CFD-Driven Valve Shape Optimization for Performance Improvement of a Micro Cross-Flow Turbine

Abstract

Abstract:Turbines are critical parts in hydropower facilities, and the cross-flow turbine is one of the widely applied turbine designs in small-and micro-hydro facilities. Cross-flow turbines are relatively simple, flexible and less expensive, compared to other conventional hydro-turbines. However, the power generation efficiency of cross-flow turbines is not yet well optimized compared to conventional hydro-turbines. In this article, a Computational Fluid Dynamics (CFD)-driven design optimization approach is applied to one of the critical parts of the turbine, the valve. The valve controls the fluid flow, as well as determines the velocity and pressure magnitudes of the fluid jet leaving the nozzle region in the turbine. The Non-Uniform Rational B-Spline (NURBS) function is employed to generate construction points for the valve profile curve. Control points from the function that are highly sensitive to the output power are selected as optimization parameters, leading to the generation of construction points. Metamodel-assisted and metaheuristic optimization tools are used in the optimization. Optimized turbine designs from both optimization methods outperformed the original design with regard to performance of the turbine. Moreover, the metamodel-assisted optimization approach reduced the computational cost, compared to its counterpart.

Numerical validation of a design methodology for cross-flow turbine type Michell-Banki

“…Open Access bajo la licencia CC BY-NC-SA 4.0 (https://creativecommons.org/licenses/by-nc-sa/4.0/) Contrary to the different optimization approaches both numerical and experimental performed in the last decades (Olade, 1987), the design methodologies of the MBT must be updated (Tesfaye-Woldemariam et al, 2018) since there are currently new material s wi t h better physical properties, equipment and manufacturing techniques that allow obtaining improved components. Thus, a good methodology design for sizing the MBT components will have a significant impact on the performance, which will increase its implementation feas ibil it y as a generation technology for appropriate site conditions (Q and H).…”

“…Since 2015, hydroelectric energy constitutes about 61 % of total global renewable energy. From this, the small and microhydroelectric power plants contribute around 7 % (Tesfaye- Woldemariam, Lemu, & Wang, 2018). This technology offers a great exploitation potential as an energy generation alternative from unconventional sources of renewable energy, particularly in noninterconnected zones -NIZ-of developing countries, with reduced impact in the ecosystem, compared to the big hydroelectric power plants (Paish, 2002).…”

Optimization of the Efficiency of a Michell-Banki Turbine through the Variation of its Geometrical Parameters using a PSO Algorithm

“…In addition to their operating parameters, the geometric configuration of MBTs has been studied, adopting different methodologies, to improve their efficiency by varying the geometry of the nozzle, runner, and blades. Numerical (Computer Fluid Dynamics, CFD) and experimental simulations have been implemented to determine the influence of the geometric parameters of the nozzle and the runner on MBT efficiency; for example, when a guide vane is used, the performance of the nozzle changes [12], showing an improvement of 5.33%. Other authors have proposed the implementation of two nozzles in the turbine to enhance its efficiency [13] and presented mathematical formulations that can define the ideal curvature of the nozzle, specifically the back wall that redirects water to the runner, ensuring uniform velocity and angle of attack along the runner inlet.…”

Reinforcement T-Joint Design and Structural Validation for a Hydroelectric Power Plant: Study Case

“…1. Hydroelectric capacity set up in the world at the end of 2017 [1] The big hydroelectric power plants are shown as the main electric supply source, representing since 2015 54% of world renewable energy total capacity, establishing itself as one of the proven, predictable and most profitable sources of renewable energy [2][3][4][5][6].…”