The effects of improvement of the main shaft on the operating conditions of the Agnew turbine

Agnew turbine is a 45° axial flow Kaplan type micro hydro. The turbine was designed by an ex-lecturer of the University of Glasgow, to operate without guide vanes. Later due to a joint research program between the Iranian Research Organization for Science and Technology (IROST) and the University of Glasgow it was developed to operate under low head and limited flow potentials in Iran. The original design of the main shaft of the turbine was supported by a bearing housing consisting of three bearings outside the main casing, leaving the rest of the shaft, hub and the runner without any supports inside the turbine .Later a suitable support near the runner and inside the casing was designed and installed. Standard turbine tests showed considerable improvements in operating characteristics of the turbine due to these design modifications. This paper presents details of these improvements and the related outcomes.