Liquid Flow Redistribution Device for Two-Phase Fire Suppression
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Solution Overview
Problem
Inerting fire suppression systems face issues with non-homogenous distribution of water mist droplets in two-phase flow, leading to unequal distribution between downstream streams at pipe junctions, resulting in some spray nozzles receiving excessive water while others are under-supplied.
Innovation Solution
The implementation of liquid flow redistribution devices upstream of flow splitting tees in the inert gas distribution network, such as swirler devices, annular ring members, and venturi scoop devices, to ensure a uniform distribution of water droplets within the two-phase flow, preventing unequal distribution between outgoing flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water is injected into high velocity inert gas stream in long horizontally extending pipes, then the two-phase mixture is transported to discharge nozzles, but water mist droplets concentrate in the lower half of the flow causing non-homogenous distribution
Solution Approach 1:
A flow redistributing device is introduced as an intermediary component in the horizontal stretch of pipe upstream of the tee junction. This device mediates the two-phase flow by redistributing water droplets that have settled in the lower half of the pipe, injecting them back into the upper half to achieve uniform distribution before the flow splits at the junction.
Solution Approach 2:
The flow redistributing device changes the spatial distribution parameter of water droplets within the two-phase flow. By actively redistributing droplets from the lower half to the upper half of the pipe cross-section, it transforms the non-homogenous concentration profile into a uniform distribution, ensuring proportional water division at downstream junctions.
2Manufacturing precision
If water droplets are non-uniformly distributed in the flow entering the junction, then the two-phase flow is divided at the junction, but water does not distribute proportionally between outlet pipes causing some nozzles to be over-supplied and others under-supplied
Solution Approach 1:
The flow redistributing device performs preliminary action by uniformizing water droplet distribution in the horizontal pipe stretch upstream of the tee junction. This preliminary redistribution ensures that when the two-phase flow reaches the junction and divides into outlet pipes, the water is already uniformly distributed and will therefore divide proportionally with the gas flow, maintaining consistent mass flow ratios at all discharge nozzles.
3Temperature
If water mist droplets concentrate in the lower half of two-phase flow, then gravitational settling occurs, but proportional distribution at junctions is compromised
Solution Approach 1:
The flow redistributing device applies preliminary anti-action to counteract gravitational settling of water droplets in horizontal pipe stretches. By detecting and redistributing droplets that have settled in the lower half of the pipe, it pre-compensates for the gravitational effect, ensuring uniform distribution before the flow reaches the junction where proportional division is critical.
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 solution effectively reduces the potential for unequal liquid phase distribution at pipe intersections, ensuring a more uniform distribution of water mist droplets throughout the system, thereby maintaining a consistent mass flow ratio of liquid to gas and preventing under or over-supply of water at spray nozzles.
Implementation Method 1
a two-phase mixture of water mist droplets entrained in and carried by the inert gas stream is distributed via the network of distribution pipes
Implementation Method 2
Upon interaction of the high velocity stream of inert gas with the water jet, the water droplets in the water jet are atomized into a mist of very small or minute droplets
Implementation Method 3
venturi scoop devices, to ensure a uniform distribution of water droplets within the two-phase flow
Data Source
Figure 1
Figure 2A~4
Figure 5~7
AI summary
A two-phase liquid/inert gas flow inerting fire suppression system is provided having improved liquid fire suppressant distribution within the inert gas flow. The system includes a flow distribution network having a first pipe interconnected with a second pipe at a flow splitting tee. A liquid flow redistribution device is disposed in the first pipe upstream with respect to fluid flow of the flow splitting tee.