| Description | We are pleased to welcome Maha Haji, assistant professor at Cornell University's Sibley School of Mechanical and Aerospace Engineering, for an ME seminar. About the seminar:
Wave energy converters (WECs) can advance the global energy transition by producing clean power for utility grids and offshore technologies. WECs are inherently multidisciplinary. The energy generated is determined by the power take-off system (powertrain), controls, and hydrodynamic design, among other factors. The resultant forces must not exceed geometry-dependent structural limits, and all domains affect the system cost. Consequently, it is difficult to develop an optimal design that simultaneously considers the related objectives, constraints, and parameters. Multidisciplinary Design Optimization (MDO) has emerged as a powerful strategy to address such challenges. MDO is a quantitative design methodology that utilizes heuristic and gradient-based optimization algorithms to solve complex engineering design problems that involve multiple coupled disciplines. This talk discusses the ways in which MDO can be applied to both individual and arrays of WECs to improve their overall design. In the case of a single WEC, the Reference Model 3 (RM3), a two-body point absorber WEC, is simulated using a model employing linear hydrodynamics with force saturation and probabilistic waves. The RM3 geometry and controller parameters are optimized using sequential quadratic programming to minimize the levelized cost of energy (LCOE) and the coefficient of variation of power. In the case of arrays of WECs, four cylindrical, heaving point-absorber WECs are optimized to minimize the farm LCOE and maximum array dimension. The design variables are WEC radius, WEC position, and power take-off damping and the farm is optimized using a multi-objective genetic algorithm. Finally, the conceptual design of a wave-powered aquaculture farm, in which a WEC is co-located with a salmon farm for power production, is discussed. The farm is optimized to minimize cost-per-fish yield by adjusting the geometry of the WEC, the size of the net pens in the aquaculture farm, and the fish stocking density for a specific installation site. About the speaker:
Dr. Maha Haji is an Assistant Professor of Mechanical, Aerospace, and Systems Engineering at Cornell University. Her lab, the Symbiotic Engineering and Analysis (SEA) Lab develops designs for symbiotic offshore systems to sustainably extract resources from the ocean such as power, water, and food, as well as mineral resources key to the progress of clean energy. Her group’s current projects span wave energy converters, integrated pumped hydro and reverse osmosis systems, seawater lithium harvesters, and offshore hydrogen production. Previously, Prof. Haji was an MAE Faculty Fellow at Cornell and a Postdoctoral Associate in the Engineering Systems Laboratory in the Department of Aeronautics and Astronautics at MIT where her research focused on utilizing multidisciplinary design optimization to develop a floating platform, known as PEARL, to provide recharging and data offloading capacity for autonomous underwater vehicles. She received her Ph.D. in Mechanical and Oceanographic Engineering in 2017 from the Joint Program between MIT and Woods Hole Oceanographic Institution where she focused on the design and prototyping of a symbiotic system to harvest uranium from seawater. Prof. Haji has worked in industry as an engineering consultant at ATA Engineering, where she used analysis-driven design to solve problems ranging from aircraft and rockets to robotics and rollercoasters. She holds a B.S. in Mechanical Engineering and a B.A. in Applied Mathematics from the University of California, Berkeley. |
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