Research on acoustic behaviors of water pipelines with guide vanes

In this paper, the pipeline with guide vanes was taken as the research object, the flow noise was studied based on the hybrid calculation method, then the acoustic-structure coupling method was introduced to study the vibration and radiation noise, and then explored the best position of the guide vanes. Based on the pipeline experimental platform and improved experimental methods, it was found that the guide vanes had a better noise reduction effect on the elbows; based on that, a simulation study was carried out on the elbow with guide vanes, and the mechanism of the guide vanes on the velocity field and pulsating pressure of the pipeline was explored. Finally, the noise reduction effect at different positions of the guide vanes under different flow speeds was studied. The results indicated that the guide vane at the middle of the elbow had the best effect on improving the flow field and reducing noise in the working conditions studied in this article, providing a calculation basis for the design of the guide vane.

An SEM-REM-Based Study on the Driving and Restraining Mechanisms and Potential of Reclaimed Water Utilization in China

In order to promote the efficient use of reclaimed water in China and make water resources allocation better structured, this paper analyzed the factors that drive and restrain the current utilization of reclaimed water and unveiled their correlation and hierarchy in a way to develop a non-recursive structural framework of what drives and restrain reclaimed water use. By structural equation modeling (SEM), the transmission path of affecting factors was identified, the contribution of the factors quantified, and key indicators for potential prediction selected. On that basis, a random-effects model (REM) was built to predict the potential availability of the country’s reclaimed water. Meanwhile, parametric confidence intervals at 10–90% quantile levels were described, given the uncertainty of REM parameters. The results showed that four indicators for potential prediction, namely the total amount of wastewater treated, the density of water pipelines in built-up areas, investment in facilities for reclaimed water treatment, and the processing of applications for water treatment patents, are intertwined with the utilization of reclaimed water. Overall, the REM for potential prediction produced more precise fitting results, with the most significant fitting error standing at 5.9%. Going ahead, China is set to maintain the rapid growth in reclaimed water use, and up to 13.7 billion cubic meters of reclaimed water is expected to be available by 2025. This will help better structure the urban water supply and render regional water recycling more efficient.

Study the causes of pitting corrosion in carbon steel water pipeline at the site of advanced chemical industries complex

There are many factors that affect the pitting corrosion of carbon steel (Q235A) some of them are related to the pipeline material such as material chemical composition specifications and other related to water specifications such as water temperature, pH of the water, and chemical and physical specification of water. In this study, the investigation was done for both water quality and materials of pipelines (Q235A), four samples from on a piece of same rolled sheet welded pipe(carbon steel (Q235A) were prepared and tested for chemicals composition, microstructure, roughness, and thickness, the test results shown that no difference observed for all results only on one sample have difference roughness value near to the welded joint, these test applied for 4 pieces took from one pipe to check the effect of rolling of these pipes that can cause dissimilarity .which enhance corrosion rates. Then the water quality was investigated for temperature 45C, pH equal to 9, chloride, TDS, and water pressure, the test result showed that the temperature of the water was 45 C pH 9 and contain chloride with a concentration quite enough to initiate pitting. From the collected data this study specified the causes of pitting corrosion in the studied area of water pipelines and summarized in the flowing, this pipelines exposed to high pressure than the required, and temperature of water reach over 45C in summer, and chloride iron have the main contribution on pitting corrosion of these pipes.

Geospatial modeling of water supply distribution system: A case study of Dehradun city, India

Water utilities form the core part of any urban infrastructure. A spatial database of water distribution system (WDS) for Dehradun city has been created in a geographic information system (GIS) environment, while drawing data inputs from diverse sources and water supply-demand gap analysis has been performed. Environmental Protection Agency Network (EPANET, 2.0) has been used to analyze the WDS to explore its reliability in current and future scenarios. Mapping of the existing 564 km long distribution network revealed that more than three-quarters of the system has outdated water pipelines. An accuracy of 93% for pipe diameter estimation has been obtained upon validation by ground penetrating radar (GPR) survey. Water supply-demand gap analysis confirmed that although Dehradun city has surplus supply, it suffers from scarcity, mainly due to the unsatisfactory condition of the existing WDS. Twenty-seven percent of the existing pipes are smaller than the prescribed standards; there is an undesirable practice of direct pumping of water from tube wells into the network and storage tanks are required for at least 29 locations in the network. A 24-hour extended period EPANET simulation helped to identify the areas where water supply network experienced very low or negative pressure.

Economic Feasibility Analysis Development of Intake and Raw Water Pipelines in Kota Bangun Sub-District, Indonesia

Increasing the population in Kota Bangun Sub-District, Kutai Kartanegara Regency, in line with the consequence that growing needs for drinking water and raw water for local communities become a top priority. Public complaints about the increasing difficulty of obtaining clean water seem to be an obstacle that the Regional Government has yet to resolve fully. The production capacity of PDAM Kota Bangun is currently only 30 liters/sec, which is far from sufficient for the needs of all people in the Kota Bangun Sub-District. Economic feasibility calculation analysis utilized the NPV, IRR, and BCR methods and sensitivity analysis to obtain the economic feasibility for the value of developing intake and raw water networks. The results indicate, with a reasonable life condition of 30 years, the construction of water networks in Kota Bangun is still economically feasible. Reasonable with the minimum requirement of BCR = 1, with sensitivity analysis on two scenarios, considerations of 30% and 20% leakage, and 30.55% and 25% administrative costs. The results of the research show that IRR = 17.70%. If the analysis conditions are that investment costs increase by 10% with Fixed Benefits, the payback period is 6.8 years.

Impact of 2016 intense drought to small tropical reservoir: An early onset and late recovery experience in Timah Tasoh, Malaysia

This study investigates the hydrological drought impact during the extreme 2016 El-Nino to small tropical reservoir of Timah Tasoh, in Perlis, Malaysia. Small tropical reservoirs are important freshwater supplier due to its economic & strategic factors including (i) closer distance to inhabitants and agriculture footprints, (ii) easy access to the resource, and (iii) cheaper cost of water pipelines system. In theory, small tropical lakes or reservoirs are facing higher risk to drought compared to the bigger ones. However, detail information and evidence are required for site specific drought adaptation in the future especially the onset and offset of the drought at specific hydrometeorological and dam scale. Prior to that, a case study was conducted in one of the small-sized and shallow reservoirs of Timah Tasoh, Perlis to analyze the impact. The larger Pedu reservoir was selected as control site. Both reservoirs were having identical hydro-climatic characteristics (seasonality of rainfall). The observation on the rainfall and reservoir level data indicated that the small sized reservoir (Timah Tasoh) tends to dry about 2 months faster (reached dam critical level) and recover 1 month late compared to the normal dry season. In comparison with the Pedu reservoir, the drought onset and offset in Timah Tasoh was earlier and late respectively although the rainfall pattern is typical. The total impacted drying days for Timah Tasoh is 197 days compared to 78 days of Pedu (about 3 months longer). The findings indicate that the 2016 extreme drought impacted the Timah Tasoh small reservoir where they would suffer longer dry season and experienced slower recovery compared to the bigger Pedu reservoir. The outcome of this investigation signifies that the early drought onset monitoring should be implemented for the small sized reservoirs to take appropriate mitigation and preventive measures in adapting to the intense drought.