L-Shaped Fuel Injector Pivoting Mount for Axial Size Reduction
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Solution Overview
Problem
The existing fuel injector mounting and dismantling process in turbomachine combustion chambers is cumbersome, leading to increased engine length and weight due to the required translation distance, which is penalizing in aviation applications, especially when an axial-centrifugal compressor diffuser impedes upstream movement.
Innovation Solution
The introduction of a sectorized annular spacer between the injector arm collar and the casing allows the injector to pivot, reducing the axial translation distance needed for dismantling and enabling a shorter engine design by providing a degree of freedom in rotation, thus reducing the axial size and weight of the turbomachine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the injector is moved in translation parallel to the axis of its head for dismantling, then the injector can be disengaged from the mixer, but the axial size and weight of the engine increase
Solution Approach 1:
The patent changes the dismantling motion from purely translational (one dimension) to a rotational pivot motion (another dimension). The injector pivots about a transverse axis passing through the collar, allowing disengagement from the mixer without requiring large axial translation. This dimensional change in motion resolves the contradiction by enabling easy dismantling while minimizing axial size increase.
2Ease of operation
If the injector is moved in translation parallel to the axis of its head for dismantling, then the injector can be disengaged from the mixer, but the weight of the engine increases
Solution Approach 1:
By introducing rotational pivot motion as the dismantling mechanism, the patent reduces the axial translation distance required, which directly reduces the axial size of the engine. Since engine weight is proportional to its size, this dimensional change in motion simultaneously reduces both the axial dimension and the overall weight, resolving the contradiction between ease of operation and weight.
3Ease of operation
If clearance is left between the diffuser and the injector for complete removal, then the injector can be removed completely, but the axial size of the engine increases
Solution Approach 1:
The patent eliminates the need for large axial clearance between the diffuser and injector by changing the removal motion from translational to rotational. The injector pivots about a transverse axis, allowing the head to disengage from the mixer while the collar remains positioned such that minimal clearance (about 7.4 mm) is sufficient. This resolves the contradiction by enabling complete removal without requiring excessive axial space.
Solution Approach 2:
The patent introduces a transverse axis as an intermediary pivot point through the collar, around which the injector rotates during dismantling. This intermediary axis enables the injector to swing out of the way of the diffuser, allowing complete removal with minimal axial clearance. The pivot axis acts as a mediator that decouples the removal motion from the axial direction, resolving the space constraint contradiction.
4Stability of the object's composition
If the collar bears against the boss of the casing, then the injector is securely mounted, but the axial translation distance for dismantling increases
Solution Approach 1:
The patent maintains the stable mounting by keeping the collar-boss contact for securing the injector, but introduces a rotational pivot motion about a transverse axis through the collar for dismantling. This allows the injector to pivot out of engagement with the mixer while the collar remains positioned against the boss, maintaining stability. The rotational dimension enables dismantling with minimal axial translation, resolving the contradiction between mounting stability and translation distance.
Data Source
AI summary
A turbomachine combustion chamber including a substantially L-shaped fuel injector and a device for mounting and fastening the injector in an orifice of the casing of the chamber, is disclosed. The device includes an outer collar carried by the injector and a removable annular spacer surrounding the injector and designed to be interposed between the collar of the injector and the casing.