Low head hydropower:a performance improvement study for Archimedes Screw turbines using mathematical modelling

Kotronis, Ilias K. (2016) Low head hydropower:a performance improvement study for Archimedes Screw turbines using mathematical modelling. Masters thesis, UNSPECIFIED.

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Abstract

The aim of the present MSc by research is to study the low head hydro power technologies, focusing on the use of Archimedes Screw, as hydro turbine, for electricity production and suggest potential design improvements with proper use and installation guidelines, intending to increase the produced energy per annum. The novelty introduced by the present research is the development of a methodology for the overall estimation of the performance for a hydro power station using Archimedes Screw turbine by identifying the loss mechanisms and minimize the losses produced from each one. As improvement was considered not only the nominal efficiency increase, but also the increase of the efficiency in relatively high and low flows and the exploitation of an extended range of flow and head, aiming in any case to maximize the produced electricity. The method used was the estimation of the produced power and the power losses calculated by a mathematical model which was developed in Matlab, taking into consideration the geometrical values of the turbine, the flow, the water level upstream and downstream, the speed and the efficiency of the secondary devices (gearbox etc). A serious effort for a CFD simulation was made. Unfortunately, the large number of elements and the large simulation time made in combination with the limited available time and resources made impossible the extraction of any results. Since no test rig was available and also there was no time for significant experimental work during one year duration MSc, manufacture’s data for efficiency and hydrological conditions were used from a small hydro power station with Archimedes Screw turbine to be able to validate the model. The same station was used as a case study for this research, for which were suggested potential improvements. As a result, the estimated turbine’s efficiency curve has a percentage variation from the curve provided by the manufacturer between -5.65 % and 3.47 %, and the turbine’s power curve between -0.46 % and 7.59 %. As a conclusion, it seems that the model can predict the efficiency and power with an acceptable accuracy for a preliminary level study of such a turbine. In addition, the maximum efficiency of a well designed and installed Archimedes Screw turbine seems very promising. However, as a free surface device it has a number of parameters with effect in the creation of losses which are limited in the known impulse and reaction hydro turbines.

Item Type:
Thesis (Masters)
ID Code:
126562
Deposited By:
Deposited On:
27 Jul 2018 15:08
Refereed?:
No
Published?:
Published
Last Modified:
20 Oct 2020 23:37