An electronics component manufacturer was seeking new advanced cooling solutions for an optical device. The current cooling solution of a thermally conductive and optically clear film coupled with a copper spreader and a liquid-cooled cold plate was not capable of accommodating the increasing waste heat dissipation requirements while utilizing decreasing space. ACT was tasked with evaluating the feasibility of spray impingement solution to meet these next generation cooling requirements. Both single and two phase options were reviewed, modeled and tested. Different fluids, nozzle and nozzle angles were evaluated and tested at various temperature conditions provided by the client. The sketch of the test assembly used to obtain heat transfer coefficients and other measurements is shown below. Also shown is a modeled thermal image of the junction area (hottest location) observed on the optical device. These results showed that the high heat transfer coefficients obtained with impingement, combined with efficient heat spreading in the optical device produced a gradient across the device that easily met the design requirements. The study concluded that both the single and two phase impingement cooling solutions could feasibly meet the design requirements. Although the two phase approach offers improved thermal performance over the single phase design, due to the more complex technology development and system structure of the two phase approach, for this application ACT recommended the single phase cooling solution.

Sketch of test assembly with heater surface facing downward as positioned during testing.

The hottest area in the model is the fireball heater in the corner of the thermal test vehicle. The junction side of this area is magnified in this plot. Temperature gradients were within the design requirements.