Comparison between Hazen-Williams and Darcy-Weisbach equations to calculate head loss through conveyancing treated wastewater in Kerbala city, Iraq

Abstract

Reuse of wastewater has been widespread in this era to support the water sustainability process. Therefore, treated wastewater should be conveyed to suitable places and adopted for different uses. This study presents an empirical relationship between the Darcy-Weisbach and Hazen-Williams equations for four types of pipe material (ductile iron, GRP, concrete, and plastic) by using WaterCAD Version 8i. Two hydraulic models were developed to estimate the head loss in pipes by using different diameters: first, using pipe diameters from 800 mm to 1,200 mm for a flow rate of 1.16 m3/s, second, adopting pipe diameter from 1,600 mm to 2,000 mm for a flow rate of 4.63 m3/s. The study results are the head loss values obtained from the Darcy-Weisbach and Hazen-Williams equations, which were used to correlate them using IBM SPSS Statistics. The correlation coefficient between both equations turned out to be 0.991, 0.990, 0.990, and 0.990 for ductile iron, GRP, concrete, and plastic pipe materials. Additionally, the relationship between head loss and pipe diameter is negatively proportioned for both equations. Also, both head loss equation results are the same. The head loss values in the Darcy’s equation were higher for ductile iron and GRP materials, while being lower for concrete and plastic materials for both models. Selecting concrete or plastic pipes to convey treated wastewater is better than other pipe materials. Another conclusion is that the pipe diameter affects the head loss magnitude irrespective of the kind of equation whether Darcy-Weisbach or Hazen-William equation. Finally, this relationship is very useful for designers in converting the head loss values obtained using these equations.

Factor de fricción para tuberías de PVC y PE para riego

“…Analizando las pérdidas de carga teniendo como base DW -CW, para PVC se determinó: i) que la ecuación 11 presentó un error relativo (positivo) promedio del 0.24 % y es estable para los diámetros A pesar de que las ecuaciones 15 y 16 fueron desarrolladas para riego por aspersión y goteo, en donde se utilizan tuberías de PVC y mangueras de polietileno (Allen, 1986;Keller & Bliesner, 1990), estas presentaron una precisión menor con relación a las pérdidas de carga determinadas con las ecuaciones 11 (f PVC) y 12 (f PE). La ecuación de Hazen -Williams presenta la menor precisión de las ecuaciones analizadas (Tablas 2 y 3) debido a que utiliza un coeficiente constante para todos los diámetros y caudales (Abdulameer, 2022).…”

“…En una red de tuberías para riego, la velocidad mínima del agua es 0.6 m s -1 para garantizar el arrastre de los sólidos en suspensión y el aire que el agua contiene en emulsión y, la velocidad máxima de 1.8 m s -1 para reducir los efectos negativos que produce la sobrepresión generada por el golpe de ariete, aun cuando, hidráulicamente se puede transportar el agua con velocidades máximas de 3.0 m s -1 (Plastro, 1998;Ortiz, 2021), bajo estos criterios de velocidad, el flujo en las redes de tuberías presurizadas para riego es turbulento, por tanto, la ecuación Colebrook -White es la recomendada para estimar el factor de fricción (Praks & Brkic, 2018;Abdulameer et al, 2022).…”

Technical and technological Solutions for environmentally safe Irrigation with wide-reach Sprinklers

“…Studies of scientists [1][2][3][4][5][6][7][8][9][10] have established that the average intensity of rain at the beginning of the DM "Frigate" varies from 0.05 to 0.10 mm/min and reaches 0.45 mm/min at the end of the car when calm and increases to 0.6...0.8 mm/min with wind. The average actual rain intensity varies along the pipeline from 1.5 to 2.6 mm/min.…”

“…The average diameter of the droplets increases with distance from the fixed support from 0.2 to 2.8 mm [1][2][3][4][5][6][7]. Almost 70% of the irrigation norm is formed by drops of 0.8...2.0 mm.…”

“…They form a fine-drop rain with a small height of the rain cloud rise. The radius of capture by rain reaches 6-18 meters, with an average intensity of 0.3-0.8 mm/min [1][2][3][4].…”