2D Numerical Study of Transient-Blockage Interaction in Pressurized Water Pipes

Partial blockages commonly exist in pressurized water conveying pipelines due to various physical, chemical, and biological processes. Blockages may reduce pipe diameters and increase pipe wall roughness, resulting in lower water carrying capacity, additional energy loss, and deterioration of water quality. Consequently, it is of great practical significance to develop an effective blockage detection method to mitigate/eliminate the impact of blockages on the water piping system. Many blockage detection methods have been developed, among which the transient-based method is thought to be promising because it has the desirable merits of high efficiency, low cost, and nondestructive applications. However, the current transient-based method can only deal with relatively simple situations, such as idealized and simplified uniform blockages in single pipeline, which still has a far distance for its applications to realistic water pipeline systems. Recently, the authors have investigated the influence of different non-uniform blockages on transient frequency responses, which provides substantial progress on the understanding of transient-blockage interactions. However, one major issue still remains unclear in current transient theory and practice: the multiple-dimensional effect of non-uniform and irregular blockages on transient wave behavior. This will be the main scope of this study.

This paper aims to investigate the 2D interaction of transient-blockage under different flow and system conditions, based on the commercial software platform – ANSYS Fluent. The numerical scheme of this software is firstly tested, calibrated and verified for its applicability of parameter settings and selection of different computational modes through the results comparison with benchmarks of classic waterhammer theory and laboratory experiments in the literature. The verified numerical model is then applied to various blockage situations with different configurations (shapes and sizes) in the typical Reservoir-Pipeline-Valve (RPV) system. Extensive results will be obtained from these planned numerical simulations, which will be analyzed and discussed for understanding and quantifying the physical mechanism and process of transient-blockage interaction. The achievement and finding of this study may be useful to further develop/extend current transient-based blockage detection method to more realistic water pipeline systems.