The Effect of Orientation on the Performance of Small Free-Convection Heat Sinks for Use With a Thermoelectric Cryotherapy Device

2020 ◽  
Vol 13 (4) ◽  
Author(s):  
Mark Baldry ◽  
Victoria Timchenko ◽  
Chris Menictas
Keyword(s):  
Free Convection ◽  
Heat Sink ◽  
Rapid Development ◽  
Heat Sinks ◽  
Convection Heat ◽  
Pin Fin ◽  
Flat Base ◽  
Free Convection Heat ◽  
Performance Decline ◽  
Metal 3D Printing

Abstract The rapid development of metal 3D printing techniques has enabled the exploration of complex free-convection heat sink designs. Small free-convection heat sinks with pin-fin arrays (or novel geometries) are widely employed at different orientations in a variety of electronic devices, yet there is limited understanding of how orientation impacts their heat transfer behavior. This article characterizes the orientation-dependent performance of a small, tapered pin, free-convection heat sink (named HS17) manufactured with direct metal laser sintering for use with a thermoelectric scalp cryotherapy device for the prevention of chemotherapy-induced alopecia. A validated numerical model and custom-built free-convection test rig were used to investigate the heat sink’s performance over the orientation range of 0 deg to 135 deg. HS17 maintained relatively robust performance over the 0 deg to 90 deg range; however, the thermal resistance (Rth) at 112.5 deg and 135 deg was 6% and 11% higher compared to the 90 deg case, respectively. The heat sink design was modified to include a 22.5 deg wedge base (named HS17-W) to mitigate this performance decline, which is important to ensure safe and continued operation of the cryotherapy device. Compared to the flat base heat sink, the wedge-base design successfully reduced Rth from 11.9 K/W, 12.5 K/W, and 12.8 K/W to 11.5 K/W, 11.8 K/W, and 12.3 K/W at 90 deg, 112.5 deg, and 135 deg, respectively. These results demonstrate the effectiveness of the current proposed design to improve the performance of free-convection heat sinks at downward-facing orientations.

Pin-Fin Heat Sink With Horizontal Base and Blocked Edges

2008 ◽  
Author(s):  
D. Sahray ◽  
H. Shmueli ◽  
N. Segal ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Contact Resistance ◽  
Cross Section ◽  
Heat Input ◽  
Heat Sink ◽  
Numerical Study ◽  
Heat Sinks ◽  
Transfer Enhancement ◽  
Pin Fin

In the present work, horizontal-base pin fin heat sinks exposed to free convection in air are studied. They are made of aluminum, and there is no contact resistance between the base and the fins. For the same base dimensions the fin height and pitch vary. The fins have a constant square cross-section. The edges of the sink are blocked: the surrounding insulation is flush with the fin tips. The effect of fin height and pitch on the performance of the sink is studied experimentally and numerically. In the experiments, the heat sinks are heated using foil electrical heaters. The heat input is set, and temperatures of the base and fins are measured. In the corresponding numerical study, the sinks and their environment are modeled using the Fluent 6 software. The results show that heat transfer enhancement due to the fins is not monotonic. The differences between sparsely and densely populated sinks are analyzed for various fin heights. Also assessed are effects of the blocked edges as compared to the previously studied cases where the sink edges were exposed to the surroundings.

Thermal Analysis on Finned Heat Sink with Thin Porous Layers

2015 ◽  
Vol 764-765 ◽  
pp. 393-397
Author(s):  
Tzer Ming Jeng ◽  
Sheng Chung Tzeng ◽  
Dong Jhen Lin
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Heat Sink ◽  
Convection Heat Transfer ◽  
Thin Layers ◽  
Control Group ◽  
Convection Heat ◽  
Sintered Metal ◽  
Free Convection Heat ◽  
Radial Plate

This work experimentally explored the free convection heat transfer characteristics of finned heat sink with sintered-metal-beads layers. It has been proven that the metallic porous media can enhance the forced convection heat transfer efficiently. This work sintered the metal beads to adhere onto the both side surfaces of each radial plate fin of the metallic heat sink, and investigated whether the sintered-metal-beads layers promote the free convection heat transfer or not. The 0.5~0.85mm-diameetr bronze beads were employed. They were sintered smooth with the radial plate fins of the copper heat sink by thin layers at high temperature. The experimental groups were the plate-shape sintered-metal-beads and strip-shape sintered-metal-beads heat sinks. The pure copper finned heat sink was set as the control group. The results demonstrated that the thermal resistances of the experimental groups were separately 20.7% and 11.6% higher than that of the control group at the smaller temperature difference between the heated surface and the ambient (△T≈30°C); while the thermal resistances of the experimental groups were separately 15.3% and 6.9% higher than that of the control group at △T≈60°C. In general, the present sintered-metal-beads layers cannot strengthen the free convection heat transfer.

