Frontiers in Heat and Mass Transfer (FHMT), 20, 8 (2023) DOI: 10.5098/hmt.20.8 Global Digital Central ISSN: 2151-8629 1 LAB-SCALE SYSTEM FOR SMALL RAM PUMP’S TESTING AND PERFORMANCE EVALUATION M. El-Bayoumi a,† , A. M. Abouel-Fotouh a , Amal El Berry a a Mechanical Engineering Department, National Research Centre (NRC), Giza, 12622, Egypt ABSTRACT Ram pumps employ renewable energy in the form of water head to pump water, but they have performance issues that require difficult on-site testing and tuning, hence limiting their application. The current research developed a low-cost lab-scale testing system for small ram pumps’ performance evaluation, tuning and leak testing. The developed system is made from available, low-cost, sensors and components. It conserves test water by setting the supply head through continuous circulation of water. The system was tested on a low-cost small sized ram pump, specially built using plumbing components. Test results demonstrated the capacity of the developed testing system. Keywords: Ram pump, performance test, flow rate measurement, supply head, leak test 1. INTRODUCTION Ram pumps use the potential energy of water flowing from springs, streams or rivers to lift a fraction of that water up to a higher level, compared to the head of supply water. This is achieved by means of water hammer action developed by sudden closure of a valve (ram pump’s impulse valve) that interrupts water flowing inside a pipe (ram pipe) from the supply (Abate and Botrel, 2002). The kinetic energy of the moving water trapped in the ram pipe is converted into a potential energy on the water delivery side. Ram pumps do not require any traditional energy source to operate (Yussupov et al., 2020), and they operate continuously with minimal need for maintenance. An installed ram pump delivers 1000 to 50000 liters of water a day to a reservoir of a village (Anonymous, 2007). Accordingly, ram pumps have the potential to solve problems of water supply shortage for households and agriculture in rural areas (Alkouhi and Lashkarara, 2017; Yussupov et al., 2022). Ram pumps suffer from sensitivity to running conditions and need for on-site testing. This is due to ram pumps output; the delivery head and flow rate, being function of a number of parameters. A ram pump’s performance is affected by the supply head, diameter and length of ram pipe, size and pressure of its air chamber, and diameter, mass and stroke length of its impulse valve’s disc. A number of researches were conducted to evaluate the interdependent effects of these parameters on the performance of a ram pump. Young (1998) formulated three non-dimensional parameters to define ram pump characteristics. These parameters are function of ram pump’s supply and delivery heads, flow rate and beating frequency of its impulse valve. The upper and lower bounds of these non- dimensional parameters would define the feasible area of ramp pump’s design. Salins et al. (2015) investigated the effect of ram pipe length on the delivered flow rate. They found a peak of delivered flow rate at 2 m ram pipe length. De Carvalho et al. (2016) studied the effect of air chamber’s size on the delivery flow rate at different delivery heads. Other studies investigated development of ram pump designs to increase its performance such as Yang et al. (2014) whom demonstrated that placing a diffuser before the impulse valve would increase delivered flow rate and the delivery head. A number of systems were developed, and reported in literature, for testing the performance of ram pumps. Alkouhi et al. (2019) presented a neat system, yet it has a room for development. Apparently, it would waste water and its falling output column would suffer from siphon effect and would need to have an opened top. Also, flow rates measuring technique is not described. The system reported by Mbiu et al. (2015) circulates water and employ reservoir and a tank for fixing the delivery head. However, it is a large system and they have not described their flow rates measuring technique. The system demonstrated by Asvapoositkul et al. (2019) is an easy to implement system, yet it would waste test water. Flow rate measuring technique and supply head fixation technique are not described. The current research aims at developing a lab-scale low cost system for small ram pumps testing, tuning and performance evaluation. This system would facilitate testing a ram pump at given running conditions. Objectives include developing a, simple to control, water supply source with the capacity to change the supply head, developing a variable delivery head arrangement and developing a ram pump output assessment system. The system would assess the pump’s performance parameters such as supplied and delivered water flow rates at different supply and delivery heads. For the purpose of testing the system’s capacity, a small 2” diameter ram pump was designed and built from specially selected plumbing components. 2. TESTING SYSTEM CONSTRUCTION The developed ram pump testing system consists of a tank, a basin, an electric pump, delivery head arrangement, electronic flow meters, pressure gauges, auxiliary valves, pipes, flow control valves and air trap, connected as shown in Fig. 1. 2.1 The Supply Tank The supply tank (T) of the system is a PVC tank of 200 liters, without cover. It is fitted with two ports; the first is a 2 inch diameter output port fitted with a ball valve, near its bottom to feed water to the ram pipe (RP). The second port is a 1 inch input port near tank’s top. This port is connected to reinforced hose H1 that feeds water to the supply tank during the runs to maintain its water level. Frontiers in Heat and Mass Transfer Available at www.ThermalFluidsCentral.org † Corresponding author, Email: el_bayoumi@hotmail.com