Mike Cheadle PhD Graduate Student Mechanical Engineering

1. Mike Cheadle PhD Graduate StudentMechanical Engineering Thesis: Determination of Oscillating Flow Heat Transfer and Hydrodynamic Parameters for a Cryogenic Regenerator

2. Determination of Oscillating Flow Heat Transfer and Hydrodynamic Parameters for a Cryogenic Regenerator • Regenerator models used by designers are macro-scale models that do not explicitly consider the interaction between the fluid and solid matrix. • Correlations of Nusselt number and pressure drop used to calculate heat transfer and pressure drop, respectively, are based on steady flow data rather than oscillating flow data. The error from using these correlations is unknown. • Experimental data for oscillating flow friction factor and Nusselt number exist in the literature, but results are conflicting. Some studies suggest oscillations have no effect and others suggest that the friction factor and Nusselt number increase substantially to their steady flow values. • CFD modeling of oscillating flow is limited to macro-scale porous media models. • Micro-scale CFD modeling and experimental measurements are being performed to determine the effects of oscillating flow on the heat transfer and hydrodynamic parameters of a cryogenic regenerator.

3. Uniform heat flux, Uniform outlet pressure, Uniform inlet velocity, CFD Modeling Strategy Regenerator unit cell Micro-scale CFD model of a unit cell (or multiple unit cells) of the regenerator matrix in order to derive oscillating flow correlations for Nusselt number and friction factor. Multiple Unit Cells Symmetry boundary He 1 2 n

4. Experimental Schematic reservoir compressor regenerator matrix P P P P T T T T Pressure measurement P aftercooler heater Temperature measurement T Schematic of the experimental apparatus that will be used to determine oscillating flow correlations for Nusselt number and friction factor.