Role of working fluids on the cooling of discrete heated modules: a numerical approach

Abstract

The study has focused on the role of working fluids (air, water and FC-72) on the cooling of discrete heated modules under free, forced and mixed convection medium. Three non-identical protruding discrete heat sources are arranged at different positions on a substrate board following golden mean ratio (GMR). Numerical simulations for these heat sources are carried out using a commercial software (ANSYS-Icepak R-15) to simulate their flow and temperature fields under three different modes of heat transfer. Results suggest that the temperature of the heat sources is a strong function of their size, position on the substrate board, the velocity of the fluid and type of working fluid used. A correlation has been proposed for the temperature of these heat sources keeping in mind their strong dependence on the afore-mentioned parameters. It has been found that water can be used for better heat removal from the heat sources due to its high boiling point. The whole idea gives a clear insight to the electronic cooling engineers regarding the selection of working fluids and modes of heat transfer for the cooling of electronic components.

Appendices

Nomenclature

g :

acceleration due to gravity, 9.81 m/$\hbox {s}^{2}$

Gr :

Grashof number, $\dfrac{g \beta \Delta T L^3}{\nu ^2}$

h :

heat transfer coefficient, W/$\hbox {m}^{2}\hbox { K}$

k :

thermal conductivity, W/m K

L :

length of the heat source, m

q :

heat flux, W/$\hbox {m}^{2}$

$\textit{q}^*$ :

non-dimensional heat flux, $\dfrac{\Delta T_{ref}}{T_{\infty }}$

Q :

heat supplied, W

Re :

Reynolds number, $\dfrac{V L}{\nu ^2}$

Ri :

Richardson number, $\dfrac{Gr}{Re^2}$

T :

temperature, K

V :

velocity of fluid, m/s

$\textit{V}^*$ :

non-dimensional velocity, $\dfrac{V}{V_{max}}$

Greek symbols

$\beta$ :

isobaric thermal expansion coefficient of fluid, $\dfrac{1}{T_{mean}}$, $\hbox {K}^{-1}$

$\Delta T_{ref}$ :

reference temperature, $\dfrac{q L}{k_f}$, K

$\nu$ :

kinematic viscosity of fluid, $\hbox {m}^2$/s

$\theta$ :

non-dimensional temperature, $\dfrac{T_{max} - T_{\infty }}{\Delta T_{ref}}$

Subscripts

$\infty$ :

ambient

f:

fluid

max:

maximum