ABSTRACT
High processing demand has started high heat generation problems inside compact electronic components. In this work, firstly the thermal performance was investigated experimentally for the mini channel having slots on straight rectangular fin heat sink. Slots were made which reinitialize the thermal boundary layer at each slot position. This effect makes the flow again in a developing state and helps in a better mixing of the flow inside the channel due to the presence of vortexes because of slots, which overall results in better heat transfer. The thermal performance of the slotted fin heat sink was compared to the straight rectangular fin heat sink. Secondly, TiO2-pure water (0.005% and 0.01%) which was the blend of Anatase and Rutile crystalline-shaped nanoparticles were used both numerically and experimentally. The base temperature was reduced 8.2% using pure water at 1LPM when compared with the straight rectangular fin heat sink reported in the literature. The lowest base temperature recorded for the slotted fin heat sink was found to be 40.25°C using TiO2-pure water (0.01%) nanofluids at 1 LPM. The reduction in base temperature observed for TiO2 -H2O (0.005%) and TiO2-pure water (0.01%) was 8.8% and 11%, respectively, as compared to pure water. Experimental results were numerically validated with good agreement.
Disclosure statement
No potential conflict of interest was reported by the authors.
Nomenclature
w_s | = | heat sink width in mm |
l_s | = | heat sink length in mm |
l_f | = | fin length in mm |
t_f | = | Fin thickness in mm |
S_t | = | Thickness of slot in mm |
h_b | = | Heat sink base height in mm |
h_f | = | Fin height in mm |
h | = | height of nozzle from base in mm |
H | = | collective height in mm |
l_c | = | Chip length in mm |
t_c | = | Chip thickness in mm |
l_t | = | Overall length in mm |
f_s | = | spacing between fins in mm |
C_nf | = | Specific heat for nanofluids in kJ/kgK |
C_np | = | Specific heat for nanoparticles in kJ/kgK |
C_bf | = | Specific heat of base fluid in kJ/kgK |
= | Nanofluids thermal conductivity in W/mK | |
= | Nanoparticles Thermal conductivity in W/mK | |
= | Base fluid Thermal conductivity in W/mK | |
L.M.T.D | = | Log of mean temperature difference in 0C |
L.P.M | = | Liters per minute |
ṁ | = | Mass flow rate in kg/s |
Q | = | Heat transfer rate in W |
Q | = | Volumetric flow rate in LPM |
R_th | = | Thermal resistance in 0C/W |
T_b | = | Temperature at base in 0C |
T_i | = | Inlet Temperature in 0C |
T_o | = | Outlet Temperature in 0C |
W_np | = | Nanoparticles weight fraction |
W_bf | = | Base fluid weight fraction |
∅ | = | Volume fraction |
p_bf | = | Base fluid density in kg/m3 |
p_np | = | Nanoparticles density in kg/m3 |
p_nf | = | Nanofluids density in kg/m3 |
= | Dynamic viscosity of nanofluids in kg/ms | |
= | Dynamic viscosity of base fluid in kg/ms | |
= | Density of mixture in kg/m3 | |
V_m | = | Velocity of mixture in m/s |
= | mixture viscosity in kg/ms | |
Re_P | = | Reynolds number for primary phase |
K_t | = | Thermal conductivity for turbulent phase in W/mK |
H_K | = | Enthalpy for K-phase in kJ/kg |
K_m | = | Thermal conductivity for k-phase in W/mK |
= | nanoparticle volumetric concentration | |
= | volumetric concentration for k-phase | |
= | velocity for secondary phase in m/s | |
= | velocity for primary phase in m/s | |
= | drift velocity for k-phase in m/s |