The Joule Heating Effects on Natural Convection of Participating Magnetohydrodynamics Under Different Levels of Thermal Radiation in a Cavity

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Jing-Kui Zhang ◽  
Ben-Wen Li ◽  
Yuan-Yuan Chen

A numerical study is conducted for the Joule heating effects on fluid flow and heat transfer of radiatively participating magnetohydrodynamics (MHD) under different levels of thermal radiation considering the Hall effects in a square cavity. In the cavity, the vertical walls are isothermal with constant but different temperatures, while the horizontal walls are adiabatic. The absorption, emission, and scattering of the fluid and the reflection, absorption, and emission of the walls are all taken into account. The governing equations for momentum and energy together with the boundary conditions are solved by the finite volume method (FVM), while the governing equation for radiative transfer is solved by the discrete ordinates method (DOM). Tabular and graphical results are presented in terms of streamlines, isotherms, Nusselt number, and the average temperature of the fluid. After detailed analysis, we found that the Joule heating has notable effects on fluid flow and heat transfer in the cavity and Joule heating cannot be neglected in certain range of parameters.

2015 ◽  
Vol 9 (3) ◽  
pp. 242 ◽  
Author(s):  
Efstathios Kaloudis ◽  
Dimitris Siachos ◽  
Konstantinos Stefanos Nikas

2013 ◽  
Vol 561 ◽  
pp. 460-465
Author(s):  
Dong Hui Zhang ◽  
Jiao Gao

The objective of this paper is to study the characteristic of a circular tube with a built-in arc belt on fluid flow and heat transfer in uniform wall temperature flows. Numerical simulations for hydrodynamically laminar flow was direct ran at Re between 600 and 1800. Preliminary results on velocity and temperature statistics for uniform wall temperature show that, arc belt can swirl the pipe fluid, so that the fluid at the center of the tube and the fluid of the boundary layer of the wall can mix fully, and plays the role of enhanced heat transfer, but also significantly increases the resistance of the fluid and makes the resistance coefficient of the enhanced tube greater than smooth tube. The combination property PEC is all above 1.5.


Author(s):  
CJ Ho ◽  
GN Sou ◽  
CM Lai

This paper presents a numerical study of transient buoyancy-induced fluid flow and heat transfer between two horizontal, differentially heated pipelines inside a circular, air-filled enclosure. Numerical simulations based on the finite difference method were conducted to investigate the flow mode transition of the buoyant airflow and its effects on the heat transfer characteristics of the pipelines. The results indicate that the fluid flow complexity and the heat transfer of air between the pipelines are strongly affected by the Rayleigh number. When Ra = 6 × 105 and 1.2 × 106, both the flow field and the temperature distribution exhibit periodic variations with different patterns. The former ( Ra = 6 × 105) is a complete alteration of the flow direction from clockwise to counterclockwise, whereas the latter is a variation in the flow field strength that varies between strong and weak. The latter has a lower variation frequency than that of the former.


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