Falling Film Evaporator Flow Segmentation Near Vapor Outlet
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Solution Overview
Problem
In falling film evaporators, refrigerant carry-over occurs frequently due to the rapid flow of refrigerant near the vapor outlet tube, leading to inefficient evaporation and potential compressor issues.
Innovation Solution
The implementation of an impeding member, such as a plate-shaped member with a surface perpendicular to the heat transfer tubes, is positioned between the liquid refrigerant sprinkling device and the cover to impede the flow of refrigerant, reducing the flow rate near the vapor outlet tube and preventing carry-over.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an upper cover is provided to impede liquid refrigerant from heading directly to the vapor outlet tube, then liquid refrigerant carry-over is reduced, but refrigerant flow rate increases below the cover and causes carry-over near the vapor outlet tube
Solution Approach 1:
The invention divides the space below the upper cover into multiple segments by providing partition plates that extend vertically. These partition plates create separate flow paths for the refrigerant, preventing rapid horizontal flow toward the vapor outlet tube while maintaining effective liquid refrigerant impeding. This segmentation resolves the contradiction by controlling flow velocity without compromising carry-over prevention.
Solution Approach 2:
The partition plates act as intermediary structures between the upper cover and the vapor outlet tube. They mediate the refrigerant flow by providing a controlled path that reduces flow velocity before the refrigerant reaches the vapor outlet tube, thereby preventing carry-over while maintaining system efficiency.
2Productivity
If refrigerant flows rapidly toward the vapor outlet tube, then evaporation efficiency is improved, but liquid refrigerant is carried along and flows out through the vapor outlet tube
Solution Approach 1:
The partition plates are designed with varying heights and positions to dynamically adapt to different refrigerant flow conditions. The structure creates a gradient flow pattern that maintains high velocity in evaporation zones while reducing velocity near the vapor outlet tube, resolving the contradiction between evaporation efficiency and carry-over prevention.
Solution Approach 2:
The invention introduces a vertical dimension to flow control by using partition plates of different heights. This creates multi-level flow paths that allow rapid evaporation in lower zones while controlling flow velocity in upper zones near the vapor outlet tube, thereby achieving both high evaporation efficiency and carry-over prevention.
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 configuration effectively suppresses the refrigerant flow rate near the vapor outlet tube, reducing carry-over and ensuring stable operation by maintaining a uniform refrigerant distribution and preventing liquid compression in the compressor.
Implementation Method 1
a heat transfer tube bundle (20), to the interior of which a heat medium is channeled, has a plurality of longitudinally extending heat transfer tubes (21)... the liquid refrigerant is evaporated by the heat transfer tube bundle
Implementation Method 2
the dropped liquid refrigerant is evaporated in the heat transfer tube bundle
Implementation Method 3
liquid refrigerant contained in gas/liquid two-phase refrigerant supplied into a tank (10) through a refrigerant inlet tube (17) is dropped onto a heat transfer tube bundle (20) by a liquid refrigerant sprinkling device (30) provided vertically between the heat transfer tube bundle (20) and a vapor outlet tube (18)
Data Source
Figure 1
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AI summary
The present invention provides a falling film evaporator in which the flow rate of refrigerant in the vicinity of a vapor outlet tube can be suppressed to be low. A falling film evaporator (1) in which liquid refrigerant, within gas/liquid two-phase refrigerant supplied into a tank (10), is dropped through a two-stage refrigerant tub (35) onto a heat transfer tube bundle (20). An upper cover (36) is provided above the two-stage refrigerant tub (35) inside the tank (10). A perpendicular plate (40) is provided between the two-stage refrigerant tub (35) and the upper cover (36), in a different position from a vapor outlet tube (18) with respect to the longitudinal direction of heat transfer tubes (21), and the perpendicular plate impedes the flow of refrigerant flowing between the two-stage refrigerant tub (35) and the upper cover (36) and flowing in the longitudinal direction of the heat transfer tubes (21).