Enhanced heat transfer of heat sink channels with micro pin fin roughened walls

Synthetic jet actuators for heat transfer enhancement – A critical review

Enhancing heat transfer in air-cooled heat sinks using piezoelectrically-driven agitators and synthetic jets

An additively manufactured novel polymer composite heat exchanger for dry cooling applications

Heat transfer enhancement of air-cooled heat sink channel using a piezoelectric synthetic jet array

Piezoelectric translational agitation for enhancing forced-convection channel-flow heat transfer

Compared to traditional continuous jets, synthetic jets (jets with oscillatory flow such that the time-average velocity is zero) have specific advantages, such as lower power requirement, simpler structure and the ability to produce an unsteady turbulent flow that is known to be effective in augmenting heat transfer. This study presents experimental and computational results that document heat transfer coefficients associated with impinging a synthetic jet flow onto the tip region of a longitudinal fin used in an electronics cooling system. The effects of different parameters, such as amplitude and frequency of diaphragm movement and jet-to-cooled-surface spacing, are recorded. The computational results show a good match with experimental results. In the experiments, an actual-scale (1 mm jet orifice) system is introduced and, for finer spatial resolution and improved control over geometric and operational conditions, a large-scale mock-up (44 mm jet orifice) is applied in a dynamically-similar way, then tested. Results of the experiments at the two scales, combined with the computational results, describe fin heat transfer coefficients on and near the jet impingement stagnation point. A linear relationship for heat transfer coefficient versus frequency of diaphragm movement is shown. Heat transfer coefficient values as high as 650 W/m2K are obtained with high-frequency diaphragm movement. Cases with different orifice shapes show how jet impingement cooling performance changes with orifice shape.

An experimental and numerical study on heat transfer enhancement of a heat sink fin by synthetic jet impingement

Conventional heat sink systems with blowers or fans are approaching maximum thermal management capability due to dramatically increased heat dissipation from the chips of high power electronics In order to increase thermal performance of air-cooled heat sink systems, more active or passive cooling components are continually being considered One technique is to agitate of the flow in the heat sinks to replace or aid conventional blowers In the present study, an active heat sink system that is coupled with a piezoelectric translational agitator and micro pin fin arrays on the heat sink surfaces is considered The piezoelectric translational agitator generates high frequency and large displacement motion to a blade It is driven by an oval loop shell that amplifies the small displacement of the piezo stack actuator to the several-millimeter range The blade, made of carbon fiber composite, is easily extended to a multiple-blade system without adding much mass The micro pin fin arrays were created with the LIGA photolithography technique The cooling performance of the heat sink system was demonstrated in single-channel and multiple-channel test facilities The singlechannel test results show that the active heat sink with the agitator operating at a frequency of 686 Hz and peak-to-peak displacement of 14 mm achieved a low thermal resistance of 0053 C/W in a channel with a 79 m/sec flow velocity Different configurations of the translational agitator with multiple blades were fabricated and tested in a 26-channel, full-size heat sink Vibrational characteristics are also provided© 2012 ASME

An Active Heat Sink System With Piezoelectric Translational Agitators and Micro Pin Fin Arrays

A method is provided for heat transfer from a surface to a fluid. The method includes directing a first fluid flow towards the surface in a first direction and directing a second fluid flow towards the surface in a second direction. The first and second fluid flows cooperate to cool the surface.

Longzhong Huang

Papers

Heat transfer enhancement of air-cooled heat sink channel using a piezoelectric synthetic jet array

Piezoelectric translational agitation for enhancing forced-convection channel-flow heat transfer

An experimental and numerical study on heat transfer enhancement of a heat sink fin by synthetic jet impingement

An Active Heat Sink System With Piezoelectric Translational Agitators and Micro Pin Fin Arrays

Heat transfer apparatus and method