This study investigates the fluid flow through the runner of an exceptionally low specific speed Francis’ turbine using computational fluid dynamics (CFD) to predict some performance characteristic of the runner, and to determine the effect of cavitation on the flow features within the turbine. It employs FLUENT CFD codes for the analysis. The study was carried out under steady conditions in two- dimensional analysis, primarily using the RNG k-ε turbulence model. It is mainly on single phase analysis; however a single case of two-phase cavitation modeling was performed in order to evaluate cavitation effects. The hydraulic losses were much dependent on the inlet flow velocity and less dependent on the rotational speed. Cavitation occurred throughout the flow domain and this led to non-physical negative pressure predictions for the single phase analysis. For a fixed discharge, cavitation had significant effect on the prediction of the torque and hence the runner efficiency obtained from the CFD analysis. It causes a significant reduction of the runner efficiency by increasing the hydraulic losses and should be considered in the analysis of the flow features within a runner which is likely to experiences cavitation in order to overcome some of the shortcomings of the single phase predictions.


School of Sciences and Engineering


Mechanical Engineering Department

Degree Name

MS in Mechanical Engineering

Date of Award

Spring 6-1-2008

Online Submission Date


First Advisor

Serag El Din, Amr

Committee Member 1

Ashraf Sabry

Committee Member 2

Lamyaa El-Gabry

Committee Member 3

Mustapha Rizk

Document Type



107 p.


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Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.