Author: Stephen Alan SmithPublisher:
ISBN:
Category : Heat
Languages : en
Pages : 154
Book Description
Relative Size Limitations for Natural Convection Heat Transfer Within an Enclosure
Author: Stephen Alan SmithPublisher:
ISBN:
Category : Heat
Languages : en
Pages : 154
Book Description
Natural Convection in Enclosures--1983
Author: Ivan CattonNatural Convection Heat Transfer Within Enclosures at Reduced Pressures
Author: Peter Kevin BrownPublisher:
ISBN:
Category : Heat
Languages : en
Pages : 210
Book Description
Natural Convection and Radiation in Small Enclosures with a Non-attached Obstruction
Author: Jimmy Lynn LloydPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Numerical simulations were used to investigate natural convection and radiation interactions in small enclosures of both two and three-dimensional geometries. The objectives of the research were to (1) determine the relative importance of natural convection and radiation, and to (2) estimate the natural convection heat transfer coefficients. Models are generated using Gambit, while numerical computations were conducted using the CFD code FLUENT. Dimensions for the two-dimensional enclosure were a height of 2.54 cm (1 inch), and a width that varied between 5.08 cm and 10.16 cm (2 inches and 4 inches). The three-dimensional model had a depth of 5.08 cm (2 inches) with the same height and widths as the two-dimensional model. The obstruction is located at the centroid of the enclosure and is represented as a circle in the two-dimensional geometry and a cylinder in the three-dimensional geometry. Obstruction diameters varied between .51 cm and 1.52 cm (0.2 inches and 0.6 inches). Model parameters used in the investigation were average surface temperatures, net total heat flux, and net radiation heat flux. These parameters were used to define percent temperature differences, percent heat flux contributions, convective heat transfer coefficients, Nusselt numbers, and Rayleigh numbers. The Rayleigh numbers varied between 0.005 and 300, and the convective heat transfer coefficients ranged between 2 and 25 W/m2K depending on the point in the simulation. The simulations were conducted with temperatures ranging between 310 K and 1275 K on the right boundary. For right boundary temperatures above 800 K, the estimated error on the obstruction temperature is less than 6.1% for neglecting natural convection and conduction from the heat transfer analysis. Lower right boundary temperatures such as 310 K had significant contributions, over 50%, from heat transfer modes other than radiation. For lower right boundary temperatures, a means of including natural convection should be included. When a bulk fluid temperature and average surface temperature values are available, a time average heat transfer coefficient of 6.73 W/m2K is proposed for simplifying the numerical calculations. In the transient right boundary temperature analysis, all modes of heat transfer other than radiation can be neglected to have an error below 8.1%.
Natural Convection Heat Transfer from a Horizontal Disk in a Cylindrical Enclosure
Author: Duane Stewart Duncan (Jr)Publisher:
ISBN:
Category :
Languages : en
Pages : 57
Book Description
In the report the author discusses natural convection in water from a horizontal mirror finished disk, heated in the center and surrounded by a cylindrical enclosure. The test section was designed to insure a one dimensional heat flux. Measurements were taken with power inputs varying from 25 to 5 watts. Fluid depth had a definite effect on the heat transfer. An apparent maximum value existed at a ratio of enclosure radius to fluid depth of one. Comparison of the data with existing correlations however, was poor which led to the questioning of the validity of the assummed one dimensional heat flux. Use of a finite element computer program demonstrated that two dimensional effects were important. Subsequent modification of the heat transfer coefficient to account for this variation gave a correlation more in agreement with those existing in the literature. (Author).
Transient Natural Convection Heat Transfer Between Two Zones in an Insulated Enclosure
Author: Pedro Akos LitsekPublisher:
ISBN:
Category : Heat
Languages : en
Pages : 140
Book Description
Natural Convection in Enclosures
Author: Kenneth E. TorrancePublisher:
ISBN:
Category : Science
Languages : en
Pages : 136
Book Description
Natural Convection Heat Transfer in a Corrugated Enclosure
Author: Boniface Uwakwem ChimahPublisher:
ISBN:
Category :
Languages : en
Pages : 101
Book Description
Author: P. G. Simpkins
Author: Dong-Shiun Lin