An experimental study of transient torque and power number for heat generator design in wind thermal energy conversion

Nazari, Navid (2023) An experimental study of transient torque and power number for heat generator design in wind thermal energy conversion. Masters thesis, Memorial University of Newfoundland.

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This research focuses on assessing the heat generator design for wind thermal energy conversion technology, in which wind power is directly converted into heat. Although several technologies have been proposed and investigated for heat generation, water heating through liquid agitation is selected for wind-to-heat conversion due to its simplicity and high potential for commercialization. In this research, the technical challenges of the technology were understood by analyzing the system's performance during different operating conditions. It was seen that the system's performance under transient operating condition is of question since there is no literature available regarding the characteristics of the agitator’s torque in baffled tanks during unsteady operation. Therefore, an experimental setup was designed and constructed for parametric study. The flow field inside the agitator was investigated by calculating the power number (Nₚ) of two impellers. This study considered several transient operation modes: acceleration, deceleration, and variable shaft velocity (sinusoidal). The analysis suggests that Nₚ in transient condition differs from the steady-state operation, which is an important outcome when matching an agitator to a wind turbine. The results show that the transient Nₚ is directly correlated to the angular acceleration/deceleration rate with higher sensitivity to the acceleration rather than deceleration. Furthermore, when the angular velocity of the impeller follows a sinusoidal profile, the change in transient Nₚ is affected by both frequency and amplitude. Finally, the temperature rise of the working fluid (distilled water) is measured during a 60-minute test by applying two different velocity profiles: constant angular velocity and sinusoidal velocity profiles. The results reveal that the sinusoidal velocity profile requires more input power, leading to a higher temperature rise than the constant angular speed operation.

Item Type: Thesis (Masters)
Item ID: 16360
Additional Information: Includes bibliographical references (pages 104-116)
Keywords: wind-thermal energy conversion, experimental study, transient operation, torque, power number, fluid agitator
Department(s): Engineering and Applied Science, Faculty of
Date: September 2023
Date Type: Submission
Digital Object Identifier (DOI):
Library of Congress Subject Heading: Wind power; Heat--Transmission; Thermodynamics; Energy conversion; Torque

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