Numerical Investigation of Sediment Erosion in Francis Turbine using OpenFOAM

Objectives:
Primary Objective:
To develop a Francis turbine experiment test rig setup and the numerical model in OpenFOAM.

Secondary Objectives:
To study the effect of leakage flow vortex filament from the GV to the runner.
To compare the erosion pattern and erosion rate
obtained between the numerical analysis with the experimental study.

Expected Outcomes:
Sediment erosion in hydro-turbines poses a significant global challenge, especially in hydropower situated in regions characterized by steep terrain and young topography, such as the Himalayas, Andes, Alps, and Pacific ranges. Various researches are being conducted on the effects on these sediments in the turbines. This is one of the researches to study the effects of sediment erosion in guide vane and runner of the Francis turbine. The study revolves around the leakage flow from guide vane being one of the major causes of erosion in Francis turbine. The leakage flow disturbs the main flow in the guide vane channel, which causes swirl flow at the clearance gap. So, the generated leakage flow causes vortex entering the runner channel eventually causes erosion in the runner. This phenomenon needs to be studied properly to have a better understanding of its effect on the guide vane and runner. Past literatures study found that a
vortex filament developed due to mixing of leakage flow with the main flow is found to hit the hub at inlet which causes erosion at the GV’s CG and runner inlet. Acknowledging that, the research objectives focus on the impact of leakage flow at the guide vane and runner with respect to concentration, sediment size and discharge. Anticipated outcome of the research includes the state-of-art of the effects of sediment erosion causing secondary flow in guide vane and runner of Francis turbine in various literatures. The analysis of the leakage flow vortex from the guide vane and its effect on the runner. The development of an empirical relation for the erosion pattern and rate in the Francis turbine guide vane with respect to concentration, sediment size and discharge. The comparison of the erosion pattern and the erosion rate from the numerical and experimental investigation due to the leakage flow erosion also can be expected. In general, this study aspires to contribute a wide-range insights regarding erosion phenomena that extend beyond academics, informing practical applications in the design and maintenance practices of
the hydraulic machineries.

Supervisors from host and Partner Universities:

Prof. Bhola Thapa, PhD, Kathmandu University
Asst. Prof. Sailesh Chitrakar, PhD, Kathmandu University
Prof. Hari Prasad Neopane, PhD, Kathmandu University
Prof. Zhongdong Qian, PhD, Wuhan University
Assoc. Prof. Zhiwei Guo, PhD, Wuhan University

About Myself:
Hello, everyone. Greetings from Rakish Shrestha. I am a Masters by Research student at the Hydro-Himalaya project, Kathmandu University. I am always trying to discover myself in a new way by learning from others. I describe myself as an analytical and detail-oriented in nature who likes to have everything well-organized. I am a seeker of connections and a communicator of ideas with like-minded people.

I completed my Undergraduate from Kathmandu University with the major in Mechanical Engineering. During my Undergraduate years, I developed interests in Computational Fluid Dynamics (CFD), Hydraulic Machinery, Non-Destructive testing, Heat Transfer and many others. The projects and researches that I have been involved in mostly revolves around these topics such as sediment erosion analysis in turbines, fabrication of hydro-cyclone separation system and infrared technology to detect the sub-surface in hydro-electric penstock. Besides my studies, I have a hobby of watching and playing sports, knowing about the world history and politics, learning to play musical instruments and doing some art works in my free time.

I value myself as a steadfast companion, offering loyalty and support. Though sometimes
perceived as a reserved person, my heart opens up in the sanctuary of trusted connections. I am
Rakish, a graceful dancer in the dance of life.

Rakish Shrestha
Master by Research Student
2022 Batch
rakishshrestha74@gmail.com

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