HEAT CONVECTION IN A VERTICAL AND IN A TILTED CHANNEL

2009 ◽  
Author(s):  
Jean-Christophe Tisserand ◽  
Mathieu Creyssels ◽  
Mathieu Gibert ◽  
Bernard Castaing ◽  
Francesca Chilla
Keyword(s):  
Heat Convection

Spatial temperature distribution in CW CO2 laser photosensitized reactions

1984 ◽  
Vol 49 (6) ◽  
pp. 1354-1359 ◽  
Author(s):  
Pavel Kubát ◽  
Josef Pola
Keyword(s):  
Temperature Distribution ◽  
Chemical Reactions ◽  
Co2 Laser ◽  
Computational Procedure ◽  
Heat Convection ◽  
Inert Gas ◽  
Spatial Temperature Distribution ◽  
Cw Co2 Laser ◽  
Spatial Temperature

The temperature distribution in gaseous SF6 and SF6-inert gas samples under irradiation with cw CO2 laser measured by a thermocouple technique is confronted with the results of a computational procedure neglecting heat convection. The results are helpful in understanding the effect of the inert gas on the distribution of temperature and the size of the reacting hot volume in the cw laser-photosensitized chemical reactions.

scholarly journals Analysis of transient mixed convection in a horizontal channel partially heated from below

2021 ◽  
Vol 4 (8(112)) ◽  
pp. 16-22
Author(s):  
Mahmoud A. Mashkour
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Source ◽  
Local Nusselt Number ◽  
Richardson Number ◽  
Stokes Equations ◽  
Heat Convection ◽  
Horizontal Channel ◽  
Outlet Temperature

The heat convection phenomenon has been investigated numerically (mathematically) for a channel located horizontally and partially heated at a uniform heat flux with forced and free heat convection. The investigated horizontal channel with a fluid inlet and the enclosure was exposed to the heat source from the bottom while the channel upper side was kept with a constant temperature equal to fluid outlet temperature. Transient, laminar, incompressible and mixed convective flow is assumed within the channel. Therefore, the flow field is estimated using Navier Stokes equations, which involves the Boussinesq approximation. While the temperature field is calculated using the standard energy model, where, Re, Pr, Ri are Reynolds number, Prandtl number, and Richardson number, respectively. Reynolds number (Re) was changed during the test from 1 to 50 (1, 10, 25, and 50) for each case study, Richardson (Ri) number was changed during the test from 1 to 25 (1, 5, 10, 15, 20, and, 25). The average Nusselt number (Nuav) increases exponentially with the Reynold number for each Richardson number and the local Nusselt number (NuI) rises in the heating point. Then gradually stabilized until reaching the endpoint of the channel while the local Nusselt number increases with a decrease in the Reynolds number over there. In addition, the streamlines and isotherms patterns in case of the very low value of the Reynolds number indicate very low convective heat transfer with all values of Richardson number. Furthermore, near the heat source, the fluid flow rate rise increases the convection heat transfer that clarified the Nusselt number behavior with Reynolds number indicating that maximum Nu No. are 6, 12, 27 and 31 for Re No. 1, 10, 25 and 50, respectively

scholarly journals OPTIMASI RONGGA TERHADAP VARIASI DERAJAT KEVAKUMAN SEBAGAI ISOLATOR

2012 ◽  
Vol 11 (1) ◽  
pp. 63 ◽  
Author(s):  
MULYONO MULYONO
Keyword(s):  
Heat Transfer ◽  
Specific Gravity ◽  
Thermal Resistance ◽  
Heat Convection ◽  
Vacuum Pressure ◽  
Temperature Conductivity ◽  
Easy Task ◽  
Insulation Materials ◽  
The World ◽  
Natural Heat Convection

In the world of industry, insulation materials are often utilized to maintain the temperature,either low or high. However, since the insulation materials often need to be thick, thus,costly, they are frequently deemed impractical. Therefore, in the attempt to replace the insulationmaterials, a cavity with low vacuum pressure is opted for. Yet, to attain a total (100%) airfreecavity is not an easy task. Such, the cavity usually still bears some amount of air pressurewhich results in natural heat convection through the two surfaces making up the cavity. Thetransfer coefficient of natural heat convection (h) is influenced by some factors, such as, the temperaturedifference, geometry of the cavity, cavity orientation, and characteristics of the fluid,for instance, its pressure, temperature, conductivity, specific gravity (density), and viscosity.The purpose of the study is to find answers to the following question: “How do vacuum pressurevariation and cavity ratio affect the rate of natural heat convection through the a cavity?” Pertinentto the question, the study was aimed to find the appropriate value of the vacuum pressurewhich can function well as an insulator. This study is significant in the attempt to lower downthe rate of heat transfer taking place in a system vis-à-vis the surrounding media. The studyfound out that the degree of emptiness of -60 cm Hg and =5.96, results in a lower rate of heattransfer compared with -20 cm Hg and -40 cm Hg. This means that the vacuum pressure of-60cm Hg bears a bigger thermal resistance than the -20 cm Hg and -40 cm Hg do.

Sign in / Sign up

Export Citation Format

Share Document