Author
Li, R., Gerstler, W. D., Arık, Mehmet, Vanderploeg, B.
Publication Date
2015-10-13
Publication Place
-
ASME
Subject
Temperature, Heat transfer, Cooling, Jets, Convection, Natural convection, Fins, Heat sinks, Air flow, Flow (Dynamics)
Type
Periodical
Language
English
Digital
Yes
Manuscript
No
Library
Özyeğin University
Library Asset ID
0022-1481
Record ID
af17c3f9-c668-4326-b029-86e5f30f69e1
Library Location
Mechanical Engineering
Date
2015-10-13
Notes
Due to copyright restrictions, the access to the full text of this article is only available via subscription.
Sample Text
Free convection air cooling from a vertically placed heat sink is enhanced by upward concurrent pulsated air flow generated by mesoscale synthetic jets. The cooling enhancement is experimentally studied. An enhancement factor is introduced and defined as the ratio of convection heat transfer coefficients for jet-on (enhanced convection) to jet-off (natural convection) cooling conditions. To obtain the two coefficients, heat transfer by radiation is excluded. A high-resolution infrared (IR) camera is used to capture detailed local temperature distribution on the heat sink surface under both cooling conditions. Analysis is carried out to obtain local convection heat transfer coefficients based on measured local surface temperatures. The enhancement of convectional cooling by synthetic jets can be then quantified both locally and globally for the entire heat sink. Two categories of thermal tests are conducted. First, tests are conducted with a single jet to investigate the effects of jet placement and orifice size on cooling enhancement, while multiple jets are tested to understand how cooling performance changes with the number of jets. It is found that the cooling enhancement is considerably sensitive to jet placement. Jet flow directly blowing on fins provides more significant enhancement than blowing through the channel between fins. When using one jet, the enhancement ranges from 1.6 to 1.9 times. When multiple jets are used, the heat transfer enhancement increases from 3.3 times for using three jets to 4.8 times for using five jets. However, for practical thermal designs, increasing the number of jets increases the power consumption. Hence, a new parameter, “jet impact factor (JIF),” is defined to quantify the enhancement contribution per jet. JIF is found to change with the number of jets. For example, the four-jet configuration shows higher JIF due to higher contribution per jet than both three-jet and five-jet configurations.
DOI
10.1115/1.4031647
Cilt
138
