Microchannel Evaporator Manifold Insert for Uniform Refrigerant Distribution
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Solution Overview
Problem
Microchannel heat exchangers in refrigerant systems face refrigerant maldistribution issues due to phase separation of vapor and liquid phases during two-phase flow, which affects heat transfer and pressure drop characteristics, and existing distributor inserts are not effective in addressing this problem.
Innovation Solution
A microchannel heat exchanger design featuring a distributor insert with a plurality of orifices and dividing elements that create separation chambers, uniformly directing refrigerant into heat transfer tubes to prevent phase separation and ensure uniform distribution, applicable to both two-phase and single-phase refrigerant flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a conventional distributor insert is used in microchannel heat exchangers, then refrigerant delivery is provided, but refrigerant maldistribution occurs due to phase separation of vapor and liquid phases
Solution Approach 1:
The distributor insert is segmented into multiple distribution chambers separated by dividing elements. Each chamber receives refrigerant through dedicated orifices, creating discrete distribution zones that prevent vapor-liquid separation and ensure uniform refrigerant delivery to multiple heat transfer tubes simultaneously
Solution Approach 2:
Different regions of the distributor insert provide different functions: the outer periphery contains orifices for refrigerant injection, while the inner regions contain dividing elements that create separate distribution chambers. This local differentiation allows simultaneous achievement of refrigerant injection and phase mixture maintenance
2Productivity
If parallel flow heat exchangers are used with two-phase flow, then heat transfer performance is improved, but vapor phase separates from liquid phase causing maldistribution
Solution Approach 1:
The distributor insert performs preliminary action by distributing refrigerant into multiple small chambers before the refrigerant enters the parallel heat transfer tubes. This preliminary distribution prevents phase separation from occurring in the first place, maintaining uniform two-phase flow conditions throughout the heat exchanger
Solution Approach 2:
The dividing elements act as intermediaries that physically separate distribution chambers while allowing the refrigerant mixture to remain intact within each chamber. This intermediary structure prevents vapor-liquid separation without blocking the parallel flow paths needed for heat transfer
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 effectively prevents refrigerant maldistribution by maintaining the phases mixed within small separation chambers, ensuring uniform refrigerant distribution across heat exchange tubes, thereby optimizing heat transfer and pressure drop characteristics.
Implementation Method 1
the plurality of orifices are arranged to uniformly direct the refrigerant into the plurality of distribution chambers
Implementation Method 2
a plurality of heat transfer tubes; optimizing heat transfer and pressure drop characteristics
Data Source
Figure 1~3
Figure 4~5E
AI summary
An evaporator includes a manifold receiving a distributor insert. The distributor insert receives the flow of refrigerant to be delivered into the manifold, and has openings to communicate this refrigerant into a plurality of chambers which are defined between adjacent dividing elements of the distributor insert within the manifold. In this manner, these chambers are each associated with distinct heat transfer tubes and such that these chambers are isolated from each other.