Simplified Analysis and Design of the Hydraulic Ram Pump

Abstract

Hydraulic ram pumps are currently of interest because they make use of a renewable energy resource and are environmentally friendly. Ram pumps are particularly appropriate for use in the developing world as their construction is basic and robust and they are inexpensive and easy to install and maintain. Numerous attempts to analyse the complex behaviour of a ram pump system have been made in the past, but few have been successfully translated into simple design procedures and none have resulted in a general method for a ram pump of any size. The analytical approach adopted in the present paper assumes constant friction loss in the drive pipe during acceleration and concentrates on zero recoil conditions at which optimum pump performance occurs. Four simple and general design equations are derived which incorporate conservative assumptions for the critical velocity in the drive pipe and the effect of system losses. Design examples are given and design predictions compared with new and existing test results. Conclusions are drawn regarding the relevance of traditional drive pipe length–drive pipe diameter (L/D) and drive pipe length–supply head (L/H) ratios.