Fluid oscillations and enhanced heat transfer in a parallel-plate channel bounded by end reservoirs maintained at different temperature

Existing analytic and experimental studies have shown that sinusoidal oscillations of a viscous fluid within open ended conduits connected to reservoirs can enhance the thermal diffusivity between the hot fluid and cold fluid in the opposite end reservoirs by some four orders of magnitude in excess of that possible in the absence of oscillation. The heat transfer coefficients achieved in this process can be very high and can readily exceed those possible via heat pipes, yet involve no net convective mass exchange.;A numerical investigation of laminar oscillating flows of incompressible viscous fluid and the associated enhanced heat transfer in a 2D parallel plate channel bounded by rectangular end reservoirs which have sinusoidally oscillating piston boundaries and are maintained at different temperatures forms the topic of the present dissertation.;A modification of the widely used SIMPLE algorithm, termed SIMPLE-TP (for Time Periodic), has been developed to take time periodicity and boundary movements into account. The method has been successfully applied to the present time periodic flow and heat transfer problem.;Two different models of heat supply and removal, namely, conduction through the reservoir walls and convection by cross flow, were considered in this study. Several case studies involving different combinations of Womersley number, tidal displacement, length of reservoirs and cross flow velocities were carried out. The numerical results obtained were compared with analytic solutions where such comparisons were possible.;It was found that the velocity field in each reservoir is characterized by a high velocity jet emanating from the channel end during a portion of the oscillation cycle and that one or more counterrotating vortex(es) or vortex pair(s) exist during the whole oscillation cycle as long as the Reynolds number, based on the maximum piston velocity and reservoir width, is large enough. The tidal displacement and cross flow velocity have a strong effect on the flow patterns in reservoir and the reservoir temperature field is mainly determined by the temperature boundary conditions and less so by the velocity field. High oscillation frequencies coupled with a large tidal displacement and a relatively large cross flow velocity are found to yield large enhancements of heat transfer. Heat transfer coefficient as high as 1.8...