James Menart (Advisor), Mitch Wolff (Committee Member), Zifeng Yang (Committee Member)
Master of Science in Mechanical Engineering (MSME)
At the present time, the magnitude of transient convective heat transfer is approximated using heat transfer coefficient correlations developed for steady state conditions. This is done by necessity, as transient heat transfer correlations are not readily available. There is a rare transient heat transfer correlation found in the literature, but the number of correlations available can be counted on one hand. In addition, the literature does provide some plots of Nusselt numbers for specific cases of transient convective heat transfer, but these are limited to the specific case for which they were developed. The work presented in this thesis is a first step in an attempt to produce heat transfer coefficient correlations, in the form of Nusselt numbers, for transient single phase convective heat transfer. The primary objective of the present work was to develop a computer program that simulates transient convective heat transfer for laminar fluid flow between parallel plates. This objective was met; and this computer program is described in this thesis. The fundamental laws upon which this computer program are based are conservation of mass, conservation of momentum, and conservation of energy. Essentially an unsteady, two-dimensional, Cartesian coordinate version of the Navier-Stokes equations is used. These equations are used because of their physical fidelity in simulating convective heat transfer; in particular, their ability to simulate transient convective heat transfer. The developed computer program simulates both transient velocity fields and transient temperature fields. To prove the accuracy of the developed computer model, a detailed comparison of computed transient convective fluxes is made to published transient convective fluxes. This is done for the case where a fully developed, steady velocity field is used and only the temperature fields are undergoing transients. Detailed results as a function of time and position along the walls of the parallel plate flow channel have been published in the Handbook of Convective Heat Transfer. The comparisons produced by the developed computer program to the published results are close, but differ slightly in certain regions. It is the claim of the author that this proves the accuracy of the computer model developed here. The differences that result are probably due to small inaccuracies in the series solution used to obtain the published results. In addition to comparison results, convective heat transfer results are presented for the case where both the velocity and temperature fields are undergoing transients. It is found that for the case studied, the velocity field transients end much quicker than the temperature field transients. There are differences caused by adding the velocity field transients to the temperature field transients as compared to the transients caused by just varying temperature fields; however, the differences are small. Also included in this thesis are detailed results showing how the temperature, velocity, and pressure fields change with time.
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
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