water head
Recently Published Documents


TOTAL DOCUMENTS

208
(FIVE YEARS 67)

H-INDEX

15
(FIVE YEARS 3)

Author(s):  
Cafer Gencoglan ◽  
Serpil Gençoğlan

The aim of this study is to model the system that measures soil hydraulic conductivity using Programmable Logic Control (PLC), pressure transducer and motor pump in workshop conditions. In the study, a plastic pipe with a length of 2 m and a diameter of 100 was prepared to simulate an auger hole. In addition, a set was created using PLC and its module. In the hydraulic conductivity measurement system, the auger hole method (the bottom of the auger hole is above the impermeable layer) is used. Using the auger-hole equation, the system’s program was written in CODESYS-ST language and uploaded to the PLC. As a result of the regression analysis between the water head in the pipe (auger-hole) measured by hand (ESY) and PLC (PLCSY), an equation as PLCSY = 0,99ESY + 1,69 (R² = 1) was obtained and the Mean Absolute Percent Error (MAPE) of these two data sets was calculated as 0,41%. Each hydraulic conductivity measurement time is approximately 5, 6 and 8 minutes when the valve is fully open and half open and one-third open. The distance from the pipe base to the static level (d, cm) was measured as averages of 122.83, 123.91 and 123.7 cm on, respectively. In the first quarter section, the average times taken for the water level to rise from 20 to 25, 25 to 30, 30 to 35 and 35 to 40 was determined as 4.4, 6.0 and 26.1 seconds, respectively. The hydraulic conductivity values were calculated as 18.6, 13.2 and 3.1 cm/hour at the valve openings, respectively. The measured data is saved on an SD card. All of these processes are done automatically. The expectation that this system will measure hydraulic conductivity accurately, economically and quickly in field conditions is high and should be tested in field conditions.


2021 ◽  
Author(s):  
Diplina Paul ◽  
Abhisek Banerjee

Abstract The world’s population is going to surge past 10 billion by 2050. In order to cater to the energy demand of the ever-increasing posterity, scientists across the globe are working to harness power from renewable sources of energy. In pursuit of studying alternative energy sources, Savonius-style turbines (SSTs) have gained increased attention in the past few years. However, considering the low operational efficiency, design aspects of these turbines need to be improved. In this study, experimental investigations have been carried out using two designs of SSTs namely classical SST and elliptic shaped SST. The study has been carried out using an experimental setup that could produce a low head of < 1 m and water flow velocity within a range of 0.4 m/s to 1.2 m/s; the velocities at which perennial rivers flow. This study presents the comparison and analysis of the coefficients of power and torque measurements at various tip speed ratios. The study shows that there exists a local maximum when coefficient of performance is plotted with TSR. Out of the two profiles studied here, elliptic shaped SST generated a coefficient of power of 0.392 and a coefficient of torque of 0.538, when the water head was set at 1 m and flow velocity of 0.47 m/s. Experimental data reported here exhibit a gain of 16 % using an elliptic shaped SST over classical design.


Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7961
Author(s):  
Piyawat Sritram ◽  
Ratchaphon Suntivarakorn

In this research paper, the relationship between a crossflow turbine and propeller turbine size changes and the pond size in a free vortex power generation system was investigated. This relationship can be written in the form of a new mathematical equation using the principles of the response surface methodology (RSM) method. This study aimed to compare the efficiency of a crossflow turbine and propeller turbine to enhance a micro power plant from free vortex. The pond size in a micro power plant from free vortex was 1 m in diameter and 0.5 m in height with a 0.2 m outlet drain at the bottom. All turbines were tested at different water flowrates of 0.2, 0.3, 0.4, 0.5, and 0.6 m3/s to identify the rpm, water head, voltage, and electric current to access the waterpower, power output, and overall efficiency. At a 0.02 m3/s water flowrate, the crossflow turbine had greater overall efficiency than the propeller turbine, reaching 9.09% efficiency. From the comparison of the results of the two turbines used in the 0.5 m high cylinder-shaped generator pond, the turbine type, turbine size (height and diameter), number of blades, and water flowrate are key factors that affect the overall efficiency. The crossflow turbine can achieve greater efficiency than the propeller turbine in this generator system.


Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3161
Author(s):  
Alissa Vera ◽  
Edwin Pino-Vargas ◽  
Mahendra P. Verma ◽  
Samuel Chucuya ◽  
Eduardo Chávarri ◽  
...  

The La Yarada aquifer is the primary water resource for municipal, irrigation, and industrial uses in the semi-arid Tacna, Peru. Presently, over-pumping has caused severe groundwater management problems, including the abandonment of saline water wells. This study presents multivariate analysis and chemical–isotopic trends in water to investigate seawater intrusion and hydrogeological processes affecting water quality. The chemical and isotopic analysis of water samples, collected in two campaigns in the dry (August 2020) and wet (November 2020) seasons, together with the 1988 data, were evaluated with a mixing model, cluster, and factor analysis. The hydrochemical and isotopic mixing model suggested the formation of a wedge with 20% seawater intrusion. The heterogeneity of piezometric map isolines corroborates the wedge formation associated with the groundwater movement. The spatial distributions of factors, FA1 and FA2, suggest two processes of seawater front movement: dispersion (diffusion) of chemical elements and different types of water mixing, respectively. At the edge of the La Yarada aquifer, the water head was relatively low, permitting seawater and freshwater mixing. On the other hand, along the sea-land boundary, the water head of the La Yarada aquifer was relatively high, avoiding seawater and freshwater mixing; however, the chemical species were migrating from the seawater to the groundwater due to the diffusion processes. The cluster 4 samples are in the region corresponding to the isotopic mixing process represented by the FA2, while cluster 4 describes the chemical diffusion process represented by the FA2. Thus, the integrated approach is helpful to assess the seawater intrusion mechanisms in coastal aquifers in a semi-arid region.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Chun-bo Yang ◽  
Yuan Wang ◽  
Lin-bing Wang ◽  
Jing-qi Huang ◽  
Qing-wen Li ◽  
...  

