Barrier-Separated Two-Phase Heat Transfer for High Heat Flux Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cooling technologies struggle to efficiently manage high heat fluxes exceeding 200 W/cm² in electronic devices like GaN HEMTs, leading to thermal management challenges such as mechanical stress, limited heat flux capability, flow instabilities, and device failure due to hotspots and high pumping power.
Innovation Solution
A hybrid two-phase cooling system using a capillary-driven evaporative cooling mechanism with a mechanically pumped two-phase loop, incorporating a non-permeable barrier to separate vapor and liquid phases, and optimized wick structures for enhanced heat transfer, utilizing AlN substrates and dielectric materials to maintain temperature uniformity and reduce thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional cooling technologies are used, then device simplicity is maintained, but heat flux removal capability is insufficient for high heat fluxes exceeding 200 W/cm²
Solution Approach 1:
The cooling system is segmented into distinct functional zones: a first chamber containing liquid coolant and a wick structure, and a second chamber containing vapor. The non-permeable barrier separates these chambers, allowing independent optimization of each zone for maximum heat flux removal capability while maintaining manageable system complexity through modular design.
Solution Approach 2:
The system utilizes phase transitions of the coolant (liquid to vapor in the wick structure, vapor condensation in the second chamber) to achieve efficient heat flux removal exceeding 200 W/cm². This two-phase heat transfer mechanism provides high heat transfer coefficients that conventional single-phase cooling cannot achieve.
2Power
If microchannel two-phase cooling is used, then large heat removal is achieved, but flow instabilities cause dry-out and hot spots
Solution Approach 1:
By segmenting the cooling system into separate liquid and vapor chambers divided by a non-permeable barrier, the invention eliminates flow instabilities associated with microchannel two-phase cooling. The liquid chamber maintains stable liquid supply through capillary action in the wick, while the vapor chamber safely contains and condenses vapor, preventing dry-out and hot spots.
Solution Approach 2:
The non-permeable barrier acts as an intermediary between the liquid and vapor phases, allowing heat transfer while preventing direct fluid interaction. This mediator enables stable two-phase operation without the flow instabilities that plague microchannel systems, as the barrier prevents vapor lock and liquid hammer effects.
3Temperature
If vapor chamber is used, then excellent heat spreading and isothermal performance are achieved, but it cannot operate between alternating heat sources and heat sinks
Solution Approach 1:
The system incorporates dynamic adaptability by allowing the heat transfer device to operate between alternating heat sources and heat sinks. The pump can reversibly circulate coolant between different heat sources and the heat sink, enabling the system to adapt to changing thermal loads while maintaining isothermal performance through efficient two-phase heat transfer.
Solution Approach 2:
The cooling system is designed with universal functionality to handle multiple heat sources and operate in different configurations. The same device can cool alternating heat sources by reversing pump operation, and the two-phase heat transfer mechanism maintains excellent temperature uniformity across all operational modes.
4Power
If microchannel liquid cooling is used, then large heat removal is achieved, but large pumping power is required
Solution Approach 1:
The wick structure in the liquid chamber provides self-service cooling through capillary action, which passively transports liquid without requiring external pumping power. This eliminates the large pumping power requirements of microchannel liquid cooling while maintaining large heat removal capability through the two-phase heat transfer process.
Solution Approach 2:
The invention replaces the mechanical pumping system with a passive capillary-driven liquid transport mechanism. The wick structure uses capillary forces to circulate liquid through the heat transfer device, substituting mechanical energy input with surface tension-driven flow, thereby eliminating large pumping power requirements while achieving efficient heat removal.
5Power
If heat sources are cooled alternately between two substrates, then heat flux removal is achieved, but the distance between substrates must be minimized for compactness
Solution Approach 1:
The pump acts as an intermediary that enables efficient heat flux removal between substrates separated by larger distances. By actively circulating coolant between the heat sources and heat sink, the pump compensates for the increased thermal resistance over longer distances, allowing compact design without sacrificing heat transfer performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively transports large amounts of heat over long distances with low thermal resistance, maintains isothermal conditions, operates at different gravity orientations, and reduces pumping power, thereby stabilizing two-phase flow and preventing device failure.
Implementation Method 1
a wick structure secured to an inner surface of at least one substrate, a first portion of the wick structure positioned in the first chamber, and a second portion of the wick structure positioned in the second chamber and interconnecting in passive liquid communication with the first portion
Implementation Method 2
hybrid two-phase cooling system using a capillary-driven evaporative cooling mechanism
Implementation Method 3
a hybrid two-phase cooling system using a capillary-driven evaporative cooling mechanism with a mechanically pumped two-phase loop
Implementation Method 4
incorporating a non-permeable barrier to separate vapor and liquid phases
Implementation Method 5
utilizing AlN substrates and dielectric materials to maintain temperature uniformity and reduce thermal resistance
Data Source
AI summary
A heat transfer device includes a hollow spacer between opposed substrates, defining an enclosure, at least one of the substrates adapted to be secured to at least one heat source. A non-permeable barrier is in the enclosure between the substrates. A first chamber inside the enclosure is defined by the spacer, the substrates, and the barrier, the first chamber in fluid communication with at least one first inlet and first outlet. A second chamber inside the enclosure and outside the first chamber and is defined by the spacer, the substrates, and the barrier, the second chamber in fluid communication with at least one second outlet. A wick structure is secured to at least one substrate, a first portion of the wick structure in the first chamber, and a second portion of the wick structure in the second chamber and interconnecting in passive liquid communication with the first portion.