Heat Exchanger Distributor Layout for Stable Two-Phase Refrigerant Split
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Solution Overview
Problem
Existing air-conditioning apparatus heat exchangers with distributors that split two-phase gas-liquid refrigerant into multiple heat transfer tubes face challenges in maintaining heat exchange performance across varying operational capacities due to reduced upward momentum of refrigerant, leading to inadequate liquid refrigerant distribution and increased pressure loss, which affects energy efficiency and manufacturing costs.
Innovation Solution
A heat exchanger design with a distributor that includes a body part and flow-splitting parts, where the second inlets of at least two flow-splitting parts communicate above the first inlet, ensuring consistent refrigerant distribution to all heat transfer tubes, preventing liquid refrigerant deprivation during low-capacity operations and minimizing component count and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the effective cross-sectional area of the passage within the body part is reduced to increase upward momentum of two-phase gas-liquid refrigerant, then liquid refrigerant can reach higher positioned flow-splitting parts during low-capacity operation, but pressure loss within the distributor increases and heat exchange performance degrades during high-capacity operation
Solution Approach 1:
The distributor is divided into a body part and multiple flow-splitting parts, with the passage in the body part segmented into multiple regions. Each region supplies refrigerant to different flow-splitting parts at different heights, allowing optimized flow distribution without reducing overall passage area
Solution Approach 2:
Different regions of the passage are designed with different characteristics to suit local requirements. The passage cross-sectional area varies along its length, and flow-splitting parts are positioned at different heights with different inlet areas, creating local optimizations that collectively solve the global contradiction between momentum and pressure loss
2Reliability
If the effective cross-sectional area of the passage within the body part is reduced to increase upward momentum, then heat exchange performance is maintained during low-capacity operation, but manufacturing cost increases due to more complex distributor structure
Solution Approach 1:
The flow-splitting parts are integrated with the heat transfer tubes, combining the distributor function and heat transfer function into a unified structure. This reduces the number of separate components and simplifies manufacturing while maintaining the complex flow distribution pattern needed for performance
3Ease of manufacture
If the distributor structure is simplified to reduce manufacturing cost, then ease of manufacture improves, but liquid refrigerant may be deprived from higher positioned heat transfer tubes during low-capacity operation
Solution Approach 1:
The distributor design accounts for dynamic operating conditions. The varying passage cross-sectional area and differently sized flow-splitting part inlets create a system that adapts to different refrigerant flow rates, maintaining reliable distribution across both low-capacity and high-capacity operations without requiring complex active control mechanisms
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 maintains heat exchange performance across a wide range of operational capacities without reducing the effective cross-sectional area, ensuring efficient refrigerant distribution and reduced manufacturing costs by preventing liquid refrigerant deprivation and minimizing pressure loss.
Implementation Method 1
Two-phase gas-liquid refrigerant flowing upward in the passage within the body part is discharged sequentially from lower positioned flow-splitting parts. This results in reduced upward momentum of the two-phase gas-liquid refrigerant near higher positioned flow-splitting parts.
Implementation Method 2
under conditions of low refrigerant circulation rate within the refrigeration cycle circuit such as during low-capacity operation of the air-conditioning apparatus, if the upward momentum of two-phase gas-liquid refrigerant becomes less than or equal to a certain value, gravity hinders the upward flow of liquid refrigerant
Implementation Method 3
a heat exchanger that functions as an evaporator. Two-phase gas-liquid refrigerant, which is a mixture of gas refrigerant and liquid refrigerant, flows into the evaporator
Data Source
AI summary
A heat exchanger includes plural heat transfer tubes disposed with a specified spacing from each other in the up and down direction, and a distributor configured to distribute refrigerant to the heat transfer tubes. The distributor includes a body part, and plural flow-splitting parts, the body part including a first passage in which refrigerant flows upward, the flow-splitting parts communicating with the first passage and with one of the heat transfer tubes. The flow-splitting parts include one or more first flow-splitting parts each communicating with a first heat transfer tube, which is a higher positioned heat transfer tube. The flow-splitting parts include one or more second heat transfer tubes each communicating with a second heat transfer tube positioned below the first heat transfer tube. The refrigerant inlet of the first flow-splitting part communicates with the first passage at a location below the refrigerant inlet of the second flow-splitting part.