Micro-Channel Evaporator Layout for Refrigerant Phase Separation
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Solution Overview
Problem
Existing evaporators in refrigerant circuits, such as those in vehicle air conditioning systems, face challenges with complex process technology and structurally complicated separator geometries, particularly in achieving efficient phase separation using centrifugal force.
Innovation Solution
The evaporator design incorporates micro-channels divided into vapour and liquid phase micro-channels, with specific orifice openings and a distributor tube configuration that allows for simple and efficient phase separation, reducing pressure loss and preventing vapour return flow through a pocket-shaped phase separation space and vapour return flow preventers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centrifugal force is used for phase separation in the separator, then phase separation can be achieved, but the process technology becomes complicated and the separator geometry becomes structurally complex
Solution Approach 1:
The micro-channels are segmented into two distinct types: vapour phase micro-channels positioned above the liquid phase level and liquid phase micro-channels dipped into the liquid phase. This segmentation eliminates the need for complex centrifugal separation mechanisms while achieving effective phase separation through simple gravitational settling and channel positioning.
Solution Approach 2:
The invention extracts the complex centrifugal separation mechanism from the separator and replaces it with a simplified structure that uses only gravitational separation. The separator geometry is taken out and replaced by strategic positioning of micro-channel orifices at different heights relative to the liquid phase level.
2Device complexity
If all micro-channels are positioned at the same level, then the structure is simple, but vapour return flow cannot be prevented and phase separation is inefficient
Solution Approach 1:
Different regions of the micro-channel array are assigned different vertical positions based on their function. Vapour phase micro-channels are locally positioned above the liquid phase level to allow vapour passage, while liquid phase micro-channels are locally dipped into the liquid phase to prevent vapour return. This local differentiation achieves both simplicity and effectiveness.
3Ease of operation
If liquid phase micro-channel orifices are positioned far from the chamber bottom, then liquid phase flow is smooth, but vapour return flow cannot be prevented
Solution Approach 1:
The liquid phase micro-channel orifices are preliminarily positioned to dip into the liquid phase before the vapour-liquid separation point. This preliminary positioning ensures that liquid phase flows smoothly into the channels while vapour is blocked from entering, preventing vapour return flow before it can occur.
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
This design enhances phase separation efficiency, reduces pressure loss, and prevents vapour return flow, resulting in a more straightforward and effective evaporator operation with improved performance.
Implementation Method 1
the liquid phase collects on the chamber bottom of the inlet chamber with a filling level
Implementation Method 2
The refrigerant liquid phase in the evaporator is therefore evaporated into the vapour phase with absorption of thermal energy from the air flow
Implementation Method 3
the air flow is cooled at the same time
Data Source
AI summary
An evaporator in a refrigerant circuit, having a bottom-side inlet chamber which is connected in flow terms to an evaporator outlet side via evaporator tubes, a separator being integrated into the evaporator inlet chamber, in which separator a refrigerant which is expanded in an expansion member is divided as a two-phase liquid/vapour mixture into a vapour phase and into a liquid phase which is separate therefrom, the vapour phase being conducted via a bypass line to the evaporator outlet side, and the liquid phase being conducted counter to the direction of gravity into the evaporator tubes, to be precise at least one evaporator tube being a flat tube with a plurality of micro-channels, through which the refrigerant is guided, wherein, as a first flat tube, the evaporator flat tube is a constituent part of a first evaporator tube set which guides the refrigerant from the bottom-side inlet chamber counter to the direction of gravity into an upper-side deflecting chamber, and wherein the refrigerant is guided back from the upper-side deflecting chamber via at least one second flat tube.