a graphical visualization by analyzing two pairs of dimensionless parameters. The flow inside a circular drop manhole was considered to reach its discharge capacity when the abrupt drop of manhole water level is visible in the fully aerated flow pattern. Four empirical equations revealing the water level filling ratio and discharge efficiency at different hydraulic stages were also presented for further predictions of choking risks.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.6
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available