Under an ongoing NASA SBIR Phase II Program, a Pulsating Heat Pipe (PHP) based plate heat spreader is being developed for electronics cooling. A 3U form factor electronics card cover of size 160 mm x 100 mm x 3.38 mm was selected for developmental efforts. A PHP plate with sub-surface (internal) fluid channels was fabricated with aluminum T6-6061. The PHP plate was charged with propylene and the performance was determined and compared with the conduction plate at various operating conditions like operating temperatures, fluid fill ratio, and orientation. It was determined that the propylene-charged PHP can deliver up to 240 W (heat flux: 37.2 W/cm2) when the condenser is maintained at an operating temperature of 0° C and -10° C. Along with propylene, the PHP is being tested with other working fluids like R1233zd(e), toluene, and ammonia. In addition to performance determination, other developmental efforts involving space qualification testing of the PHP plate heat spreader are being undertaken.
Hota et al. (Sun,) studied this question.