Effect of Fin Pitch and Height on Pin-Fin Heat Sink Performance

2008 ◽  
Author(s):  
D. Sahray ◽  
H. Shmueli ◽  
N. Segal ◽  
G. Ziskind ◽  
R. Letan
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Contact Resistance ◽  
Cross Section ◽  
Heat Input ◽  
Heat Sink ◽  
Numerical Study ◽  
Heat Sinks ◽  
Transfer Enhancement ◽  
Pin Fin

In the present work, horizontal-base pin fin heat sinks exposed to free convection in air are studied. They are made of aluminum, and there is no contact resistance between the base and the fins. The sinks have the same base dimensions whereas the fin height and pitch vary. The fins have a constant square cross-section. The effect of fin height and pitch on the performance of the sink is studied experimentally and numerically. In the experiments, the heat sinks are heated using foil electrical heaters. The heat input is set, and temperatures of the base and fins are measured. In the corresponding numerical study, the sinks and their environment are modeled using the Fluent 6.3 software. The results show that heat transfer enhancement due to the fins is not monotonic. The differences between sparsely and densely populated sinks are analyzed for various fin heights.

EXPERIMENTAL STUDY OF FREE CONVECTION HEAT TRANSFER IN THE POROUS METAL-FOAM HEAT SINK

2013 ◽  
Vol 37 (3) ◽  
pp. 841-850 ◽  
Author(s):  
Tzer-Ming Jeng ◽  
Sheng-Chung Tzeng ◽  
Zhi-Ting Yeh
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Metal Foam ◽  
Convection Heat Transfer ◽  
Porous Metal ◽  
Metal Foams ◽  
Heat Sinks ◽  
Convection Heat ◽  
Pore Density ◽  
Free Convection Heat

This study experimentally investigated the free convection heat transfer characteristics of the annular metal-foam heat sinks. The results showed that the heat transfer coefficient (h) decreased as the pore density of metal foams increased when the thickness (tc) of the annular metal foams equaled 5 mm, but the (h) increased as the pore density increased when tc = 11 and 14.5 mm. Besides, the (h) increased firstly and then decreased as (tc) increased. There was better heat transfer effect when tc = 11 mm in the present study.

Experimental and Numerical Analysis of Convective Heat Transfer From Notched Fin Arrays With Pin Fins

2013 ◽  
Author(s):  
Sunil V. Dingare ◽  
Suneeta S. Sane ◽  
Aniket H. Kawade ◽  
Hrishikesh N. Kulkarni ◽  
Kaustibh U. Suranglikar
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Temperature Difference ◽  
Heat Sink ◽  
Convection Heat Transfer ◽  
Heat Sinks ◽  
Central Portion ◽  
Pin Fin ◽  
Pin Fins ◽  
Free Convection Heat

In electronic components, it is essential to provide for adequate cooling to ensure that overheating does not affect the performance. It has been observed that for short fins, (L/H ≤ 5) due to formation of stagnant zone, central portion of fin is ineffective. To overcome this problem central portion from plate fin is removed. By doing so average heat transfer coefficient of notched array was improved almost by 30percentage compared to normal plate fin array. In this study we present computational assessment of notched plate fin heat sink (NPFHS) & notched plate fin pin fin heat sink (NPFPFHS). Based on NPFHS, a NPFPFHS is constructed which is composed of a NPFHS and some columnar pins planted between notched plate fins. Limited experimentation is carried out for validation of numerical model. Numerical analysis is carried out to compare thermal performance of these two types of heat sinks under the condition of equal temperature difference between mean sink temperature and ambient temperature. The effects of fin spacing, fin height, pin fin diameter and temperature difference between fin and surroundings on the free convection heat transfer from horizontal fin arrays were studied. The analysis have been carried out for the two types of heat sinks with three different spacing, three different height, four temperature differences and three pin diameters.

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