Mechanical Engineering MS Thesis Defense by Mr. Koray Senol
When: Monday,
June 20, 2016
1:00 PM
-
3:00 PM
Where: Textiles Building 101E
Description: The Mechanical Engineering Department is pleased to announce the MS THESIS DEFENSE of Mr. Koray Senol
June 20, 2016
1:00 p.m. 3:00 p.m.
Textile Building, Room 101E
TOPIC:
A Computational Study on the Power Takeoff Techniques for Bottom-Hinged, Flap-Type Wave Energy Converters
ABSTRACT:
In this thesis, the machine dynamics of a bottom hinged flap-type wave energy converter WEC was studied through computational simulations in order to better understand and improve the power takeoff (PTO) techniques, and ultimately enhance the energy extraction. The computational model was developed in Comsol Multiphysics 5.1 using its Multibody Dynamics Module. Both the linear and non-linear dynamics of the flap in response to regular waves were considered. The hydrodynamic coefficients were obtained from the linear wave theory. The computational model was carefully validated and then employed to perform several parametric studies. A limit on the amplitude of flap oscillations was assumed to (a) ensure that the linear wave theory remains valid, and (b) address performance challenges such as structural strength of the device, and large variability in the oscillations. A brake mechanism was devised to impose the prescribed limit on the amplitude of oscillations. With that limit imposed, it was observed from the simulations that there exists a range of wave frequency where the optimum damping coefficient, i.e., PTO, proposed in the literature does not actually lead to the optimum energy extraction. Over that frequency range, the brake mechanism becomes engaged, which results in significant energy loss. The idea pursued in this thesis was to recover the energy lost to the brake mechanism by proposing new PTO techniques that would avoid the engagement of the brake, yet ensure that the amplitude of oscillations remain in the specified range. New PTO techniques are proposed for both the linear and non-linear flap dynamics through parametric studies. The efficacy of the proposed PTO techniques are demonstrated for several flap geometries where the linear and non-linear WEC dynamics are modeled. This study concludes that the energy loss due to the engagement of the brake can be minimized or eliminated through the proposed PTO techniques, thereby enhancing the energy extraction of the wave energy converters.
ADVISOR:
Dr. Mehdi Raessi, Department of Mechanical Engineering
COMMITTEE MEMBERS:
Dr. Sankha Bhowmick, Department of Mechanical Engineering
Dr. Mazdak Tootkaboni, Department of Civil and Environmental Engineering
Open to the public. All MNE students are encouraged to attend.
For more information please contact:
Dr. Mehdi Raessi (mraessi@umassd.edu, 508-999-8496)
June 20, 2016
1:00 p.m. 3:00 p.m.
Textile Building, Room 101E
TOPIC:
A Computational Study on the Power Takeoff Techniques for Bottom-Hinged, Flap-Type Wave Energy Converters
ABSTRACT:
In this thesis, the machine dynamics of a bottom hinged flap-type wave energy converter WEC was studied through computational simulations in order to better understand and improve the power takeoff (PTO) techniques, and ultimately enhance the energy extraction. The computational model was developed in Comsol Multiphysics 5.1 using its Multibody Dynamics Module. Both the linear and non-linear dynamics of the flap in response to regular waves were considered. The hydrodynamic coefficients were obtained from the linear wave theory. The computational model was carefully validated and then employed to perform several parametric studies. A limit on the amplitude of flap oscillations was assumed to (a) ensure that the linear wave theory remains valid, and (b) address performance challenges such as structural strength of the device, and large variability in the oscillations. A brake mechanism was devised to impose the prescribed limit on the amplitude of oscillations. With that limit imposed, it was observed from the simulations that there exists a range of wave frequency where the optimum damping coefficient, i.e., PTO, proposed in the literature does not actually lead to the optimum energy extraction. Over that frequency range, the brake mechanism becomes engaged, which results in significant energy loss. The idea pursued in this thesis was to recover the energy lost to the brake mechanism by proposing new PTO techniques that would avoid the engagement of the brake, yet ensure that the amplitude of oscillations remain in the specified range. New PTO techniques are proposed for both the linear and non-linear flap dynamics through parametric studies. The efficacy of the proposed PTO techniques are demonstrated for several flap geometries where the linear and non-linear WEC dynamics are modeled. This study concludes that the energy loss due to the engagement of the brake can be minimized or eliminated through the proposed PTO techniques, thereby enhancing the energy extraction of the wave energy converters.
ADVISOR:
Dr. Mehdi Raessi, Department of Mechanical Engineering
COMMITTEE MEMBERS:
Dr. Sankha Bhowmick, Department of Mechanical Engineering
Dr. Mazdak Tootkaboni, Department of Civil and Environmental Engineering
Open to the public. All MNE students are encouraged to attend.
For more information please contact:
Dr. Mehdi Raessi (mraessi@umassd.edu, 508-999-8496)
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