Modelling of Air Pocket Entrapment during Pipe Filling in Intermittent Water Supply Systems

[EN] Intermittent water supply (IWS) operations frequently involve water filling and emptying cycles that are strongly influenced by air-water interaction. Storm Water Management Model (SWMM) software has been recently proposed to simulate pipe filling events in IWS systems. As the tool is conceived to simulate both free surface and pressurized flows, it also has the potential to analyse the air entrapment. However, there is no numerical model capable of accurately and efficiently simulating the air behaviour during these events, nor of predicting the locations of air pockets created during the pipe filling process.An experimental pipe rig was assembled to better understand the pipe filling process in terms of pressure variation, the propagation of the filling wave and the air entrapment locations under different initial conditions. The pipe rig has a classic reservoir-pipe-valve configuration. Different behaviours are observed in this experimental setup during the pipe filling tests. An entrapped air pocket is created at the high point for lower flow rates, which is not dragged when the pipe is full. This air pocket can go from a similarly free surface flow inside the pipe to a complete water filled flow, depending on the flow rate. For low flow rates, a high head loss is introduced due to a hydraulic jump inside the pipe. For higher flow rates, the air is dragged, no air is entrapped and only the local head losses from the change of direction at the high point are observable.Following the collected experimental data, SWMM is used to assess to which extent it can predict entrapped air pockets location and their volume. Different filling processes can occur and an air model should be included to simulate the tests carried out in the pipe rig. The results obtained show that SWMM is capable of predicting air pocket locations but not the air pocket volumes. Further research is necessary to improve SWMM in this context.Ferreira, J.; Ferras, D.; Covas, D.; Kapelan, Z. (2024). Modelling of Air Pocket Entrapment during Pipe Filling in Intermittent Water Supply Systems. Editorial Universitat Politècnica de València. https://doi.org/10.4995/WDSA-CCWI2022.2022.1411

Does stirring influence hydrothermal carbonization experiments? A laboratory and computational study of a lignocellulosic biomass

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Managing non-revenue water in Mwanza, Tanzania: A fast-growing sub-Saharan African city

This research articles was published in Journals Scientific African Volume 12,2021,High non-revenue water (NRW) and unreliable water supply services are major challenges in operations of the water infrastructure of most fast-growing cities in developing coun- tries. In this study, an analysis of the existing distribution network was carried out to investigate its performance concerning water loss reduction and system improvement. A high percentage of NRW (50%) was found in a selected district metering area (DMA) com- pared to the city’s entire network (37%). About 87% of the NRW was contributed by real losses in the DMA, while about 52% of the nodal junctions had pressure above the recom- mended thresholds. The high pressure was responsible for the observed leakages and pipe bursts in the DMA. Optimization of pressure by using pressure-reducing valves as well as changing the network topology minimized the potential leakages to 46%. Also, flow veloci- ties in about 83% of the pipes were found inadequate leading to poor water quality due to water stagnation. Low velocities were due to oversized indicating incidence of unplanned spatial and temporal expansion of the distribution network. This study, therefore, revealed that a comprehensive zone by zone assessment of water distribution network can improve the management of non-revenue in unplanned urban areas which is in line with ensuring the availability and sustainable management of water and sanitation for all

Mutations in KEOPS-Complex Genes Cause Nephrotic Syndrome with Primary Microcephaly

Galloway-Mowat syndrome (GAMOS) is an autosomal-recessive disease characterized by the combination of early-onset nephrotic syndrome (SRNS) and microcephaly with brain anomalies. Here we identified recessive mutations in OSGEP, TP53RK, TPRKB, and LAGE3, genes encoding the four subunits of the KEOPS complex, in 37 individuals from 32 families with GAMOS. CRISPR-Cas9 knockout in zebrafish and mice recapitulated the human phenotype of primary microcephaly and resulted in early lethality. Knockdown of OSGEP, TP53RK, or TPRKB inhibited cell proliferation, which human mutations did not rescue. Furthermore, knockdown of these genes impaired protein translation, caused endoplasmic reticulum stress, activated DNA-damage-response signaling, and ultimately induced apoptosis. Knockdown of OSGEP or TP53RK induced defects in the actin cytoskeleton and decreased the migration rate of human podocytes, an established intermediate phenotype of SRNS. We thus identified four new monogenic causes of GAMOS, describe a link between KEOPS function and human disease, and delineate potential pathogenic mechanisms

Potential Micro-Hydropower Generation in Community-Owned Rural Water Supply Networks in Ireland

The potential of micro-hydropower generation has been evaluated in seven community-owned rural water supply networks (CORWSN) in Ireland. The replacement of the existing infrastructure in place to reduce pressure in the networks with micro-hydropower turbines (Scenario 1) was considered. New potential locations for additional pressure reduction were also considered (Scenario 2). An assessment of the energy potential and economic viability of each site was carried out, including quantification of leakage reduction impacts. While only one of the seven CORWSNs showed two potential sites with power higher than 1 kW, the power generated can still have significant impacts on local energy demands. The estimated total energy saved in Scenario 2 ranged from 0.63 MWh year−1 to 84.5 MWh year−1 according to the micro-hydropower potential in each CORWSN. Furthermore, water savings from 4348 € m−3 to 73,264 € m−3 were estimated due to the reduction of leakage volume after installing micro-hydropower turbines at the potential sites detected in Scenario 2. Thus, the water cost saving associated to the reduction of leakage volume makes the incorporation of this element in the networks feasible

One-Dimensional Fluid–Structure Interaction Models in Pressurized Fluid-Filled Pipes: A Review

The present review paper aims at collecting and discussing the research work, numerical and experimental, carried out in the field of Fluid–Structure Interaction (FSI) in one-dimensional (1D) pressurized transient flow in the time-domain approach. Background theory and basic definitions are provided for the proper understanding of the assessed literature. A novel frame of reference is proposed for the classification of FSI models based on pipe degrees-of-freedom. Numerical research is organized according to this classification, while an extensive review on experimental research is presented by institution. Engineering applications of FSI models are described and historical accidents and post-accident analyses are documented

Equity analysis of intermittent water supply systems by means of EPA-SWMM

Intermittent water supply (IWS) is a frequent operation approach in developing countries. A number of factors contribute to IWS, such as leakage and water shortage, leading to inequitable water distribution. A way to reduce the inequity in IWS systems is by planning or adapting the network for equitable water distribution, which requires software capable of describing IWS conditions, including not only pressurized flow but also free-surface. In this paper, a new index for equity analysis is presented and compared with the existing indices available in scientific literature. The comparison is based on the EPA-SWMM modelling framework and standard IWS operations, including pipe emptying and filling, have been considered. Results reveal that EPA-SWMM has great potential in simulating IWS systems, especially in the application for equity analyses, as it provides a more realistic description of the pipe filling and emptying operations compared to standard water distribution modelling software. Furthermore, a novel equation called volumetric coefficient was developed which has a significant advantage in identifying the nodes with a higher impact on network equity, and ensuring the fair distribution of supply along the distribution network, considering the relevance of nodal demand, which none of the other indexes in the literature were addressed. HIGHLIGHTS A novel equation was developed for calculating the supply equity in the network, named volumetric coefficient (VC).; The findings indicate that the VC has an advantage over other equations found in recent literature, on the analysis of equity in intermittent supply.; Simulation of flow patterns in the network during filling and emptying operations was analysed using EPA-SWMM.