This paper investigates the thermal fluid-flow transport phenomena in an axially rotating passage in which twin concentric orifices of different radii are installed. Emphasis is placed on the effects of pipe rotation and orifice configuration on the flow and thermal fields, i.e. both the formation of vena contracta and the heattransfer performance behind each orifice. The governing equations ar...

The present paper demonstrates a proof-of-concept by introducing variable guide vane system in the draft tube of high-head Francis model turbine. aim is to examine hydraulic performance turbine while mitigating pressure pulsations tube. vanes can rotate about an axis up ±45°. mitigation studies were performed at lower- and upper-part loads. was examined all operating ranges within head. There s...

Hydropower plays a key role in the actual energy market due to its fast response and regulation capacity. In that way, hydraulic turbines are increasingly demanded to work at off-design conditions, where complex flow patterns and cavitation appear, especially in Francis turbines. The draft tube cavitation surge is a hydraulic phenomenon that appears in Francis turbines below and above its Best ...

The primary goal of this paper is to evaluate an innovative Z-Blade turbine technology and its potential implications for production costs manufacturing techniques. From literatures, conventional pico-hydro technologies with a capability less than 5kW are getting more attention as good alternatives environmentally friendly power generation, but there expensive complex small generation domestic ...

Computational fluid dynamic (CFD); Linearized two-dimensional transient flow (LTDT); Polar gridline transformation method. Abstract A novel derivation to transfer an actual domain with circular geometries to the computational domain, which is competent for application to computational fluid dynamics, is derived. Outcome formulas could be employed in cases of gridline transformation in the metho...

This paper investigates the application of a nonlinear controller to the multi-input multi-output model of a system consisting of a hydraulic turbine and a synchronous generator. The controller proposed is based on a feedback linearization scheme. Its main goal is to control the rotor angle as well as the terminal voltage, to improve the system's stability and damping properties under large dis...

Experimental tests in prototype are necessary to understand the dynamic behaviour of the machine during different operating points. Hydraulic phenomena as well as its effect on the structure need to be studied in order to avoid instabilities during operation and to extend the lifetime of the different components. For this purpose, a complete experimental study of a large Francis turbine prototy...

Turbine is the most critical component in hydropower plants because it affects the cost as well as overall performance of the plant. Hence, for the cost effective design of any hydropower project, it is very important to predict the hydraulic behavior and efficiency of hydro turbines before they are put in actual use. Experimental approach of predicting the performance of hydro turbine is costl...