Straddle-Mounted Low-Pressure Compressor Support for Spool Alignment
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Solution Overview
Problem
Existing gas turbine engines with gear reduction systems face challenges in efficiently supporting the low spool and high spool components, particularly in terms of structural support and alignment, which can affect performance and efficiency.
Innovation Solution
The low spool is supported by a combination of bearings located axially forward and aft of the low pressure compressor, with the forward support provided by the front center body and aft support by the intermediate case, while the high spool is supported by the mid-turbine frame and diffuser case, ensuring stable rotation and alignment through a geared architecture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the low spool is supported by bearings located axially forward and aft of the low pressure compressor, then the structural integrity and alignment of the spool components is improved, but the device complexity increases due to the combination of multiple support locations and bearing systems
Solution Approach 1:
The support system is segmented into multiple independent bearing locations: forward support bearings (232, 234) mounted on the front center body (220) and aft support bearings (242, 244) mounted on the intermediate case (224). This segmentation allows each bearing to independently support specific portions of the low spool (204), improving stability and alignment while distributing the structural load across multiple discrete support points rather than requiring a single complex support structure
Solution Approach 2:
The front center body (220) and intermediate case (224) serve as intermediary structures that mount the bearing systems. These intermediaries provide stable reference frames for mounting the forward and aft support bearings, enabling precise alignment of the low spool components without directly coupling the spool to the main engine structure, thus improving structural integrity while maintaining manageable device complexity
2Stability of the object's composition
If the high spool is supported by the mid-turbine frame and diffuser case, then the stability and alignment of the high spool is improved, but the device complexity increases due to the distributed support structure
Solution Approach 1:
The high spool support system is segmented into forward support bearings (212, 214) mounted on the mid-turbine frame (228) and aft support bearings (222, 224) mounted on the diffuser case (216). This segmentation provides distributed support at multiple axial locations, improving the stability and alignment of the high spool (208) by preventing deflection and maintaining precise rotational alignment, while the modular bearing pairs at each location keep the implementation complexity manageable
Solution Approach 2:
The mid-turbine frame (228) and diffuser case (216) act as intermediary structures that provide stable mounting surfaces for the high spool support bearings. These intermediaries distribute the support loads and provide precise alignment references, enabling the high spool to maintain stable rotation without requiring direct attachment to the main engine structure, thus improving alignment while managing device complexity
3Productivity
If a geared architecture is used to drive the fan, then the efficiency and performance of the engine is improved, but the device complexity increases due to the additional gear reduction system
Solution Approach 1:
The low spool support bearings (both forward bearings 232, 234 on the front center body and aft bearings 242, 244 on the intermediate case) serve dual functions: they support the low spool structure and provide mounting points for the geared architecture components. This multi-functionality allows the engine to achieve improved efficiency through gear-driven fan operation while avoiding additional dedicated support structures, thereby managing device complexity
Solution Approach 2:
The support structure for the low spool is merged with the mounting structure for the gear reduction system. The front center body and intermediate case serve both as structural supports for the low spool bearings and as mounting frameworks for the geared architecture components, combining multiple functions into unified structures that improve efficiency without proportionally increasing device complexity
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 configuration enhances the structural integrity and efficiency of the spool components, improving the overall performance and reducing mechanical stress, thereby optimizing the operation of the gas turbine engine.
Implementation Method 1
The low spool is supported by a combination of bearings located axially forward and aft of the low pressure compressor
Implementation Method 2
ensuring stable rotation and alignment through a geared architecture
Data Source
Figure 1
Figure 2
AI summary
A gas turbine engine (20) includes a fan section (22) including a fan (42) with fan blades (43). The fan section (22) drives air along a bypass flow path (B) in a bypass duct (13). A gear reduction (48) is in driving engagement with the fan (42). The gear reduction (48) is a planetary gear system (48). A low spool (30) includes a low pressure turbine (46) that drives a low pressure compressor (44) and drives the gear reduction (48) to drive the fan (42) at a speed slower than the low pressure turbine (46). A high spool (32) includes a high pressure turbine (54) that drives a high pressure compressor (52). A first low spool support bearing (38A) is located axially between the low pressure compressor (44) and the gear reduction (48). A second low spool support bearing (38B) is located axially between the low pressure compressor (44) and the high pressure compressor (52).