Free convection heat transfer in a stratified medium – cavity problem

Download
2013
Kayserilioğlu, Yavuz Selim
A numerical study is performed in order to simulate a 2D cavity filled with water having one inlet and one outlet. Relatively warm water is fed to the cavity to charge it while relatively cooler water is drained from the outlet. The top surface of the cavity is exposed to ambient air. Bottom surface is insulated while vertical side surfaces are cooled. Mathematical model comprised of laminar 2D transient flow of an incompressible fluid. Momentum and energy equations are solved simultaneously with Boussinesq approximation since both forced and natural convection occur within cavity. The charging period of the cavity with relatively hot charging water is examined. Velocity and temperature fields for cavity are presented. Effects of initial temperature, ambient air temperature, inlet charging temperature, and solar radiation on free surface are examined. It is found that lower initial storage temperature, higher ambient air temperature, higher charging water temperature, and existence of solar radiation have positive effects on the performance of cavity. Heat removal period from cavity is examined. Basic heat removal tubes with rectangular cross-sections are modeled as negative heat generation sources. Heat removal process affects regions below the tubes more than regions above the tubes. The effect of heat removal is seen all the way down to bottom of the cavity whereas only a couple of centimeters above the heat removal tubes are affected. As a result, when heat is removed from a lower layer, stored energy content of cavity at the end of heat removal is higher.

Suggestions

Theoretical investigation of conjugate condensation heat transfer inside vertical tubes
Köse, Serhat; Yeşin, Ahmet Orhan; Department of Mechanical Engineering (2010)
Based on the well-known theoretical studies related to the film condensation inside vertical tubes, a known temperature distribution is prescribed as boundary condition at the inner surface of the tube wall. But, in reality, there is a thermal interaction between the condensate fluid and conduction through the wall where the temperature variation along the inner surface of the tube wall is unknown and this unknown temperature profile should be determined by taking account of this interaction. In other words...
Experimental and three dimensional numerical analysis of cylindrical solar cooling adsorbent beds with circular heat exchange coils
Gözükara, Arif Cem; Yamalı, Cemil; Department of Mechanical Engineering (2016)
In this study three dimensional cylindrical adsorbent bed designs with circular heat transfer fluid paths had been investigated numerically and experimentally. Three dimensional high fidelity numerical coupled heat and mass transfer analyses of the proposed design alternatives are performed. Numerical analysis results are compared with the results of experiments using the temperature distributions within the adsorbent bed. In addition to geometric design features, effects of initial adsorption capacity, hea...
Modeling of fluid -vapor interface in the condensation zone of a grooved heat pipe
Alipour, Mobin; Dursunkaya, Zafer; Department of Mechanical Engineering (2017)
Condensation in grooved heat pipes involves several simultaneous phenomena including vapor-liquid boundaries whose shapes are unknown a priori, fluid flow due to capillary and dispersion pressure gradients and condensation over ultra thin films. In grooved heat pipes, the majority of condensation occurs on fin tops due to the thinner liquid film, having a lower thermal resistance, compared to inside the groove where the fluid is substantially thicker. Majority of the studies in the literature assume an appr...
Performance of rectangular fins on a vertical base in free convection heat transfer
Yazıcıoğlu, Burak; Yüncü, Hafit; Department of Mechanical Engineering (2005)
The steady-state natural convection heat transfer from vertical rectangular fins extending perpendicularly from vertical rectangular base was investigated experimentally. The effects of geometric parameters and base-to-ambient temperature difference on the heat transfer performance of fin arrays were observed and the optimum fin separation values were determined. Two similar experimental set-ups were employed during experiments in order to take measurements from 30 different fin configurations having fin le...
Numerical simulation of thermal convection under the influence of a magnetic field by using solenoidal bases
Yarımpabuç, Durmuş; Tarman, Işık Hakan; Department of Engineering Sciences (2011)
The effect of an imposed magnetic field on the thermal convection between rigid plates heated from below under the influence of gravity is numerically simulated in a computational domain with periodic horizontal extent. The numerical technique is based on solenoidal basis functions satisfying the boundary conditions for both velocity and induced magnetic field. The expansion bases for the thermal field are also constructed to satisfy the boundary conditions. The governing partial differential equations are ...
Citation Formats
Y. S. Kayserilioğlu, “Free convection heat transfer in a stratified medium – cavity problem,” Ph.D. - Doctoral Program, Middle East Technical University, 2013.