Date of Award
Mechanical, Automotive, and Materials Engineering
Computational Fluid Dynamics, Hybrid Model, Load Switched, Numerical Modelling, Super Plastic Forming, Supersonic Fluidic Oscillator
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Fluidic oscillators are devices capable of superimposing large pressure and velocity fluctuations on the flow through a device without the necessity of having any moving parts. The lack of moving parts makes these devices superior to conventional moving-part valves in high temperature applications. The specific application of interest in the current study is the super-plastic forming (SPF) process in which large sheets of aluminum at very high temperature are formed into the desired shape by pressurizing one side inside the SPF chamber. It is known that the introduction of pressure fluctuations onto the increasing pressure in the SPF chamber reduces the chances of the metal tearing. The use of a Bi-Stable Load-Switched Supersonic Fluidic Oscillator to create the large pressure fluctuation amplitudes is ideal for this application. A numerical investigation of a Bi-Stable Load-Switched Supersonic Fluidic Oscillator is performed to understand the performance of the device under a variety of operating conditions consistent with this application. The commercial CFD code ANSYS Fluent 17.0 is used in the present work. The computational time and memory required to complete a full three-dimensional (3D) model of the device are excessive and hence simplifications are made. This research includes a comparison of the results obtained from two such simplifications. These models are used to monitor the volume average pressure and temperature changes inside the feedback tanks and exhaust chambers during the filling process. This information is used to determine the frequency and amplitude of the pressure oscillation as well as the operational conditions at which the oscillations begin and end. The numerical simulations are also validated by comparing them with experimental results.
Sidhu, Lovepreet Singh, "Comparison of Hybrid Multi-dimensional Models of a Bi-Stable Load-Switched Supersonic Fluidic Oscillator Application" (2019). Electronic Theses and Dissertations. 7771.