Nacelle Hatch Contour for Turbojet Engine Access
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Solution Overview
Problem
The existing nacelle designs for turbojet engines with thrust reverser systems require time-consuming and space-intensive processes for maintenance, as they demand the removal and storage of bulky front cowls, which complicates handling and transportation.
Innovation Solution
The nacelle design features hatch openings with contours formed by edges of two front cowls, allowing for independent removal and installation of cowls without interfering with handling interfaces, enabling the turbojet engine to be lifted and transported with cowls still in place, and facilitating easy access for maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If front cowls are removed to access fastening points for handling and transportation, then access to fastening points is improved, but time consumption and space requirements for storage increase
Solution Approach 1:
The opening contour is segmented across two adjacent cowls rather than being contained within a single cowl. This segmentation allows the handling interface to be accessed through a distributed opening structure, enabling cowl removal operations to be performed more efficiently without requiring complete disassembly of all cowls, thus reducing time loss while maintaining access to fastening points
Solution Approach 2:
The opening contour utilizes the boundary between two cowls in a radial arrangement, transitioning from a single-cowl constrained opening to a multi-dimensional opening spanning cowl interfaces. This dimensional approach allows the opening to leverage the spatial relationship between adjacent cowls, providing access to fastening points without requiring removal of all cowls and reducing storage space requirements
2Ease of operation
If front cowls are removed to access fastening points, then handling interface access is improved, but space for storage and transportation complexity increases
Solution Approach 1:
By segmenting the opening contour across two adjacent cowls, the design enables selective access to fastening points without requiring removal of all front cowls. This reduces the quantity of dismantled components that need storage space, directly addressing the storage area constraint while maintaining operational access to handling interfaces
Solution Approach 2:
The opening contour is pre-configured at the junction of two cowls, allowing maintenance personnel to access fastening points through this pre-positioned opening without needing to completely disassemble the cowl assembly first. This preliminary arrangement of the opening structure eliminates the need for extensive preliminary cowl removal and storage operations
3Ease of operation
If a wide area of front cowls is removed to access fastening points, then access to fastening points is improved, but structural integrity and aerodynamic efficiency are compromised
Solution Approach 1:
The opening contour is segmented to span the junction of two adjacent cowls rather than removing a continuous wide area from a single cowl. This segmented approach maintains structural integrity by preserving the majority of the cowl structure while providing sufficient access to fastening points, avoiding the need to compromise the overall structural strength of the nacelle
Solution Approach 2:
The opening contour is strategically positioned at the junction of two cowls where the structural requirements are slightly different from the main cowl bodies. This local positioning allows the opening to be accommodated with minimal impact on overall structural integrity, as the junction area can better accommodate the opening while maintaining the strength of the individual cowl sections
Data Source
AI summary
A nacelle for a bypass turbojet engine includes a cascade thrust reverser provided with reversal cascades arranged around an annular stream of fresh air, beneath front cowls. The cascades move backward with movable rear cowls, opening side passages in the annular stream, which receive the cascades for directing the fresh air flow forward, the bypass turbojet engine. The bypass turbojet engine includes fixing points, and the nacelle includes outer hatches closing openings of the front cowls, which are arranged radially outside the fixing points for access thereto, each hatch opening including a contour with edges of two front cowls.