A reference pelton turbine - design and efficiency measurements

Bjørn W Solemslie,Ole G Dahlhaug

doi:10.1088/1755-1315/22/1/012004

Abstract

The Pelton turbine has been subject to a varying degree of research interest since the debut of the technology over a century ago. Despite its age there are gaps in the knowledge concerning the flow mechanisms effecting the flow through the turbine. A Pelton turbine has been designed at the Waterpower Laboratory at NTNU. This has been done in connection to a Ph.D. project focusing on the flow in Pelton turbine buckets. The design of the turbine has been conducted using in-house knowledge in addition to some comments from a turbine producer. To describe the geometry multiple Bezier curves were used and the design strategy aimed to give a smooth and continuous gradient along the main flow directions in the bucket. The turbine has been designed for the operational conditions of the Pelton test rig installed at the Waterpower Laboratory which is a horizontal single jet test rig with a jet diameter(ds) of 35 mm. The diameter(D) of the runner was set to 513 mm and the width(W) of a bucket 114 mm, leading to a D/W ratio of 4.5. Manufacturing of the turbine has been carried out in aluminium and the turbine has undergone efficiency testing and visual inspection during operation at a head of 70 m. The turbine did not performed as expected and the maximum efficiency was found to be 77.75%. The low efficiency is mainly caused by a large amount of water leaving the bucket through the lip and hence transferring close to zero of its energy to the shaft. The reason for the large lip loss is discussed and two possible causes are found; the jet is located too close to the lip, and the inner surface of the bucket does not lead the water away from the lip. The turbine geometry and all data from both measurements and simulations will be available upon request in an effort to increase the amount of available data concerning Pelton turbines.

Highlights

In a time where the environmental crisis caused by human activity becomes more evident each year, the need for further development within renewable energy technology increases
The Intergovernmental Panel on Climate Change (IPCC) promotes a number of technologies as means to mitigate the effects of the climate change, one of which is hydro power [1]
The turbine design presented in this paper shows a low efficiency and the best point of efficiency is located at a much lower flow rate than the design flow

Summary

Introduction

In a time where the environmental crisis caused by human activity becomes more evident each year, the need for further development within renewable energy technology increases. The Intergovernmental Panel on Climate Change (IPCC) promotes a number of technologies as means to mitigate the effects of the climate change, one of which is hydro power [1]. Multiple types of hydro power turbines exists, and this paper will focus on one of them; the Pelton turbine. The Pelton turbine is defined as an impulse turbine as it utilizes only the kinetic energy from the water as it passes through the turbine. The Pelton turbine operates in an open housing and is usually installed in areas with a high head and a relatively low flow

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Discussion

Conclusion