CMC Turbine Nozzle with Mast Load Spreading
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ceramic matrix composite (CMC) nozzles in turbomachines face challenges in deterministic retention of nozzle sectors under high aerodynamic and pressure differential loads, which can lead to material stress and sealing issues due to differential thermal dilation and high stiffness sensitivity.
Innovation Solution
A turbomachine design featuring a metal outer and inner support shroud with a mast system that allows for independent deformation of CMC nozzle sectors, enhanced sealing through hollow profiles and fastening projections, and anti-rotation features to manage pressure and aerodynamic loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC nozzle sectors are used to increase temperature tolerance and reduce cooling air, then the maximum temperature tolerated is improved, but the deterministic retention of nozzle sectors under high aerodynamic and pressure differential loads deteriorates
Solution Approach 1:
The nozzle is divided into multiple CMC sectors that are assembled together to form a complete ring. Each sector can deform independently under thermal and mechanical loads, which prevents stress concentration and improves the overall reliability of the nozzle assembly while maintaining high temperature tolerance.
Solution Approach 2:
A metal backing structure is introduced as an intermediary element between the CMC nozzle sectors and the turbine casing. This backing structure absorbs and distributes the high aerodynamic and pressure differential loads, protecting the CMC sectors from excessive stress while allowing them to maintain their temperature tolerance advantages.
2Temperature
If CMC material is integrated in a metal environment, then the temperature performance is improved, but the differential thermal dilation between materials worsens
Solution Approach 1:
The nozzle is segmented into multiple CMC sectors with metal backing structures. This segmentation allows each sector to expand and contract independently with temperature changes, accommodating differential thermal dilation between CMC and metal materials while maintaining overall structural integrity and temperature performance.
3Temperature
If CMC material is used for high-pressure nozzle, then the temperature resistance is improved, but the sensitivity to mechanical stresses worsens
Solution Approach 1:
A metal backing structure serves as an intermediary that bears the high mechanical stresses from aerodynamic loads and pressure differentials. The CMC nozzle sectors rest on this backing structure, which protects them from excessive stress while allowing the CMC material to充分发挥 its temperature resistance advantages.
Solution Approach 2:
Dividing the nozzle into multiple CMC sectors with metal backing reduces the mechanical stress on each individual CMC component. The segmented design allows for better stress distribution and prevents catastrophic failure, addressing the sensitivity of CMC to mechanical stresses while maintaining high temperature resistance.
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 design simplifies assembly, improves sealing, and reduces material stress by allowing independent deformation of CMC nozzle sectors while maintaining structural integrity and performance under high loads, thereby enhancing the operational efficiency and reliability of turbomachines.
Implementation Method 1
differential thermal dilations between the CMC and the metal
Implementation Method 2
allowing the sectors to deform independently of the interfaced metal parts
Implementation Method 3
a high pressure differential is exerted on the casing under the nozzle in the radial and axial directions
Data Source
AI summary
Turbine comprising a casing and a nozzle including a metal outer shroud integral with the casing, a metal inner shroud, and a plurality of nozzle sectors of CMC forming a ring extending between the metal outer shroud and the metal inner shroud, each sector including a mast, an inner platform, an outer platform and at least one airfoil having a hollow profile defining an inner recess, each of the inner and outer platforms having an opening communicating with said inner recess, and the mast passing through said openings and the inner recess and being attached to said casing and connected with said nozzle sector. The mast comprises at least one fastening projection having at least one portion extending from a radially outer end of the mast in a direction opposite to the center of the mast and in a plane orthogonal to the radial direction.