Simulation of refrigerated space with radiation

Bayer, Özgür
Performance of a refrigerator can be characterized with its ability to maintain a preset low temperature by spending the least amount of electricity. It is important to understand natural convection inside a refrigerator for optimizing its design for performance. Computational Fluid Dynamics (CFD) together with experiments is a very powerful tool for visualizing flow and temperature fields that are essential for understanding a phenomenon that involves both fluid and heat flow. In this aspect, simulations are performed for compartment and total refrigerator models using the package program Fluent which is based on finite volume method. An experimental study is performed to determine the constant wall temperature boundary conditions for the numerical models. Effect of radiation is also investigated by comparing the numerical study of a different full refrigerator model with a similar one in literature. While evaluating the radiation effect, convection boundary condition is selected by defining overall heat transfer coefficient between the ambient room air at a constant temperature and the inner surfaces of the walls. Based on assumptions, related heat transfer analyses are done using compartment and total refrigerator model analyses. Performing CFD simulations of a refrigerator cabinet for visualizing the flow and temperature fields which is the aim of the study is achieved and some observations that can be useful in design optimization are made.


Performance anallysis of an intermediate temperature solid oxide fuel cell
Timurkutluk, Bora; Tarı, İlker; Department of Mechanical Engineering (2007)
An intermediate temperature solid oxide fuel cell (SOFC) is developed and its performance is investigated experimentally and theoretically. In the experimental program, a gadolinium doped ceria based membrane electrode group is developed with the tape casting and screen printing methodology and characterized. An experimental setup is devised for the performance measurement of SOFCs and the performance of produced cells is investigated over a range of parameters including the electrolyte thickness, the sinte...
Numerical investigation on cooling of small form factor computer cases
Orhan, Ömer Emre; Tarı, İlker; Department of Mechanical Engineering (2007)
In this study, cooling of small form factor computer is numerically investigated. The numerical model is analyzed using a commercial computational fluid dynamics software Icepak™ . The effects of grid selection, discretization schemes and turbulence models are discussed and presented. In addition, physical phenomena like recirculation and relaminarization are addressed briefly. For a comparison with the computational fluid dynamics results, an experiment is conducted and some temperature measurements are ob...
Numerical and experimental investigation of forced filmwise condensation over bundle of tubes in the presence of noncondensable gases
Ramadan, Abdul-Ghani M; Yamalı, Cemil; Department of Mechanical Engineering (2006)
The problem of the forced film condensation heat transfer of pure steam and steam-air mixture flowing downward a tier of horizontal cylinders is investigated numerically and experimentally. Liquid and vapor-air mixture boundary layers were solved by an implicit finite difference scheme. The effects of the free stream non-condensable gas (air) concentration, free stream velocity (Reynolds number), cylinder diameter, temperature difference and angle of inclination on the condensation heat transfer are analyze...
A comparative investigation of heat transfer capacity limits of heat pipes
Küçük, Sinan; Tarı, İlker; Department of Mechanical Engineering (2007)
Heat pipe is a passive two phase device capable of transferring large rates of heat with a minimal temperature drop. It is a sealed tube with a wick structure lined in it and with a working fluid inside the tube. It consists of three parts: an evaporator, a condenser and an adiabatic section. The heat pipes are widely used in electronics cooling and spacecraft applications. Although they can transfer large rate of heat in a short range, they have operating limits, namely: the capillary limit, the viscous li...
Atay, Atakan; Sariarslan, Busra; Kuscu, Yigit F.; Saygan, Samet; Akkus, Yigit; Gurer, A. Turker; Cetin, Barbaros; Dursunkaya, Zafer (2019-01-01)
Heat pipes are widely used in thermal management of high heat flux devices due to their ability of removing high heat loads with small temperature differences. While the thermal conductivity of standard metal coolers is approximately 100-500 W/m.K, effective thermal conductivities of heat pipes, which utilize phase-change heat transfer, can reach up to 50,000 W/m.K. In industrial applications, commercially available heat pipes are commonly preferred by thermal engineers due to their low cost and versatility...
Citation Formats
Ö. Bayer, “Simulation of refrigerated space with radiation,” Ph.D. - Doctoral Program, Middle East Technical University, 2009.