IJSRP, Volume 4, Issue 7, July 2014 Edition [ISSN 2250-3153]
Niroj Maharjan, Sailesh Chitrakar and Ravi Koirala
Most hydropower plants in Nepal are run-off type, which cannot supply the designed amount of energy during dry season and peak demand period resulting in energy crisis. Therefore, pumped storage plants can be an ideal solution to meet the current energy needs of the country. Most of these storage plants make use of a single unit acting both as turbine as well as pump; hence aptly called Reversible Pump Turbine (RPT). This paper explains the new application concept for use of such RPTs as auxiliary unit to supplement the main power unit in hydropower plants of Nepal. It also summarizes the design process of such runner with reference to the parameters available at Chilime region in central part of Nepal. The design is performed in two steps. The first step is an analytical design, which gives an initial geometry of the RPT runner. The process resulted in a runner of larger size than a normal Francis runner for same parameters since it has to work as pump as well. The next step is an optimization procedure involving CFD analysis under which the simulation of the RPT in turbine mode yielded an efficiency of 88.71%. The detail laboratory experiments on a model RPT will be performed later to validate the results from CFD and determine the characteristics of the designed runner at different mode and operating conditions.