Effect of nanofluid on thermo hydraulic performance of double layer tapered microchannel heat sink used for electronic chip cooling

ABSTRACT

Thermo-hydraulic performance analysis of a tapered double layer microchannel heat sink (DL-MCHS) is done numerically. Water and Al₂O₃–H₂O nanofluid coolants are used with uniform heat flux at the base of DL-MCHS. Comparatively higher heat transfer and lower pressure drop can be achieved considering temperature dependent thermo-physical properties. An overall performance factor is determined which indicates that though the tapered channel gives better thermal performance than straight channel, it is not always advantageous, if hydraulic performance is also considered, due to the increase in pressure drop penalty. Finally, from optimization study, maximum heat transfer is obtained at tapering factor of 0.32.

Nomenclature

A	=	area (m2)
cp	=	specific heat (J kg−1 K−1)
d	=	diameter (m)
Eu	=	Euler number
H	=	height of DL-MCHS (m)
h	=	height of channel (m)
	=	mean heat transfer coefficient
k	=	thermal conductivity (W m−1 K−1)
L	=	length of DL-MCHS (m)
Nu	=	Nusselt number
Pf	=	performance factor
Pr	=	Prandtl number

Greek symbols
µ	=	dynamic viscosity (Pa.S)
ρ	=	density (kg m−3)

Subscript
f	=	fluid
in	=	inlet
nf	=	nanofluid
out	=	outlet
p	=	particle
s	=	solid

Nomenclature

A	=	area (m2)
cp	=	specific heat (J kg−1 K−1)
d	=	diameter (m)
Eu	=	Euler number
H	=	height of DL-MCHS (m)
h	=	height of channel (m)
	=	mean heat transfer coefficient
k	=	thermal conductivity (W m−1 K−1)
L	=	length of DL-MCHS (m)
Nu	=	Nusselt number
Pf	=	performance factor
Pr	=	Prandtl number

Greek symbols
µ	=	dynamic viscosity (Pa.S)
ρ	=	density (kg m−3)

Subscript
f	=	fluid
in	=	inlet
nf	=	nanofluid
out	=	outlet
p	=	particle
s	=	solid