Abstract
Free-stream turbine is an alternative to classical high-head turbines. On one hand, it produces less power, on the other hand, it requires less ser-vice and construction and might be an eco-friendlier option. We have modelled the start-up of a free-stream turbine, which consists of a wheel and a generator, using CFD methods. Unsteady RANS method with k-ω SST model was employed to describe turbulence. We have used finite-volume solver Ansys FLUENT on unstructured mesh. Moving mesh approach was applied for the wheel rotation. We have based the blade sys-tem design on several simple assumptions. Wheel inertia and generator load were taken into account through simple moment equations. Velocity fields during different moments of time were obtained. We have obtained both momentum and power of the wheel curves over time and reviewed cases with generator presence and absence. Angular velocity curves comparison over time is presented for two cases.
Highlights
Polytechnic University is known for it’s turbomachinery researches [1,2,3].More than 60% of electricity power in Russia is produced by thermal power station, according to report from UES of Russia
One can obtain difference formula for wheel angular velocity which depends on flow parameters: first order
We will analyze the computation of wheel motion without external load
Summary
Polytechnic University is known for it’s turbomachinery researches [1,2,3].More than 60% of electricity power in Russia is produced by thermal power station, according to report from UES of Russia. Climate conditions wouldn’t allow to construct solar and wind power stations all over the country, so hydro power plants seem to be most reliable “green” option. Computational fluid dynamics is the most convenient method for studying behavior of rotating machinery from hydropower turbines to wind turbines [9,10,11]. This method is applicable for free-stream hydropower stations. Most of CFD papers aims to describe one or several working regimes 12-13] This leads to stationary methods usage and doesn’t allow to take transitional effects into consideration. Blade leading edge angle and trailing edge angle were built according to non-separated flow condition and necessary swirl value.
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