No abstract

No abstract

No abstract

This study presents a quantitative assessment of urbanization effects on hydrological runoff and drainage network in the city of Hohhot, China. The evolution of urban spatial morphology for the historical years (1987-2010) and projected year (2020) is described by changes in geographic information system (GIS)-based land use maps and further represented in hydrological parameters in the Storm Water Management Model (SWMM) simulation. The results show the levels of service of historical drainage were too low to have dominant impacts on flood risks, and hence a significant upward trend in catchment runoff response was observed over time. Comparisons with changes in system overloading indicate that the relative increase in flood risk is greatest at the early stage of urbanization with relatively low levels of development. The proposed adaptation measures based on a cost-effective optimal approach was found feasible to significantly improve the drainage performance and mitigate the increasing flooding impacts.

No abstract

A method to measure the superficial velocity of the water phase in gas–water flow using an electromagnetic flowmeter (EMF) and rotating electric field conductance sensors (REFCSs) is introduced in this paper. An electromagnetic flowmeter instrument factor model is built and the correlation between electromagnetic flowmeter output and gas holdup in different flow patterns are explored through vertical upward gas–water flow dynamic experiments in a pipe with an inner diameter (ID) of 20 mm. Water superficial velocity is predicted based on pattern identification among bubble, churn, and slug flows. The experimental results show that water superficial velocity can be predicted fairly accurately for bubble, churn, and slug flows with a water cut higher than 60% (absolute average percentage deviation and absolute average deviation are 4.1057% and 0.0281 m/s, respectively). The output of the electromagnetic flowmeter is unstable and invalid in slug flows with a water cut below 60% due to the non-conducting gas slug is almost filling the pipe. Therefore, the electromagnetic flowmeter is not preferred to be used in such conditions.

No abstract

Three types of rotating electric field conductance sensors (REFCSs) with four, six, and eight electrodes are designed and optimized in this paper to measure the water holdup of oil–gas–water three-phase flow in vertical upward 20 mm inner diameter pipe. The geometric parameters of the REFCSs are optimized using finite element method to access highly sensitive and homogeneous detection fields. The performance of the REFCSs in the water holdup measurement of three-phase flows is experimentally evaluated by generalizing the Maxwell equation. Based on the measured water holdup from the REFCSs, the slippage behaviors in oil–gas–water are uncovered and the superficial velocity of the water phase is determined. The results show that the REFCSs present a high resolution in the water holdup measurement. The REFCS with eight electrodes has better performance than those with four- and six-electrodes, which indicates that its configuration and geometric parameters are more suitable for vertical oil–gas–water three-phase flow measurement in 20 mm inner diameter pipe.