BS in Mechanical Engineering
Mechanical Engineering Department
Advancements in electronics have created the need for improved cooling standards. The AECM standard, created to replace the antiquated ARINC 600 specification for aircraft, draws inspiration from a cooling specification known as VITA 48.2. The ARINC standard is in early stages of development and this project researches the feasibility of using air as a convective fluid instead of a liquid, the fluid used in the VITA specification.
A performance factor calculated from the ratio of the heat dissipated by convective heat exchanger plates over the power used to cause forced convective flow over said plates helps to quantify the effectiveness of various cooling scenarios.
Design development of the heat exchangers resulted in a plan to manufacture and test six different heat exchanger configurations. Five of these used various assortments of porous foam aluminum; the sixth used a more conventional finned design. To house and test the effectiveness of these configurations a testing platform was created to control and measure appropriate testing values. Before each configuration was tested, the setup was sealed to prevent leaks and insulated to minimize heat transfer sources beyond the effects of the controlled and measured convective air.
Notable results include a 10ppi, 8% density porous aluminum foam heat exchanger which resulted in both the largest pressure drop, 2.7 inches of water and heat dissipated at 301 watts at a flow rate of 72 CFM. The performance factor of this plate was the lowest at 13 [Watts/Watts]. Conversely, the largest performance factor at similar flow rate was seen in the finned plate design as 58 [Watts/Watts] at 71 CFM. However, its heat transfer for this flow rate was 167 Watts. Test results and analysis for each prototype is given within the report. A general plot of the results provides a valuable selection tool for choosing an appropriate starting design point to develop AECM air cooling for Boeing.
The heat dissipation seen from the air cooled heat exchanger plates is competitive with the liquid cooled module plates and deserves further investigation. The added benefits of natural convection and the weight savings of air cooling further endorse this conclusion.