Flash Tank Geometry for Stable Vapor-Liquid Separation

Solution Overview

Problem

Conventional flash tanks in vapor injection systems face inefficiencies due to turbulence, which hinders the separation of sub-cooled liquid and intermediate-pressure vapor, leading to increased energy consumption and reduced system performance.

Innovation Solution

The design of a flash tank with specific geometrical features such as a height-to-diameter ratio of four to six, tangentially positioned ports, and internal baffles to reduce turbulence and enhance separation of sub-cooled liquid and intermediate-pressure vapor, along with a vapor injection arrangement to control the liquid level and prevent mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional flash tanks are used with straight inlet ports, then the structure is simple, but turbulence occurs that hinders separation of sub-cooled liquid and intermediate-pressure vapor

Engineering Contradiction:

Improveseparation of sub-cooled liquid and intermediate-pressure vaporVSAvoidflash tank structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The flash tank is divided into distinct functional zones using internal baffles and a liquid level control assembly. The tank includes a vapor space and a liquid space separated by a baffle structure, with the liquid level control assembly further segmenting the liquid space. This segmentation creates controlled flow paths that reduce turbulence and enhance phase separation between sub-cooled liquid and intermediate-pressure vapor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Internal baffles and a liquid level control assembly are introduced as intermediary structures within the flash tank. These intermediaries act as flow directors and turbulence reducers, mediating the interaction between incoming liquid refrigerant and the existing vapor-liquid mixture. The baffles create gentle flow transitions that prevent violent mixing while maintaining effective separation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If liquid refrigerant flows directly into the flash tank, then the flow path is simple, but turbulence increases energy consumption and reduces system performance

Engineering Contradiction:

Improvesystem capacity and efficiencyVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The flash tank design incorporates preliminary flow conditioning through internal baffles and a liquid level control assembly before the refrigerant enters the main separation zone. The incoming liquid refrigerant is guided through a controlled path that reduces velocity and turbulence prior to mixing with the vapor-liquid mixture. This preliminary action prevents energy-wasting turbulence while maintaining separation efficiency.

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If the flash tank lacks internal flow control structures, then the device is simpler, but vapor and liquid mix more readily reducing separation efficiency

Engineering Contradiction:

Improvevapor-liquid separationVSAvoidinternal structures

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The flash tank is divided into distinct functional zones using internal baffles and a liquid level control assembly. The tank includes a vapor space and a liquid space separated by a baffle structure, with the liquid level control assembly further segmenting the liquid space. This segmentation creates controlled flow paths that reduce turbulence and enhance phase separation between sub-cooled liquid and intermediate-pressure vapor.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Internal baffles and a liquid level control assembly are introduced as intermediary structures within the flash tank. These intermediaries act as flow directors and turbulence reducers, mediating the interaction between incoming liquid refrigerant and the existing vapor-liquid mixture. The baffles create gentle flow transitions that prevent violent mixing while maintaining effective separation.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 improves the efficiency and capacity of vapor injection systems by reducing energy consumption and enhancing the performance of heat exchangers, allowing for more effective compression and heat transfer.

Implementation Method 1

Because the flash tank is held at a lower pressure relative to the inlet liquid refrigerant, some of the liquid refrigerant vaporizes, elevating the pressure of the vaporized refrigerant within the tank.

Methodology Applied

Scientific EffectVaporization: Evaporation

Implementation Method 2

The remaining liquid refrigerant in the flash tank loses heat and becomes sub-cooled for use by the evaporator.

Methodology Applied

Scientific EffectHeat transfer: Heat Exchanger

Data Source

PatentUS8505331B2Flash tank design and control for heat pumps

Publication Date: 2013.08.13 COPELAND LP

AI summary

A flash tank is provided and may include a shell having an inner volume. A first port may be in fluid communication with the inner volume and may be positioned relative to a surface of the inner volume such that fluid flows therebetween in a direction that is substantially tangent to the surface.