Titanium Compressor Casing with Refractory Shield for Fire Resistance
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Solution Overview
Problem
High-pressure compressor casings in turbomachines, such as aircraft turbojets, face the risk of titanium fire due to friction between moving and fixed parts, leading to overheating and combustion, with existing solutions being heavy, bulky, and not compatible with the lifespan of turbomachines.
Innovation Solution
A titanium or titanium alloy casing with refractory steel or alloy shields that are secured to the internal wall, forming a mixed structure that maintains the mechanical strength and low density of titanium while providing thermal protection against titanium fires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If titanium or titanium alloy is used for the compressor casing to maintain mechanical strength and low density, then the mechanical resistance and low density are improved, but the risk of titanium fire increases due to friction and overheating
Solution Approach 1:
A refractory alloy liner is introduced as an intermediary layer between the titanium casing and the combustion environment. This liner acts as a thermal barrier and fire-resistant shield, preventing direct contact between burning titanium particles and the titanium casing structure, thereby eliminating the fire risk while preserving the titanium's mechanical advantages
Solution Approach 2:
The compressor casing is constructed as a composite structure combining titanium outer casing with a refractory alloy inner liner. This composite design integrates the low density and high mechanical strength of titanium with the fire resistance and high-temperature stability of refractory alloys, achieving both safety and performance requirements
2Object-affected harmful factors
If steel or nickel-based alloys are used to replace titanium to prevent titanium fire, then the fire resistance is improved, but the weight and bulk increase significantly
Solution Approach 1:
The casing is segmented into two functional zones: an outer titanium casing that provides structural strength and low weight, and an inner refractory alloy liner that provides fire resistance. This segmentation allows each material to be used where it is most effective, avoiding the need to make the entire casing from heavy fire-resistant materials
Solution Approach 2:
Fire resistance is applied locally only where needed - in the form of a liner in the zones most susceptible to titanium fire (such as near blade tips and friction-prone areas) - rather than making the entire casing from heavy fire-resistant materials, thus optimizing the weight-protection balance
3Object-affected harmful factors
If thermal protection layers or liners are installed on the crankcase to protect from titanium fire, then the fire protection is improved, but the device complexity and bulk increase
Solution Approach 1:
The fire protection function is merged with the structural casing itself by forming the refractory alloy liner as an integral part of the compressor casing structure. This integration eliminates the need for separate, bulky external protection systems while maintaining effective fire resistance
Solution Approach 2:
The refractory alloy liner serves multiple functions simultaneously: it provides fire resistance, acts as a thermal barrier, maintains structural integrity at high temperatures, and forms part of the compressor casing structure. This multi-functionality reduces the need for additional separate protection systems
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 effectively protects against titanium fires while retaining the advantages of titanium, including high mechanical strength and low density, and reduces the mass of the compressor casing compared to all-steel solutions, ensuring the compressor's longevity and safety.
Implementation Method 1
at least one shield-forming element made of refractory alloy(s) and incombustible to the titanium in combustion
Data Source
Figure 1
Figure 2A~2B
AI summary
The invention relates to a novel type of casing (10) for a compressor that is resistant to titanium fire (burning titanium). The invention comprises making a mixed casing (10) in which the fixed blade carrying structure (2) comprises a unitary part made of titanium or a titanium alloy and at least one shield-forming member (12, 120, 121, 122) made of one or more refractory alloys and which is incombustible to titanium fire, the shield(s) being connected to the unitary part by a connection means (13, 130) arranged with the shield(s) so as to form together the inner wall defining the outer contour (40) of the compressor jet (4).