Modulated Fire Extinguishing Vent for Gas Turbine Engine
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Solution Overview
Problem
Current fire suppression systems in gas turbine engines require large volumes of fire suppressant to effectively reduce oxygen concentration and extinguish fires, as the existing vents allow excessive airflow, leading to inefficient use of suppressant and increased weight and volume of suppressant sources.
Innovation Solution
A modulated fire extinguishing vent system with flaps that can be actuated to restrict airflow, allowing the fire suppressant to maintain a higher concentration within the engine core cavity by mechanically disconnecting or powering the actuator to pivot or extend flaps, thereby reducing the volume of suppressant needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the vent is left unrestricted to maintain normal airflow, then the fire suppressant can be quickly dispersed throughout the cavity, but the oxygen concentration cannot be sufficiently reduced and the suppressant volume required increases
Solution Approach 1:
The vent flap is designed to be dynamically adjustable between unrestricted and restricted positions. During normal operation, the flap remains unrestricted to maintain airflow. Upon fire detection, the actuator pivots the flap to a restricted position that reduces airflow through the vent, allowing fire suppressant to accumulate and effectively reduce oxygen concentration in the cavity.
Solution Approach 2:
The system changes the flow parameter of the vent by pivoting the flap from an unrestricted to a restricted position. This parameter change (from open to partially closed) controls the rate at which air enters and exits the cavity, enabling the fire suppressant to maintain sufficient concentration for effective fire suppression while still allowing some airflow for heat dissipation.
2Weight of stationary object
If the vent is restricted to maintain suppressant concentration, then the volume of suppressant needed is reduced, but the airflow required for cooling and oxygen supply is limited
Solution Approach 1:
The vent flap is restricted to a partial extent rather than completely closed. This partial restriction (approximately 45 degrees from horizontal) is sufficient to reduce airflow to levels that allow effective suppressant concentration while still permitting adequate cooling airflow and oxygen supply to the engine core, thus achieving fire suppression with reduced suppressant volume without completely stifling necessary airflow.
3Reliability
If a large volume of suppressant is used to ensure fire extinguishment, then fire suppression reliability is improved, but the weight and volume of suppressant sources increases
Solution Approach 1:
The system performs preliminary action by restricting the vent airflow before or during suppressant discharge. By pre-restricting the vent (or simultaneously restricting while discharging), the system creates favorable conditions for suppressant accumulation, ensuring that the discharged suppressant volume is used efficiently to achieve reliable fire extinguishment with minimal suppressant quantity.
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 restricted vent configuration allows for a lower volume of fire suppressant to achieve the necessary oxygen reduction, reducing the weight and volume of suppressant sources, while ensuring effective fire extinguishment.
Implementation Method 1
The actuator may be actuated by a phase change material disposed in a chamber and having a liquid state below a predetermined actuation temperature and a gaseous state above the predetermined actuation temperature
Implementation Method 2
The thermal fuse may include at least a portion of piston rod or a cylinder wall of the actuator being made of a fuse material which has a melting point substantially above the predetermined actuation temperature
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A gas turbine engine (20) includes an engine core (80) having a compressor (24), a combustor (26) fluidly connected to the compressor (24), and a turbine (28) fluidly connected to the combustor (26). A core nacelle (82) is disposed radially outward of the engine core (80). A cavity (84) is disposed between an inner surface of the core nacelle (82) and an outer surface of the engine core (80). The cavity (84) includes a vent (88) disposed at an aft end. The vent (88) includes at least one flap configured to be maintained in an unrestricted positon and in a restricted position. An actuator (110) is configured to control the position of the at least one flap (130).