Completion of one year of FranSed

The first year of FranSed has been successfully completed on 1 September 2019. The significant achievements:

WP 1:   LEAP software is being used for energy modeling. Some field visits of the small power plants affected by erosion were conducted. The idea was to focus on smaller turbines such that the new technology developed in the FranSed project can be implemented on these plants. Fewa HPP (4 x 0.25 MW) was found to be one of the feasible sites containing high head Francis turbines. Sediment samples from Jhimruk HPP were collected and mineral content analysis and particle size distribution for the plant was performed.  Eroded guide vane of Jhimruk HPP was analyzed using a 3D scanner.

Fig 1: Mineral content analysis of the sediments in Jhimruk

Publication related to WP 1:

R. Awal, P. Sapkota, S. Chitrakar, B.S. Thapa, H.P. Neopane and B. Thapa, ‘A General Review on Methods of Sediment Sampling and Mineral Content Analysis’, Journal of Physics, Conference Series, vol. 1266, 012005, 2019.

WP 2 :    Design methodology is based on the literature compiled in the compendium ‘High pressure hydraulic machinery’ available at Waterpower Laboratory, NTNU. With the available hydraulic parameters of the site, main dimensions have been calculated and MATLAB has been used as the design software. The main design philosophy for this task is to reduce sediment velocity over all components, so focus was on reducing relative velocity in the runner and absolute velocities elsewhere. Several parameters are available for changing to give the user full control in the design process. No. of streamlines on the runner and no. of points along the streamlines will determine the grid smoothness. Runner blades no. is left to choose for the designer. Shroud streamline is generated from a Bezier curve. Energy distribution curve is then generated with the lowest relative velocity in the runner. Optimization work is in progress.

Fig 2: Complete runner blades geometry and single blade including thickness

Publication related to WP 2:

N. Acharya, C. Trivedi, N. M. Wahl, S. Gautam, S. Chitrakar and O. G. Dahlhaug, ‘Numerical study of sediment erosion in guide vanes of a high head Francis turbine’, Journal of Physics, Conference Series, vol. 1266, 012004, 2019.

WP 3 :    Experiments have been conducted in high-speed pot tester® available at IIT Roorkee to generate extensive data on erosion wear under different controlled operating condition. The solid-liquid mixture was prepared using Indian standard sand (99.3% quartz) as erodent in tap water. Four different target materials, namely Aluminum alloy (AA-6063), brass, steel and turbine steel (CA6NM), were selected to investigate the effect of hardness and toughness. The hardness and toughness were determined by the micro-hardness tester and Charpy test, respectively. For selecting the particle size, samples were collected from tail pool of Bhilangana Hydropower plant and particle size distribution was analysed. A CCl code is being prepared using Fortran language to incorporate erosion model in ANSYS CFX for erosion modelling.

WP 4 :    Simplified 14 kW guide vane less turbine was designed for Dhamile khola power plant in Nepal. Design head for power plant is 16 m and discharge is 100 liters per second. Two different runners were manufactured using two different processes. One followed manufacturing by investment casting and other followed pressing the blades & welding them. Laboratory testing has just begun and some preliminary results has been obtained. 

Fig 5: Simplified 14 kW guide vane less Francis turbine rig

Successful Testing of a 14 kW simplified Francis turbine at TTL

Researchers have performed a successful testing of a 14 kW simplified Francis turbine at Turbine Testing Lab (TTL) at Kathmandu University on 27 August, 2019. The turbine has simplified design, no guide vanes, modified stay vanes and trapezoidal spiral casing. The spiral casing was also designed in TTL by using proven analytical and state-of-the-art numerical methods under Master thesis of one of the researchers at TTL, Mr. Dadiram Dahal. According to the source, the output power surpassed 13 kW and the efficiency was almost 80%. As the turbine has been designed with simplified approach and for small power plants, this is one of the biggest milestones achieved by TTL til date.

              Source : TTL, KU

The manufacture of such turbine in Nepal is the first step towards development of Francis turbine with larger capacity in Nepal in future. The researchers hope that hydropower industries in Nepal will be able to implement this technology in near future. This turbine is best suited for micro to mini hydropower applications. However, research is on-going for implementing these turbines for larger power plants with variable speed generators under FranSed project.

The next step of implementation of the developed turbine in power plant has already started as MoU has been signed between Kathmandu University (KU) - TTL and Chauri Khola II Micro Hydro Project (CKMHP) for cooperation to facilitate research in turbine technology in Nepal and upgrade the production of power at Chauri Khola Micro Hydro Project by introducing Francis turbine designed at KU and manufactured by a local turbine manufacturer.

Source : TTL, KU

CONGRATULATIONS!!