Packed Manifold Heat Exchanger for Stable Two-Phase Refrigerant Flow
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Solution Overview
Problem
Current heat exchangers, particularly in refrigeration systems, face inefficiencies in two-phase flow environments, leading to poor heat transfer coefficients, increased pressure drop, and freeze-out conditions, especially at ultra-low and cryogenic temperatures, due to inadequate phase distribution and surface area-to-volume ratios.
Innovation Solution
A heat exchanger design incorporating a packed distributor within the manifold, featuring packing elements such as spherical or cylindrical elements, which improves fluid distribution and reduces pressure drop across the exchanger, while maintaining a high heat transfer coefficient, even at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If plate type heat exchangers are used to increase surface area to volume ratio, then compactness is improved, but two-phase flow distribution deteriorates leading to poor heat transfer coefficients and increased pressure drop
Solution Approach 1:
A packed distributor is introduced as an intermediary component within the manifold of the plate type heat exchanger. This packing material (such as random packing elements or structured elements) acts as a mediator to improve two-phase flow distribution before the fluid enters the heat transfer channels, thereby maintaining compactness while resolving the flow distribution issues
Solution Approach 2:
The invention utilizes porous packing materials within the manifold to enhance two-phase flow distribution. The porous structure of the packing elements creates capillary forces and surface tension effects that promote uniform distribution of liquid and vapor phases across all channels, solving the distribution problems inherent in plate type heat exchangers
2Reliability
If typical two-phase flow distributors are used in plate-type heat exchangers to improve flow distribution, then phase distribution is improved, but pressure drop increases by more than 18 psi
Solution Approach 1:
The invention changes the physical parameters of the distribution system by using packing material with specific properties (porosity, particle size, shape) that allow effective flow distribution at lower pressure drops. The packing is designed to create appropriate flow resistance through capillary effects rather than through high-velocity pressure drops, achieving distribution with pressure drop of no more than 5 psi
3Area of stationary object
If tubular heat exchangers are used to achieve desired heat transfer surface area, then heat transfer area is improved, but device complexity and cost increase due to wrapping and contortion in confined spaces
Solution Approach 1:
The invention transitions from one-dimensional tubular heat exchangers to a two-dimensional plate structure with distributed channels. This dimensional change allows the heat exchanger to achieve high surface area in a compact footprint without requiring complex three-dimensional tubing arrangements, thereby reducing device complexity and installation difficulty in confined spaces
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 solution achieves a pressure drop of no more than 5 psi and enhances the overall heat transfer coefficient by at least 2%, improving system efficiency and stability across various operating modes, including cool, standby, and defrost modes.
Implementation Method 1
A fluid entering the fluid inlet manifold may comprise at least two phases, which may be vapor and liquid
Implementation Method 2
a plurality of heat transfer channels configured to communicate with the fluid inlet manifold and the fluid outlet manifold
Implementation Method 3
The heat exchanger may be a plate-type heat exchanger, such as a counter-flow heat exchanger
Data Source
AI summary
Aspects of the invention are found in a heat exchanger. The heat exchanger includes a fluid inlet manifold, a fluid outlet manifold, a plurality of heat transfer channels configured to communicate with the fluid inlet manifold and the fluid outlet manifold, and packing located within the fluid inlet manifold. Further aspects of the invention are found in a refrigeration system. The refrigeration system includes a compressor and at least one heat exchanger coupled to the compressor. The at least one heat exchanger includes a header, packing located in the header, and a heat transfer channel. The heat transfer channel is configured to receive fluid passing through the header and the packing.