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ABSTRACT
Flow boiling experiments were conducted in a staggered array micro pin fin channel heat sink with deionized water for two-phase pressure drop and boiling heat transfer at constant heat flux. Micro pin fin is a diameter of 400 μm, height of 700 μm and spacing of 300 μm on copper heat sink. From the experimental results, at a vapor quality up to 0.043, the boiling heat transfer found to decrease as the vapor quality increased. The heat transfer coefficient is dependent on the mass flux and the pressure drop increased with the increase in mass flux.
Nomenclature
| Ac | = | Cross-sectional area of micro pin-fin |
| Af | = | Area of the fin surface |
| At | = | Total heat transfer surface area |
| Bo | = | Boiling number |
| Cp | = | Specific heat |
| d | = | Diameter of fin |
| dh | = | Channel clearance |
| f | = | Friction factor |
| G | = | Mass flux |
| g | = | Gravitational acceleration |
| H | = | Fin height |
| h | = | Heat transfer coefficient |
| i | = | Enthalpy |
| k | = | Thermal conductivity |
| L | = | Length |
| MAE | = | Mean absolute error |
| MR | = | Mean ratio |
| mfin | = | Fin parameter |
| 555 | = | Mass flow rate |
| N | = | Number of axial direction fins |
| Nu | = | Nusselt number |
| Pfin | = | Cross-sectional perimeter of micro pin-fin |
| △P | = | Pressure drop |
| Pr | = | Prandtl number |
| Q | = | Amount of heat |
| q” | = | Heat flux |
| Re | = | Reynolds number |
| S | = | Pitch |
| T | = | Temperature |
| u | = | Velocity |
| We | = | Weber number |
| X | = | Martinelli parameter |
| x | = | Quality |
Greek
| δ | = | Length between the channel wall and the channel surface |
| η | = | fin efficiency |
| ηt | = | total efficiency |
| μ | = | Viscosity |
| v | = | Specific volume |
| ρ | = | Density |
| σ | = | Surface tension |
| 2 | = | Two-phase multiplier |
Subscripts
| ch | = | Channel |
| copper | = | Copper |
| corr | = | Correlation |
| D | = | Diagonal direction |
| e | = | Exit |
| exp | = | experimetal data |
| f | = | Liquid |
| fin | = | Fin |
| g | = | Vapour |
| heater | = | Thin film heater |
| in | = | Inlet |
| L | = | Axial direction |
| local | = | Local |
| loss | = | Loss |
| max | = | Maximum |
| mean | = | Mean temperature |
| nb | = | Nucleate boiling |
| out | = | Outlet |
| sat | = | Saturation |
| sp | = | Single phase |
| sub | = | Subcool |
| surf | = | Channel surface |
| T | = | Transverse direction |
| tp | = | Two-phase |
| w | = | Channel wall |