Research Overview: Passive Two-Phase Thermal Management Systems

Driving High-Heat-Flux Dissipation Without External Pumping

Modern high-performance electronics, aerospace payloads, space radiators, and energy systems generate concentrated heat fluxes often exceeding 100 W/cm². Active pumped liquid loops introduce parasitic power draw, vibration, weight penalties, and mechanical failure risks.

My research investigates the design, microscale engineering, hydrodynamics, and experimental validation of passive two-phase thermal management devices. By leveraging liquid-vapor phase change and capillary/oscillatory driving forces, our work targets high heat transport capacity, low thermal resistance, rapid startup, and robust operation across variable gravitational orientations.

Miniature Loop Heat Pipes

The Engineering Objective: Enable long-distance, high-capacity heat transport with zero moving parts and flexible transport lines for satellite avionics, radar T/R modules, and constrained electronic enclosures.

Architectural Innovations: Development and experimental characterization of integrated flat-evaporator architectures where the evaporator and condenser are thermally coupled or disposed on a single compact base plate to minimize interfacial thermal resistance.

Transient & Operational Physics:

Investigating startup dynamics at low and ultra-high heat loads, minimizing temperature overshoot.
Mitigating vapor back-penetration and parasitic heat leak from the evaporator core to the compensation chamber (CC).
Evaluating operational limits: capillary limit, boiling limit, and dryout hysteresis under adverse tilt angles.

Flat Pulsating Heat Pipes

The Engineering Objective: Develop lightweight, wickless thermal spreaders capable of managing multi-source, transient heat loads with minimal thermal resistance.

Hydrodynamic Phenomena:

Characterizing self-sustained thermally driven oscillations of liquid slugs and vapor plugs inside capillary channels.
High-speed visualization of flow pattern transitions: from bubbly and slug/plug flow to semi-annular and annular film evaporation.

Parametric Optimization:

Volumetric Filling Ratio (FR): Quantifying dryout thresholds at low filling ratios versus sensible-heat domination at high filling ratios.
Working Fluids: Performance benchmarking using deionized water, ethanol, acetone, and self-rewetting binary mixtures.
Orientation & Gravity Independence: Mitigating gravity-dependent performance degradation through closed-loop serpentine topologies and asymmetric channel designs.

Grooved Heat Pipes

The Engineering Objective: Maximize effective thermal conductivity along structural bus bars and space radiator panels with near-zero liquid pressure drop.

Capillary Channel Mechanics:

Investigating thin-film evaporation and meniscus recession along micro-grooves (rectangular, trapezoidal, and re-entrant profiles).
Modeling the balance between capillary pumping head and viscous pressure loss in the liquid return path.

Operational Limits:

Determining entrainment and shear limits where high-velocity counter-current vapor flow strips liquid from open groove tips.
Evaluating grooved heat pipe performance under zero-g / microgravity environments and varying inclination angles.

Advanced Biporous Wick Engineering

The Capillary-Permeability Trade-off: Conventional monoporous wicks face a fundamental constraint: fine pores generate high capillary head but impose severe hydraulic flow resistance, inducing premature dryout at high heat fluxes.

Dual-Pore Transport Mechanism:

Micropores (< 5 µm): Provide intense capillary suction to maintain continuous liquid feed to the evaporating meniscus.

Macropores (40–100 µm): Act as low-resistance escape arteries for generated vapor, drastically delaying boiling incipience inside the core and enhancing the Critical Heat Flux (CHF).