Compound Engine Assembly Fire Zone Isolation
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Solution Overview
Problem
Compound engine assemblies, particularly supercharged or turbocharged engines, are bulky and difficult to integrate into existing aircraft nacelles, posing challenges for adaptation in aircraft applications.
Innovation Solution
A compact compound engine assembly design featuring a gearbox module with a turbine section and compressor positioned on one side of the gearbox casing and a firewall extending radially to separate the hot and cold sections, allowing for modular components that can be easily maintained and reducing the fire hazard by isolating fuel systems and hot zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a compound engine assembly with supercharger or turbocharger is used, then power output and energy recovery are improved, but the assembly becomes bulky and difficult to integrate into aircraft nacelles
Solution Approach 1:
The patent combines the supercharger/compressor and turbocharger/turbine components into a single integrated compound engine assembly. The compressor and turbine are positioned on opposite sides of the gearbox module, sharing common structural elements and mounting arrangements, which reduces the overall volume while maintaining both power output and energy recovery functions
Solution Approach 2:
The design nests the gearbox module between the compressor and turbine sections, with the turbine shaft extending through the gearbox module casing to drive the compressor. This nested arrangement allows components to share space efficiently, reducing the total assembly volume while maintaining all necessary functional relationships
2Volume of moving object
If the turbine section and engine core are positioned close together for compactness, then integration into aircraft nacelles is improved, but fire hazard increases due to proximity of hot zones and fuel systems
Solution Approach 1:
The patent introduces a firewall as an intermediary barrier between the hot turbine section and the fuel system/compressor section. This firewall physically separates the zones while allowing the assembly to remain compact, thus maintaining small volume while reducing fire hazard by preventing direct exposure between hot components and fuel sources
Solution Approach 2:
The assembly is segmented into distinct zones separated by the firewall - a hot zone containing the turbine and exhaust, and a cold zone containing the compressor and fuel system. This segmentation allows compact positioning of components while maintaining safe separation between hazardous elements through the firewall barrier
3Ease of repair
If modular components are used for ease of maintenance, then maintenance accessibility is improved, but device complexity increases
Solution Approach 1:
The compound engine assembly is divided into modular sections - the compressor module, gearbox module, and turbine section - that can be independently accessed and maintained. The firewall and casing design provide natural separation points that facilitate modular maintenance while keeping the overall device architecture relatively simple and intuitive
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 design enables a compact, modular, and safer engine assembly that can be easily integrated into aircraft nacelles, improving maintenance and reducing the risk of fires while maintaining efficient energy recovery and performance.
Implementation Method 1
a turbine section having an inlet in fluid communication with an outlet of the engine core, the turbine section configured to compound power with the engine shaft
Implementation Method 2
a compressor having an outlet in fluid communication with an inlet of the engine core, the compressor including at least one compressor rotor
Data Source
AI summary
A compound engine assembly with an engine core including at least one internal combustion engine, a turbine section including a turbine shaft in driving engagement with the engine shaft, and a compressor, and a firewall. The compressor is located on one side of the firewall, and the turbine section and the engine core are located on the other side. The assembly may include a gearbox module with the turbine section and the engine core located on a same side of the gearbox module casing and the compressor located on the opposite side of the gearbox module casing, and with the firewall extending from the gearbox module casing. One or more rotatable accessory may be located on a same side of the firewall as the compressor. A method of reducing fire hazard in a compound engine assembly is also discussed.