Variable Stator Vane Heating Element Routing Through Pivot Bore
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Solution Overview
Problem
Existing turbomachines face issues with mechanical stress and reliability of heating elements for variable-pitch stator blades due to excessive power cable length and interaction with the pitch change system, leading to durability problems and complex assembly, along with limited heat transfer and power density.
Innovation Solution
A turbomachine assembly design that incorporates a pivot with a main bore and radial groove to house part of the heating element's second portion, reducing its length and interactions with the pitch change system, and uses a robust connection system with a support member to simplify assembly and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the power cable is made longer to accommodate the rotational movement of the stator blades during pitch change, then the heating element can be properly positioned and connected, but the power cable interacts with the pitch change system causing mechanical stress and deformation
Solution Approach 1:
The power cable is routed through the pivot structure, utilizing the existing pivot bore and radial groove to guide and protect the cable. This nesting approach allows the cable to be accommodated within the pivot geometry, reducing external interactions and mechanical stress while maintaining proper positioning and connection of the heating element.
2Reliability
If spacers are used to avoid interactions between the power cable and pitch change system, then the power cable is protected from mechanical stress, but significant bulk is introduced in an area already constrained in terms of available space
Solution Approach 1:
Instead of adding external spacers that consume additional space, the solution nests the power cable within the existing pivot structure. The pivot bore and radial groove provide the protective pathway, eliminating the need for separate spacer components and reducing overall space occupation while maintaining cable protection.
3Ease of manufacture
If the heating element and electrical connection device are assembled in the restricted space of the turbomachine, then the installation can be completed, but the assembly becomes complex and the mechanical strength of power cables and electrical connectors is compromised
Solution Approach 1:
The power cable is pre-routed and positioned within the pivot structure before final assembly of the heating element and electrical connection device. This preliminary action simplifies the subsequent assembly steps by pre-establishing the cable pathway, reducing the complexity of installing components in the restricted space while maintaining mechanical strength.
4Temperature
If the power cable is exposed to open air, then heat transfer from the heating element can occur, but the lack of cooling limits the electrical power circulating in the power cables and reduces power density
Solution Approach 1:
The power cable is routed through the pivot structure, which provides a confined pathway that naturally channels heat away from the cable. This nesting arrangement improves heat transfer efficiency by creating a thermal pathway that prevents heat accumulation in the cable, thereby increasing the electrical power density that can be safely circulated.
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 design reduces mechanical stress, improves durability and reliability of heating elements, simplifies assembly, and enhances heat transfer, leading to weight savings and cost-effectiveness while maintaining reliable blade timing changes.
Implementation Method 1
a heating element comprising a first portion mounted within the blade and a second portion, extending outside the blade, connected to an electrical connection device
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a turbomachine assembly with a longitudinal axis (X), for an aircraft, comprising: - a variable-pitch stator vane (2) comprising a blade and a pivot (5) extending radially from the blade (4), and - a heating element (26) comprising a first portion (26a) mounted in the blade (4) and a second portion (26b) connected to an electrical connection device (29). According to the invention, the pivot comprises a main bore (33), a bore (34) passing through the wall of the pivot to open into the main bore (33) and onto an external surface of the pivot (5), and a radial groove (35) formed in the wall of the pivot which opens onto the external surface and into an outlet of the bore (34), the second portion (26b) extending the first portion (26a) and extending into the main bore (33), into the bore (34) then into the radial groove (35) towards the electrical connection device.