Experimental study of renewable hydro powered tyre piston pumps for water supply and a case for application of similitude theory

In this paper, the authors emphasize the need for a thorough investigation of relatively new hydro powered pumping technology, an inflating-deflating tyre-piston pump, with an objective to optimize and create a niche for this pump as a replacement to ram pump in certain operating range, which is disadvantaged from the impacts of water hammer on the life of impulse valve and drive pipe. The paper introduces a dimensional analysis based approach of similitude to identify the control variables and functionalities followed by intensive experiment. Two tyre-piston pumps for different piston diameters for the same tyre size are chosen for investigation. The study reveals that the drive flow and dynamic head at pump entry as two major variables which need to be optimised for achieving efficiencies comparable to ram pumps. The entire system being unsteady, the loss analysis remains a challenge. The study identifies a range of 2-15 L/s of drive flows and 1-5 m of drive head in which the efficiency of tyre-piston pumps needs to be optimized to 50-60% compared to the reported efficiency of 15-30% for the two pumps in this paper. Transient study using sophisticated instruments and CFD simulations are strongly recommended for future optimization study.