Multi-Stage Refrigerant Distributor for Gas-Liquid Separation
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Solution Overview
Problem
Conventional vapor compression refrigeration systems face issues with liquid carryover and reduced heat transfer performance due to inadequate gas-liquid separation in the refrigerant distributor, particularly with Low Pressure Refrigerant (LPR) systems, leading to inefficient distribution of refrigerant to the tube bundle.
Innovation Solution
A heat exchanger with a refrigerant distributor that includes multiple stages of gas-liquid separation and distribution, featuring a longitudinal design with specific openings and tray configurations to separate and distribute liquid refrigerant effectively, reducing gas bubbles and liquid droplets, and ensuring even distribution across the tube bundle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional refrigerant distributor design is used, then device complexity is low, but gas-liquid separation is insufficient leading to liquid carryover and reduced heat transfer performance
Solution Approach 1:
The distributor is divided into multiple sections (first section with first tray, second section with second tray) that perform gas-liquid separation in stages. Each section has specific openings (first openings, second openings, third openings) that create multiple separation interfaces, progressively removing liquid from vapor to achieve thorough separation before refrigerant enters the evaporator tubes.
Solution Approach 2:
The distributor utilizes vertical dimension by stacking trays at different heights (first tray, second tray) to create multiple separation levels. This three-dimensional arrangement allows gravity to act on liquid refrigerant at different stages, enabling effective gas-liquid separation without requiring a larger horizontal footprint or excessive complexity.
2Productivity
If vapor speed is high, then refrigerant flow rate increases, but vapor entrains liquid and causes non-uniform distribution
Solution Approach 1:
The distributor performs gas-liquid separation before the refrigerant enters the evaporator tubes. The first and second trays with their respective openings create preliminary separation stages that remove liquid from high-speed vapor flow, preventing liquid entrainment and ensuring uniform liquid distribution to all evaporator tubes even at high vapor velocities.
Solution Approach 2:
The trays and their openings act as intermediary structures between the high-speed vapor-liquid mixture from the inlet and the evaporator tubes. These intermediaries provide multiple separation interfaces that gradually remove liquid from the vapor stream, mediating the transition from high-speed two-phase flow to controlled liquid distribution.
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 enhances the separation of liquid and gas refrigerants, reducing liquid carryover and improving heat transfer performance by ensuring only liquid refrigerant is distributed to the tube bundle, thereby increasing the efficiency of the evaporator and compressor.
Implementation Method 1
it is desirable for as much as possible of the liquid refrigerant be separated from the gas refrigerant in the distributor
Implementation Method 2
The second portion is connected to the first portion to receive refrigerant from the at least one first refrigerant liquid distribution opening. The second portion has at least one second refrigerant liquid distribution opening
Data Source
AI summary
A heat exchanger includes a shell, a refrigerant distributor disposed in the shell, and a heat transferring unit disposed in the shell. The shell has a refrigerant inlet through which at least liquid refrigerant flows and a shell refrigerant vapor outlet. The refrigerant distributor includes a first portion and a second portion. The first portion is connected to the refrigerant inlet to receive refrigerant from the inlet. The first portion has at least one first refrigerant liquid distribution opening and a first refrigerant vapor distribution outlet opening. The second portion is connected to the first portion to receive refrigerant from the first refrigerant liquid distribution opening. The second portion has at least one second refrigerant liquid distribution opening and at least one second refrigerant vapor distribution outlet opening. The heat transferring unit is disposed below the refrigerant distributor to receive liquid refrigerant discharged from the second portion of refrigerant distributor.