Oscillating Heat Pipe Thermal Performance and Stability Limits

The effective thermal conductivity of an oscillating heat pipe was measured using a system that was first validated by measuring materials with known thermal conductivity (aluminum and copper). The oscillating heat pipe was constructed of aluminum; used ammonia as the working fluid; and was designed for stable operation from 10W and 20°C to 100W and 75°C. Results showed the oscillating heat pipe had effective thermal conductivity as high as 2400 W /mK with input powers ranging from ~ 10–110 W. Above and below the prescribed operating range, the oscillating heat pipe encountered unstable conditions and its effective thermal conductivity decreased.