Return Manifold Inserts for Uniform Multi-Pass Refrigerant Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional multi-pass heat exchangers face inefficiencies due to maldistribution of two-phase refrigerant mixtures, particularly in systems with many parallel refrigerant paths, leading to poor heat transfer efficiency and separation of liquid and vapor phases.
Innovation Solution
A multi-pass heat exchanger design featuring a return manifold with a partition and perforated insert that mixes and distributes fluid between collection and distribution chambers, ensuring even fluid communication and minimizing pressure drop, thereby addressing maldistribution issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple inlet header is used for heat exchangers with many parallel refrigerant paths, then device complexity is reduced, but refrigerant maldistribution occurs leading to poor heat transfer efficiency
Solution Approach 1:
The inlet header is segmented into multiple fluid channels separated by partitions, with each channel serving a specific group of refrigerant paths. This segmentation allows controlled distribution while maintaining manageable device complexity.
Solution Approach 2:
Different regions of the inlet header have different numbers of fluid channels (first region has first number, second region has second number), allowing local optimization of refrigerant distribution to match the specific requirements of different heat exchanger sections.
2Stability of the object's composition
If individual distribution devices are used for each parallel refrigerant path, then refrigerant distribution uniformity is improved, but device complexity increases making it impractical for heat exchangers with more than 20 paths
Solution Approach 1:
The system uses a small number of segmented fluid channels (rather than individual devices for each path) to distribute refrigerant to multiple parallel paths, achieving uniform distribution while keeping complexity low.
Solution Approach 2:
The inlet header structure serves multiple functions: it distributes refrigerant to many parallel paths, allows phase separation through gravity, and provides a compact design that works for heat exchangers with more than 20 refrigerant paths.
3Stability of the object's composition
If gravity acts on the two-phase mixture in the inlet header, then liquid and vapor separation occurs, but this separation causes maldistribution in the evaporator
Solution Approach 1:
The distributor tube performs preliminary mixing action at the inlet before the two-phase mixture enters the parallel refrigerant paths. This preliminary action counteracts the separating effect of gravity and ensures homogeneous distribution from the start.
Solution Approach 2:
The distributor tube acts as an intermediary element between the inlet header and the parallel refrigerant paths, mediating the two-phase flow to prevent maldistribution while allowing gravity to act on the mixture.
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 reduces maldistribution and enhances heat transfer efficiency by ensuring homogeneous mixing and distribution of the refrigerant mixture across multiple passes, improving overall heat exchanger performance.
Implementation Method 1
said front wall has a plurality of perforations placing said fluid channel in separate fluid communication with said collection chamber and said distribution chamber
Implementation Method 2
a return manifold having a partition, a front wall, and a rear wall, a collection chamber and a distribution chamber being on opposite sides of said partition and being in fluid communication
Implementation Method 3
as the refrigerant passes through the expansion valve, a pressure and temperature drop occurs
Data Source
Figure 1
Figure 2~3
AI summary
A multi-pass heat exchanger having a return manifold with a partition, a front wall, and a rear wall is provided. The partition separates the return manifold into a collection chamber and a distribution chamber. The front and rear walls define a fluid channel. The front wall has a plurality of perforations placing the fluid channel in separate fluid communication with the collection chamber and the distribution chamber.