TY - JOUR
T1 - Water turbines with a brimmed diffuser by using wind lens technology
AU - Watanabe, Koichi
AU - Ohya, Y.
N1 - Funding Information:
We gratefully acknowledge our laboratory staff, Mr. K. Watanabe, along with the student, Mr. Tanigawa for their cooperation and assistance in the experiments and in the analysis of the data. This research was supported by the New Energy and Industrial Technology Development Organization (NEDO).
Publisher Copyright:
© 2021 by Begell House, Inc.
PY - 2021
Y1 - 2021
N2 - A diffuser-type structure that is capable of collecting and accelerating the approaching wind and water flow has been developed. Namely, we have devised a diffuser shroud with a brim that is able to increase the approaching flow speed substantially by utilizing various flow characteristics, e.g., the generation of low-pressure region by vortex formation, flow entrainment by vortices, and so on, of the inner or peripheral flows of a diffuser shroud equipped with a brim. As a result, the shrouded wind turbines equipped with a brimmed diffuser (called wind-lens turbine, WLT) demonstrated power augmentation for a given turbine diameter and wind speed by a factor of about 2-5 compared to a standard wind turbine. The mechanism of the wind-lens technology can also be applied to the water flow. Water-lens turbine (WaLT) demonstrated 2.5-times power enhancement using a similar diffuser design used in a compact wind-lens turbine. In this research, we show some experimental and numerical results, focusing on a water turbine using wind-lens technology immersed into a water tank with a finite width and depth. Due to the effects of free surface and Venturi-shaped side walls, the maximum power coefficient Cw reaches 2.21 based on the rotor swept area, indicating 6-times increase compared to that for a conventional water turbine in an open flow.
AB - A diffuser-type structure that is capable of collecting and accelerating the approaching wind and water flow has been developed. Namely, we have devised a diffuser shroud with a brim that is able to increase the approaching flow speed substantially by utilizing various flow characteristics, e.g., the generation of low-pressure region by vortex formation, flow entrainment by vortices, and so on, of the inner or peripheral flows of a diffuser shroud equipped with a brim. As a result, the shrouded wind turbines equipped with a brimmed diffuser (called wind-lens turbine, WLT) demonstrated power augmentation for a given turbine diameter and wind speed by a factor of about 2-5 compared to a standard wind turbine. The mechanism of the wind-lens technology can also be applied to the water flow. Water-lens turbine (WaLT) demonstrated 2.5-times power enhancement using a similar diffuser design used in a compact wind-lens turbine. In this research, we show some experimental and numerical results, focusing on a water turbine using wind-lens technology immersed into a water tank with a finite width and depth. Due to the effects of free surface and Venturi-shaped side walls, the maximum power coefficient Cw reaches 2.21 based on the rotor swept area, indicating 6-times increase compared to that for a conventional water turbine in an open flow.
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U2 - 10.1615/INTERJENERCLEANENV.2020035110
DO - 10.1615/INTERJENERCLEANENV.2020035110
M3 - Article
AN - SCOPUS:85105432175
SN - 2150-3621
VL - 22
SP - 33
EP - 45
JO - International Journal of Energy for a Clean Environment
JF - International Journal of Energy for a Clean Environment
IS - 4
ER -