Pulsating Heat Pipe
Novel phase-change technology utilizing oscillating capillary loops. Perfect for highly compact, high-density systems under dynamic thermal loads.
The Pulsating Heat Pipe (PHP), also known as Oscillating Heat Pipe (OHP), is a passive two-phase heat transfer device with no wick structure and no external power supply. A meandering capillary tube (0.5–3 mm inner diameter, copper or aluminum) is evacuated and partially filled (40–60% volume) with a working fluid. Surface tension creates alternating liquid slugs and vapor plugs that oscillate autonomously via thermal pressure gradients.
PHP coolers operate stably in any orientation — including microgravity — and show improved anti-gravity performance as heat load increases. Thermal performance surpasses copper vapor chambers at significantly lower weight. Any bending shape can be freely chosen without affecting thermal conductivity — ideal for compact, complex device geometries.
Specifications
- Cooling Principle
- Self-excited oscillating two-phase pulsation process (Pulsating Heat Pipe)
- Technology
- Meandering capillary loop (0.5–3.0 mm ID) | no wick structure | self-oscillating
- Materials
- Copper or aluminum (capillary tube) | custom geometry (flex-routing)
- Working Fluid
- Water | Ethanol | Liquid ammonia | Refrigerant and others (application-dependent)
- Tube Diameter
- 0.5–3.0 mm inner diameter (copper or aluminum)
- Anti-Gravity Performance
- Improves with heat load — orientation-independent & microgravity-capable
- Bend Flexibility
- Any routing shape without impact on thermal conductivity
- Response Time
- Near-instantaneous thermal response (< 1 second)
- Applications
- Aerospace & Satellite, EV Batteries, AI Servers, High-Power LED, Industrial
Working Principle
- Evaporation & Pressure Build-Up: Heat at the evaporator vaporizes the fluid. Expanding vapor plugs push liquid slugs toward the condenser.
- Condensation & Pressure Drop: Vapor condenses in the cooler condenser, contracts, and creates low pressure — forming a gradient back toward the evaporator.
- Self-Sustained Pulsation: The pressure gradient drives continuous oscillation — in any orientation, including microgravity. No pump, no moving parts.
- Continuous Heat Transfer: The temperature difference sustains the cycle continuously. Liquid slugs act as heat carriers, achieving extremely high effective thermal conductivity.