The summary of spanwise values and other blade parameters is provided in the Supplementary Material. The angle of deviation was calculated using Carter's parameter for the circular arc camber line ( Hothersall 2004). To incorporate the effect of the flow deviation, the angle of deviation was subtracted from the blade stagger angle. chord length of blade/blade pitch) at the hub of the runner was confined near 1 for minimum profile losses ( Chen & Engeda 2019). The velocity components and blade parameters, shown in Figure 4, were calculated for five spans distributed equally along the radius. So, to simplify the manufacturing process, blades were designed with circular arcs and a constant thickness. As long as the camber and twist of the blades are preserved, the performance of the propeller turbine does not vary significantly by using a constant thickness profile instead of an airfoil profile ( Demetriades et al. This paper is expected to (i) introduce the WTP technology to agriculture practitioners and infrastructure planners, (ii) provide a methodology of the hydraulic design of a WTP to engineers, and (iii) give a head start to the long-stagnant research and development of WTPs.Īfter calculating the sizing parameters, blades were designed. So, the main objective of this paper is to provide technical documentation on WTP technology. The research and development on this topic seem to have lagged significantly behind due to the takeover of fuel and electricity-based pumping systems.
However, the available literature and documentation on WTPs are insufficient to support the design decisions. Some products with higher head ratios of 8:1, 10:1, 12:1, 18:1, and 20:1 have also been reported which seems very promising ( Tsutsui 1990).
Series of models have ranged from 10 to 120 cm in rotor diameter and from 4:1 to 6:1 in head ratio. In some documents, they have been classified according to the diameter of the propeller and the ratio of the installation head to the delivery head (head ratio). However, more recent documents on this technology are missing. The history of WTPs can be traced back to the 1920s when they were reported to be in use specifically in China where, by 1979, about 60,000 WTPs were irrigating 400,000 ha ( Fraenkel 1986). However, this infrastructure may not be economically viable for individual farmers and rather is recommended to be installed and operated by a community or a governing body. The WTP system requires much less civil works than expanding tertiary canal networks and can also work as an infrastructure for water supply in combination with a water treatment facility. So, as a better alternative for environment-friendly and inexpensive irrigation infrastructure, this paper proposes the design methodology of a community-operated hydro-powered pump called water turbine pump (WTP). In addition, the problems related to the distribution of power and fluctuating voltages in Nepal add to the ineffectiveness of the electrical pumping system ( Pande et al. They are also not an environment-friendly option, considering the emissions from fuels and the high energy intensity of electrical pumping.
However, these pumps turn out to be expensive for smallholders farmers in a long run because of the high operation and maintenance costs associated with each. Pumped irrigation is ruled by fuel-based and electrical pumps worldwide and the case of Nepal is no different. The WTP designed using this methodology could utilize a head of 3 m and a flow rate of 150 lps to deliver 14 lps of water to a height of 14.9 m, yielding a head ratio of 1:5, with an overall efficiency of 50.5%. With an objective to induce momentum in the research and development of this technology, this work presents a well-defined methodology to design a WTP using a propeller turbine directly coupled with a centrifugal pump, in reference to a site located in Bardiya, Nepal. Moreover, there are insufficient literature and technical documentation to support the design decisions for developers. Although introduced in the 1920s, this technology has been largely ignored nowadays. So, as a better alternative for environment-friendly and inexpensive irrigation infrastructure, this paper proposes a design methodology of a community-operated hydro-powered pump called water turbine pump (WTP). The problems related to the distribution of power and fluctuating voltages add to the ineffectiveness of the electrical pumping system. This has forced farmers to use fuel and electricity-based pumps, which are both expensive and unsustainable. The agriculture sector of Nepal has been plagued by problems of poor irrigation networks and infrastructure.