Slotted tube drainage system plays an important role in reducing the wetting line of tailing dam. In the past studies, the permeability coefficient of geotextile was measured separately based on one-dimensional test, and the permeability characteristics of the whole system of the slotted tube overlay geotextile were rarely studied. Firstly, a set of radial flow test equipment for infiltration system of the slotted tube overlay geotextile is developed in this study. Then, with the aid of the test device, a two-dimensional radial flow test is conducted to investigate the drainage system of the slotted tube overlay geotextile before and after blocking by tailing sands, with considering different water head difference and the number of geotextile layers. By the two-dimensional radial flow test, it can be concluded that (1) the permeability coefficients of the slotted tube overlay geotextile before and after blocking all have a slight upward trend with the increase of water head difference; (2) with increasing the number of geotextile layers, the permeability coefficients before and after blocking increase first and then decrease, which approaching its minimum value at about two layers; (3) under the seepage pressure, some particles might attach to or stay in geotextile. Therefore, the permeability coefficient of the slotted tube overlay geotextile after blocking is significantly smaller than that before blocking. This study offers the insight to the further research on the permeation characteristics of the slotted tube overlay geotextile system.


Author(s):  
Congmin Liu ◽  
Chengzhong Pan ◽  
Chunlei Liu ◽  
Yuanzheng Zhai ◽  
Wanlai Xue

Ephemeral rivers commonly occur in regions with a shortage of water resources, and their channel configuration tends to change substantially owing to cultivation, tree planting and sand extraction. There is an urgent need to restore degraded river ecosystems. During short-term water conveyance, water storage in sand pits and leakage in dry riverbeds retards the flow of water, which is detrimental for ecological restoration of the riparian zone. A coupled dynamic leakage loss and flood routing model was established to predict the flow processes in the complex river channel of the Yongding River in China. The model mainly included three sub-models of flow dynamics, dynamic leakage loss, and water balance along multiple cross sections of the river channel. The complex section is reflected in the different infiltration properties for each section, and the existence of sand pits. The water head was dominated by flow velocity and the overflow from sand pits. Owing to the difference in landforms and the deposited sediment size of the riverbed bottom, the river channel was divided into 11 cross sections and a sand pit to ascertain the respective infiltration or leakage loss processes. The input parameters of the model came from field surveys of sand pits, river geometry and hydrogeology. The model was also calibrated and validated using monitoring data from ecological water releases into the Yongding River in 2019 and 2020. This coupled model can predict the water leakage loss and flow process of the water head and also provide important guidance for river reconstruction and ecological restoration.


2021 ◽  
Vol 15 (3) ◽  
pp. 8356-8363
Author(s):  
Nurul Ashikin Mohd Rais ◽  
M. F. Basar

This paper presents a parametric analysis of the outward flow reaction type turbine known as a Z-Blade turbine for low-head low-flow conditions. By applying the principles of mass conservation, momentum and energy, a nomogram was designed to investigate the theoretical performance characteristics. Based on the parametric analysis and the governing equations and experimental results, attempts have been made to prove that the mass flow rate, angular speed, centrifugal head, power output and efficiency respond dynamically to the water head, radius of the rotor, size of the PVC pipes and the nozzle exit area. A turbine with a 1” pipe diameter gives a higher performance compared to a 1/2” pipe diameter, and certainly the performances of both pipe sizes are improved when the supplied potential energy is increased. This innovative turbine has a maximum rotational speed at an optimum turbine diameter at 0.6m, accompanied by a point where there is a sudden reduction in the water flow rate, where previously the increment in the water flow rate was very high. This can shows from the outcome nomogram with 1” pipe diameter can perform 350 rpm speed with 1.48 L/sec water flow. The Z-Blade turbine has been examined and has shown good potential to be used for low-head (3m, 4m and 5m) and low-flow (less than 2.5 L/sec) conditions.


Water Policy ◽  
2021 ◽  
Author(s):  
Tingen Zhu ◽  
Wenping Li ◽  
Weichi Chen

Abstract A study on the risk of Cretaceous water inrush in the Ordos Basin in China is of great significance to the safe production and environmental protection of the western coal seam. This paper selects the following five key influencing factors for Cretaceous water inrush: the coal seam mining thickness, rock quality designation, distance between the top boundary of the water-conducting fracture zone and the bottom boundary of the Cretaceous system, the thickness of the Cretaceous aquifer, and the height of the water head. Furthermore, based on an analysis of geological and hydrogeological conditions of the Yingpanhao coal mine, the comprehensive weights of these factors were found using a fuzzy analytic hierarchy process and the entropy method (FAHP-EM) to be 0.27, 0.25, 0.22, 0.08, and 0.18, respectively. This paper describes the use of ArcGIS's spatial overlay analysis to create a risk assessment zoning map using these weightings. By comparing the evaluation results of the FAHP-EM and the water inrush coefficient method, it is shown that the FAHP-EM provides additional insight in assessing the risk of coal seam roof water inrush. The research results of this paper provide a theoretical basis for coal mining safety in western China to assess water inrush.


Sign in / Sign up

Export Citation Format

Share Document