Evaporator Header Baffle for Uniform Refrigerant Distribution
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Solution Overview
Problem
Existing evaporators in car air conditioners face issues with uniform refrigerant flow distribution, leading to non-uniform discharged air temperatures due to the separation of gas and liquid phases within the evaporator, causing uneven refrigerant flow through heat exchange tubes.
Innovation Solution
The implementation of a horizontal baffle in the refrigerant inflow section of the evaporator, which divides the space into upper and lower sections, prevents the flow of refrigerant towards the upper space and ensures that the gas and liquid phases are mixed adequately, resulting in uniform refrigerant distribution across all heat exchange tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If refrigerant flows through upward and downward tube groups without phase separation control, then the evaporator structure is simple, but the discharged air temperature becomes non-uniform due to gas-liquid phase separation
Solution Approach 1:
The header portion is segmented into a refrigerant inflow section and a refrigerant outflow section using a partition wall. This segmentation prevents direct communication between sections, forcing refrigerant to flow through the partition wall and promoting phase mixing. The partition wall divides the header into distinct functional zones that control refrigerant flow paths separately.
Solution Approach 2:
The partition wall acts as an intermediary structure between the refrigerant inflow section and outflow section. It prevents direct flow communication while allowing controlled refrigerant passage, serving as a mediator that promotes phase mixing before refrigerant enters the downward flow tube group.
2Productivity
If refrigerant flows directly from inflow to outflow section, then the flow path is short and simple, but gas and liquid phases separate causing non-uniform refrigerant distribution
Solution Approach 1:
The partition wall is positioned to force refrigerant to undergo preliminary mixing action before entering the outflow section. Refrigerant must flow along the partition wall and through the inflow section, undergoing preliminary phase mixing that ensures uniform distribution before entering downward flow tubes.
Solution Approach 2:
The partition wall creates local flow characteristics within the header portion. Different regions of the header have different flow patterns - the inflow section promotes mixing while the outflow section distributes refrigerant uniformly to multiple tube groups, achieving local optimization of flow quality.
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 solution ensures that the refrigerant enters the heat exchange tubes with a consistent dryness, effectively maintaining uniform diverging flows and improving the uniformity of discharged air temperatures across the evaporator.
Implementation Method 1
a horizontal baffle is provided in the refrigerant inflow section which communicates with upper end portions of the heat exchange tubes of the upward flow tube group such that the baffle is located at a central position in the vertical direction... the baffle dividing a portion of the interior of the refrigerant inflow section into upper and lower spaces and preventing flow of refrigerant toward the upper space
Implementation Method 2
An evaporator comprises a plurality of heat exchange tubes extending in a vertical direction, and upper and lower header portions to which upper and lower end portions of the heat exchange tubes are connected
Data Source
AI summary
A leeward upper header portion of an evaporator includes first through third sections which communicate with upper ends of heat exchange tubes of first through third tube groups of a leeward tube row. The second tube group, which is an upward flow tube group, and the third tube group, which is a downward flow tube group, form a tube group set. A baffle plate is provided in the second section to be located on the side toward the third section. The baffle plate divides a portion of the interior of the second section into upper and lower spaces and prevents flow of refrigerant toward the upper space. A flow prevention member is provided below the baffle plate so as to prevent flow of refrigerant from the second section into the third section. These two sections communicate with each other in a region above the baffle plate.