Keywords

Wind turbine, Computational Fluid Dynamics, stall

Start Date

25-6-2018 2:00 PM

End Date

25-6-2018 3:20 PM

Abstract

Utilising New Zealand’s winds for optimum power production for small-scale use requires a robust, efficient wind turbine. Thinair 102 is a one blade downwind stall-regulated turbine designed to maximise power in gusty winds. However, rapid variations in Tip Speed Ratio (TSR) due to wind speed can be detrimental to the turbine and controller from the changing blade stall fraction over very short time periods. In order to optimise future blade design and improve the response of the control system to such fluctuations in power output understanding stall on the blade is crucial. This research therefore predicts stall behaviour of the blade for a range of TSR using observational and simulation methods.

A turbine blade was instrumented with tufts attached to the blade and a camera mounted on the hub. Digital post processing output was a stall intensity map and the blade stall fraction. Additionally Computational Fluid Dynamics (CFD) and Blade Element Method simulations were computed for a range of TSR.

Three distinct regions of stall on the Thinair 102 blade at lower TSR were found from the observations and three-dimensional simulation results. The stall in the central part of the blade was found to have the most significant effect on the torque and thrust from the turbine. Predictions for power output at higher wind speeds changes with numerical method used. The stall fraction on the blade was observed to be periodic with decreasing amplitude over time due to the tower shadow effect as the blade path sweeps around.

Stream and Session

D1: Environmental Fluid Mechanics

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Jun 25th, 2:00 PM Jun 25th, 3:20 PM

Stall behaviour of the Thinair 102 single-bladed wind turbine

Utilising New Zealand’s winds for optimum power production for small-scale use requires a robust, efficient wind turbine. Thinair 102 is a one blade downwind stall-regulated turbine designed to maximise power in gusty winds. However, rapid variations in Tip Speed Ratio (TSR) due to wind speed can be detrimental to the turbine and controller from the changing blade stall fraction over very short time periods. In order to optimise future blade design and improve the response of the control system to such fluctuations in power output understanding stall on the blade is crucial. This research therefore predicts stall behaviour of the blade for a range of TSR using observational and simulation methods.

A turbine blade was instrumented with tufts attached to the blade and a camera mounted on the hub. Digital post processing output was a stall intensity map and the blade stall fraction. Additionally Computational Fluid Dynamics (CFD) and Blade Element Method simulations were computed for a range of TSR.

Three distinct regions of stall on the Thinair 102 blade at lower TSR were found from the observations and three-dimensional simulation results. The stall in the central part of the blade was found to have the most significant effect on the torque and thrust from the turbine. Predictions for power output at higher wind speeds changes with numerical method used. The stall fraction on the blade was observed to be periodic with decreasing amplitude over time due to the tower shadow effect as the blade path sweeps around.