Turbomachine Combustion Shell Deflector Cooling
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Solution Overview
Problem
The existing combustion chamber designs for turbomachines experience decreased cooling efficiency due to obstacles created by spark plug guide means, leading to burning and crack initiation phenomena, which weaken the structure of the shell.
Innovation Solution
An annular shell with deflectors extending circumferentially downstream of projecting elements, featuring perforations between the elements and deflectors, redirects air flow to improve cooling efficiency by capturing and guiding cooling air to critical areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If spark plug guide means are installed in the outer shell, then the spark plug can be properly positioned and attached, but the cooling air flow is disrupted and cooling efficiency decreases
Solution Approach 1:
The outer shell surface is segmented into multiple zones: a first zone with the guide means for spark plug positioning, and a second zone with deflectors that redirect cooling air flow. This segmentation allows the guide means to perform its positioning function without completely blocking the cooling air flow, as the deflectors in the second zone can guide air around the obstacle.
Solution Approach 2:
Deflectors are introduced as intermediary elements between the guide means obstacle and the cooling air flow. These deflectors act as mediators that capture the cooling air flow diverted by the guide means and redirect it toward the area downstream of the guide means, thereby maintaining cooling efficiency despite the presence of the guide means.
2Reliability
If cooling air flow is increased to improve cooling efficiency, then burning and crack initiation are reduced, but the air flow is disrupted by the guide means obstacle
Solution Approach 1:
The deflectors are designed to dynamically adapt to the cooling air flow pattern. By positioning the deflectors in the second zone downstream of the guide means, they automatically capture and redirect the air flow that is naturally diverted by the guide means obstacle, creating a dynamic response to the flow disruption without requiring complex control mechanisms.
3Reliability
If the guide means obstacle is removed to improve cooling air flow, then cooling efficiency increases, but spark plug positioning capability is lost
Solution Approach 1:
The outer shell is designed with local quality differentiation: the first zone contains the guide means with specific geometric features for spark plug positioning, while the second zone contains deflectors optimized for air flow redirection. This local differentiation allows each zone to perform its specific function optimally without compromising the other.
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 solution significantly enhances cooling efficiency by maximizing air flow capture and heat exchange in areas downstream of projecting elements, reducing the risk of burning and crack initiation, thereby strengthening the shell structure.
Implementation Method 1
The deflectors are downstream of the projecting element with respect to a direction of gas flow along the outer wall, oriented along a longitudinal axis
Implementation Method 2
perforations being provided in the shell, axially between the projecting element and the or each deflector, the perforations opening at the level of the inner wall and the outer wall
Implementation Method 3
The cooling air flows axially in the downstream direction along the outer wall of the outer shell
Data Source
AI summary
An assembly for a combustion chamber of a turbomachine. The assembly comprises an annular shell extending along a longitudinal axis, the shell having an inner wall intended to be turned towards a furnace of the combustion chamber and an outer wall opposite the inner wall and a projecting element extending radially from an area of the outer wall. The shell has at least one deflector projecting from the outer wall and located downstream of the projecting element with respect to a direction of gas flow along the outer wall, oriented along the longitudinal axis. The deflector extends circumferentially. Perforations are provided axially between the projecting element and the or each deflector.