A Numerical Study of Eccentricity Effect to Heat Transfer Under Single Phase Force Convection Inside a Vertical Annulus

2013 ◽  
Author(s):  
Yang Liu ◽  
Qianqian Jia ◽  
Haijun Jia
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Stokes Equations ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Force Convection ◽  
Convection Heat ◽  
Eccentric Annulus ◽  
Eccentricity Effect ◽  
Vertical Annulus

Because annulus channel can be used to develop high efficiency compact heat exchangers, the heat transfer in annulus channel has become great interest to researchers in recent years. Most of the studies focus on the vertical concentric and horizontal eccentric annulus. The investigations about single phase force convection heat transfer inside a vertical eccentric annulus are not enough. In this work, force convection heat transfer is numerically studied to determine the eccentricity effect inside a vertical annulus. For this purpose, full Reynolds-averaged Navier-Stokes equations along with energy equations are solved in a 3-D grid. The discrete method of the equations is based on finite-volume method and the turbulence model is RNG k-ε model. The radius ratio of the annulus is 0.8 in this work. Heat flux of one wall is constant while the other is insulated. Firstly, the feasibility and exactness of the numerical method is proved by comparing the Nusselt number with experiment in concentric annulus. Then the effect of eccentricity is studied in detail.

A numerical study of the hydro-thermal behaviour of nanofluids in rectangular microchannels using a mixture model

2011 ◽  
Vol 225 (4) ◽  
pp. 791-798 ◽  
Author(s):  
H Aminfar ◽  
R Maroofiazar
Keyword(s):  
Heat Transfer ◽  
Mixture Model ◽  
Single Phase ◽  
Numerical Study ◽  
Pure Water ◽  
Convection Heat Transfer ◽  
Phase Model ◽  
Convection Heat ◽  
Rectangular Microchannel ◽  
The Difference

In this article, laminar flow and convection heat transfer of wateralumina nanofluid in a rectangular microchannel have been investigated numerically. Because of the existence of slip velocity between nanoparticles and base fluid, the mixture model is used and results are compared with the single-phase model. The results indicate that using nanofluids can enhance convective heat transfer and pressure drop in a microchannel in comparison with pure water. Also, the enhancement of convection heat transfer is higher in the developing region and the difference of the mixture model and single-phase model is slightly great in this region, but in fully developed region the differences are very low.

scholarly journals Thermal behavior of premises equipped with different alveolar structures

2015 ◽  
Vol 19 (3) ◽  
pp. 929-938
Author(s):  
Nour Lajimi ◽  
Noureddine Boukadida
Keyword(s):  
Heat Transfer ◽  
Thermal Behavior ◽  
Air Temperature ◽  
Numerical Study ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Point Temperature ◽  
Set Point ◽  
Alveolar Structure ◽  
Vertical Walls

This paper presents a numerical study of local thermal behavior. Vertical walls are equipped with alveolar structure and/or simple glazing in East, South and West frontages. Local temperature is assumed to be variable with time or imposed at set point temperature. Results principally show that the simple glazing number has a sensitive effect on convection heat transfer and interior air temperature. They also show that the diode effect is more sensitive in winter. The effect of alveolar structure and simple glazing on the power heating in case with set point temperature is also brought out.

Sign in / Sign up

Export Citation Format

Share Document