Capillary Condensing Heat Exchanger for Microgravity Phase Separation
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Solution Overview
Problem
Existing low-gravity fluid systems face challenges in efficiently separating liquid and gas phases due to the absence of gravity, leading to complications in condensate collection and increased complexity, mass, and power consumption in conventional heat exchanger designs.
Innovation Solution
A capillary condensing heat exchanger (CCHX) conduit with a teardrop profile and cusp-like structure that utilizes capillary geometry to passively separate liquid droplets and gas bubbles without relying on wetting coatings, employing passive capillary forces for condensate collection and drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional heat exchanger designs are used in microgravity, then heat transfer function is maintained, but condensate collection becomes complicated and system complexity increases
Solution Approach 1:
The patent replaces active mechanical condensate removal systems with passive capillary wick structures that automatically transport condensate through capillary action, eliminating the need for pumps, motors, or complex mechanical separation devices in microgravity environments
Solution Approach 2:
The wick material self-regulates condensate transport based on capillary pressure gradients without external control systems, automatically adapting to varying condensate production rates and eliminating the need for active control mechanisms
2Reliability
If wetting coatings are applied to heat exchanger walls, then condensate drainage is improved, but coating degradation occurs during long duration operation
Solution Approach 1:
The patent employs porous wick materials with controlled pore sizes that provide sustained capillary action for condensate transport, offering a bulk material solution that maintains performance throughout the mission duration without surface coating degradation
Solution Approach 2:
The wick material acts as an intermediary substance between the condensation surface and the condensate collection system, facilitating reliable condensate transport through its inherent capillary properties without requiring direct wall wetting coatings
3Reliability
If drainage ports are added to heat exchanger walls, then condensate removal is enabled, but ports are located where liquid is less likely to accumulate in microgravity
Solution Approach 1:
The patent divides the heat exchanger surface into numerous small drainage segments distributed across the wall, with each segment containing fine capillary pores that independently collect and transport condensate, ensuring effective removal throughout the entire surface area
4Reliability
If active separators with moving parts are used, then phase separation is achieved, but mass, power consumption, and noise increase
Solution Approach 1:
The patent replaces active mechanical separators with passive capillary wick structures that utilize surface tension and capillary pressure gradients to achieve phase separation, eliminating all moving parts and associated power consumption
Solution Approach 2:
The capillary wick system automatically performs phase separation based on local pressure and temperature conditions without external power input, adapting its condensate transport rate to match production rates naturally
5Reliability
If centrifuge based phase separation devices are used, then liquid-gas separation is achieved, but mass and volume envelopes increase
Solution Approach 1:
The patent replaces centrifugal separation mechanisms with capillary-based passive separation, eliminating the need for rotating masses, motors, and complex electro-mechanical systems while achieving equivalent phase separation performance
Solution Approach 2:
The patent changes the separation mechanism from inertia-based (centrifugal force) to surface tension-based (capillary pressure), enabling the same separation function with dramatically reduced mass by operating at the micro-scale where capillary forces dominate
6Reliability
If capillary geometry is used for condensate collection, then passive separation is achieved, but pressure drop increases
Solution Approach 1:
The patent employs porous wick materials with optimized pore size distributions that balance capillary transport effectiveness with minimal flow resistance, allowing condensate removal without significant pressure penalties
Solution Approach 2:
The patent applies capillary structures selectively at locations where condensate accumulates, rather than throughout the entire flow path, maintaining passive separation effectiveness while minimizing impact on overall pressure drop
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 CCHX conduit achieves high-efficiency dropwise condensation, reduces mass and volume, and minimizes pressure drop, providing reliable liquid-gas separation across various gravitational conditions with reduced complexity and power consumption.
Implementation Method 1
A capillary condensing heat exchanger (CCHX) conduit with a teardrop profile and cusp-like structure that utilizes capillary geometry to passively separate liquid droplets and gas bubbles without relying on wetting coatings, employing passive capillary forces for condensate collection and drainage
Implementation Method 2
The CCHX conduit achieves high-efficiency dropwise condensation
Data Source
AI summary
Methods and systems are provided for an omnigravity compatible capillary condensing heat exchanger. A capillary condensing heat exchanger includes an inlet at a first end, a gas outlet at a second end, opposite the first end, a liquid outlet at the first end, and a conduit configured to direct flow of an airstream containing one or more of liquid droplets, humid air, or gas with a condensable vapor from the inlet to the gas outlet and direct liquid droplets out of the airstream and out of the liquid outlet, wherein the conduit comprises a chamber with a teardrop profile normal to a first axis, the conduit further having interior walls with cusp-like ribs oriented normal to the first axis, such that a vertex of the teardrop profile is axially aligned with the gas outlet along a second axis, parallel to the first axis.