MS Candidate
Nischal Pokharel (nischal.pokharel@ku.edu.np)
Supervisors / Advisors
Prof. Bhola Thapa
Dr. Biraj Singh Thapa
Objectives
1) Identify a suitable pump for laboratory testing in Turbine mode.
2) Numerical and experimental analysis of pump in Turbine mode and its design modification for better efficiency.
3) Modification and laboratory testing of pump impeller in Turbine mode
Summary
Pumps are the mechanical device to increase the pressure energy of liquid. Mostly they are used for raising fluids from lower level to higher level. In today’s world pumps occupy their positions in large application areas. It may be in different industries, water distribution system, sewage management, irrigation, hydropower and various other application areas. In context of Nepal, we can find plenty of pumps being used in various such areas nowadays. These pumps are completely imported from foreign country. Till date existing industries in Nepal, are quite unaware of its manufacturing prospect in Nepal utilizing its existing market in country. Although having long history of using them, no such research has been done in the field of pump in Nepal for local manufacturing too.
Experiments have shown that in relatively low power outputs, pumps with high technological standards in reverse operation can compete with conventional turbines in respect to maximum efficiency. This could be very advantageous in country like Nepal, because the cost for producing turbine is very high in comparison to cost of pump available in market.
This research focuses on use of pump as turbine for micro hydro plants. In this research the existing pump will be tested on turbine mode. Further optimization will be done to improve efficiency.
The research has been started market of pumps in Nepal. As per government around 3.5 billion of pumps has been imported in last fiscal year. The data also says that market of centrifugal pump is large than other pumps. As centrifugal pump is mostly suitable in turbine mode, the outcome of this research will be focused in utilizing such centrifugal pump in turbine mode.
Secondly during course of study, the existing problem in pump was studied with some case study. In Nepal, the existing pumps in different irrigation projects faced erosion problem. Similarly in some industries like paper mill, the impeller faces erosion and cavitation too. These examples says that in spite of such market of pumps, there equal challenge in their operation, which could another topic of research.
As the objective of project is to find suitable pump in turbine mode, the experimental set up has been started to test the pump in turbine mode. The centrifugal pump of 3kW capacity available at Turbine testing, has been used to study the behavior of pump in both turbine mode. Centrifugal pump existing in turbine testing lab is tested both in turbine mode and pump mode. The maximum efficiency of pump was obtained 57% in direct mode and 40% in reverse mode. The experimental set up was not so well instrumented and calibrated to gain accurate data. Further works is remaining in this part.
Lastly modeling of pump impeller has been completed using reverse engineering from existing pump impeller. Some basic CFD has been completed in pump impeller. The efficiency of pump has been found as 70% at design head and flow. The same impeller was 3 D printed, to find out its manufacturing aspects.