Understanding and Controlling Hydrodynamic Cavitation to Improve Manufacturing Processes Involving High Velocity Fluid Flow

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This grant supports research that contributes new knowledge in the manufacturing field, promoting both progress of science and engineering and advancing national prosperity. Hydrodynamic cavitation is the formation, growth, and burst of gas bubbles in a rapidly flowing fluid. The resulting implosion of gas bubbles releases concentrated energy as pressure waves or high-speed micro jets. The impact of this project is on multiple fronts; the potential to reduce total energy spent in manufacturing processes, increase in the quality of the produced parts and fabrication of part features that are difficult to achieve with conventional manufacturing processes. The knowledge gained from this project could also be used to enhance the efficiency of existing cavitation-based systems in other areas beyond manufacturing such as cleaning devices, water purification, and homogenization of industrial and food products. The experimental and analytical work emanating from this project provides excellent educational opportunities to graduates and undergraduate students participating in the research. Particular emphasis is placed on engaging women and minority students in this project. The project also supports several classroom teaching initiatives within the manufacturing curriculum.The goal of this project is to advance the fundamental understanding of mechanisms for producing hydrodynamic cavitation from a high velocity fluid stream in a manufacturing process so that the pressure waves and micro-jets produced by this cavitation could be utilized to enhance the process. A combination of experimentation and analytical and numerical modeling is used to study different mechanisms for producing and controlling hydrodynamic cavitation. The study includes (1) characterization of hydrodynamic cavitation intensity via novel flow-induced vibration at various resonance frequencies, (2) characterization of vortex flows that can generate continuous and fully cavitating fluid streams thus increasing the yield on the energy to be harvested, and (3) development of mechanisms for creating self-resonating flows via superposition of pressure waves aimed at enhancing bubble collapse frequency. The analytical modeling provides an estimate of pressure induced during bubble collapse, whereas numerical modeling provides field variables depicting distribution behavior of cavitation in the fluid domain. To quantify the cavitation power density obtained from the above mechanisms, residual stresses and microhardness distributions measured from samples are mapped with field variables from numerical and analytical models. This project is aimed at creating a knowledge base to facilitate utilization of the cavitation energy to enhance manufacturing processes that involve high velocity fluid flow such as water jet cutting, water jet peening for surface treatment, nano-lubricant formulation, and polishing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.