Natural Convection Heat Transfer within Octagonal Enclosure
نویسندگان
چکیده مقاله:
The problem of steady, laminar and incompressible natural convection flow in an octagonalenclosure was studied. In this investigation, two horizontal walls were maintained at a constant hightemperature, two vertical walls were kept at a constant low temperature and all inclined walls wereconsidered adiabatic. The enclosure was assumed to be filled with a Bousinessq fluid. The studyincludes computations for different Prandtl numbers Pr such as 0.71, 7, 20 and 50 whereas the Rayleighnumber Ra was varied from 103 to 106. The pressure-velocity form of Navier-Stokes equations andenergy equation were used to represent the mass, momentum and energy conservations of the fluidmedium in the enclosure. The governing equations and boundary conditions were converted todimentionless form and solved numerically by penalty finite element method with discretization bytriangular mesh elements. Flow and heat transfer characteristics were presented in terms of streamlines,isotherms and average Nusselt number Nu. Results showed that the effect of Ra on the convection heattransfer phenomenon inside the enclosure was significant for all values of Pr studied (0.71-50). It wasalso found that, Pr influence natural convection inside the enclosure at high Ra (Ra > 104).
منابع مشابه
Two-dimensional simulations of natural convection/radiation heat transfer for BWR assembly within isothermal enclosure
The current scoping study identifies the significant heat transfer effects for a 767 boiling water reactor (BWR) assembly within an isothermal basket opening inside a transport cask. A twodimensional finite volume mesh is constructed that models the assembly components and cover gas. Computational fluid dynamics (CFD) simulations calculate the buoyancy induced gas motion, conduction and radiati...
متن کاملEnhancement of Natural Convection Heat Transfer in Annular Enclosures
Natural convection heat transfer was investigated experimentally in a concentric-cylinders annulus. To enhance the rate of heat transfer, pin fins were installed on the surface of the inner cylinder. Two fin arrangements were employed, namely, staggered and in-line arrangements. The length of the fins varied from 2 to 8 cm and the Rayleigh number Ra changed in the range from 5 x 105 to 5 x 106...
متن کاملCFD simulations on natural convection heat transfer of alumina-water nanofluid with Brownian motion effect in a 3-D enclosure
The CFD simulation has been undertaken concerning natural convection heat transfer of a nanofluid in vertical square enclosure, whose dimension, width height length (mm), is 40 40 90, respectively. The nanofluid used in the present study is -water with various volumetric fractions of the alumina nanoparticles ranging from 0-3%. The Rayleigh number is . Fluent v6.3 is used to simulate nanofluid ...
متن کاملHeterogeneous nanofluids: natural convection heat transfer enhancement
Convective heat transfer using different nanofluid types is investigated. The domain is differentially heated and nanofluids are treated as heterogeneous mixtures with weak solutal diffusivity and possible Soret separation. Owing to the pronounced Soret effect of these materials in combination with a considerable solutal expansion, the resulting solutal buoyancy forces could be significant and ...
متن کاملNumerical simulation of mixed convection heat transfer of nanofluid in an inclined enclosure by applying LBM
Mixed convection of Cu-Water nanofluid is studied numerically in a shallow inclined enclosure by applying lattice Boltzmann method. The D2Q9 lattice and internal energy distribution function based on the BGK collision operator are used in order to develop the thermal flow field. The enclosure's hot lid has the constant velocity of U0 while its cold lower wall has no motion. Moreover, sidewalls ...
متن کاملمنابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ذخیره در منابع من قبلا به منابع من ذحیره شده{@ msg_add @}
عنوان ژورنال
دوره 23 شماره 1
صفحات 1- 10
تاریخ انتشار 2010-01-01
با دنبال کردن یک ژورنال هنگامی که شماره جدید این ژورنال منتشر می شود به شما از طریق ایمیل اطلاع داده می شود.
میزبانی شده توسط پلتفرم ابری doprax.com
copyright © 2015-2023