Variable Diodicity Fluid Diodes for Two-Phase Flow Control
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Solution Overview
Problem
Microchannel two-phase cooling systems experience fluid backflow due to boiling instabilities, which deteriorates cooling performance in heat-generating devices like power electronics.
Innovation Solution
Incorporating a fluid diode array with varying diodicities at the channel inlets of heat sink fluid channels to preferentially direct the cooling fluid flow forward and prevent backflow, with higher diodicity fluid diodes positioned near the center of the cooling manifold where boiling instabilities are most pronounced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two-phase cooling is used to increase heat transfer capacity, then heat transfer efficiency is improved, but fluid backflow occurs due to boiling instabilities
Solution Approach 1:
Fluid diodes are introduced as intermediary components between the heat source and heat sink channels. These diodes act as mediators that permit forward flow while blocking backflow caused by boiling instabilities, thus resolving the contradiction between maintaining high heat transfer capacity and ensuring flow stability in two-phase cooling systems
Solution Approach 2:
Fluid diodes with varying diodicity values are strategically positioned at different locations within the cooling manifold. The diodicity of each fluid diode is tailored to the local boiling characteristics and heat flux conditions at its specific position, creating locally optimized flow control that maintains system-wide stability while preserving overall heat transfer efficiency
2Ease of manufacture
If uniform fluid diodes are used throughout the cooling manifold, then manufacturing is simplified, but flow distribution becomes suboptimal due to varying local conditions
Solution Approach 1:
The patent implements fluid diodes with non-uniform diodicity values distributed throughout the cooling manifold. Each fluid diode's diodicity is specifically selected to match the local thermal and hydraulic conditions at its position, such as local heat flux, boiling intensity, and channel geometry. This local optimization ensures that each diode provides appropriate flow control for its specific location, maximizing overall cooling efficiency while the modular diode design keeps manufacturing feasible through standardized components with varying geometric parameters
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 fluid diode array effectively restricts backflow, enhancing the cooling performance and efficiency of the microchannel two-phase cooling system by ensuring consistent heat transfer from heat-generating devices.
Implementation Method 1
Cooling fluid may be used to receive heat generated by the heat-generating device by convective thermal transfer, and remove such heat from the heat-generating device
Implementation Method 2
the cooling fluid is allowed to boil such that heat may be stored in the latent heat of the cooling fluid
Implementation Method 3
heat may be stored in the latent heat of the cooling fluid
Implementation Method 4
Two-phase cooling devices use a cooling fluid at or near saturation such that, as heat is removed from the heat-generating device, the cooling fluid is allowed to boil
Data Source
AI summary
A microchannel two-phase cooling apparatus includes a cooling manifold and a fluid diode array. The cooling manifold includes one or more fluid inlets, one or more fluid outlets, and a plurality of fluid channels extending between and fluidly coupling the one or more fluid inlets and the one or more fluid outlets. The fluid diode array includes a plurality of fluid diodes positioned within the cooling manifold. Individual fluid diodes of the fluid diode array are fluidly coupled to individual fluid channels. The fluid diode array includes a first set of fluid diodes having a first average diodicity and a second set of fluid diodes having a second average diodicity. The first average diodicity is greater than the second average diodicity and each individual fluid diode of the first set of fluid diodes has a greater diodicity than any individual fluid diode of the second set of fluid diodes.