Hybrid Floatwall Cooling Feature Combats Hot Spot Damage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turbine engine combustor walls face material fatigue and hot spot formation due to varying combustion chamber gas temperatures and debris deposits, leading to reduced cooling effectiveness and potential wall deterioration.
Innovation Solution
A hybrid double wall system with strategically placed shaped pads of increased thickness on the heat shield, incorporating impingement and effusion apertures to enhance cooling fluid flow and prevent hot spot propagation, while maintaining complex cooling passages and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling passages are made more complex to improve cooling effectiveness, then cooling performance improves, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating a hybrid floatwall feature with varying thickness - thicker in regions requiring enhanced cooling (to accommodate complex cooling passages) and thinner in other regions. This allows complex cooling passages to be placed only where thermally critical, improving cooling effectiveness without unnecessarily increasing overall device complexity.
2Reliability
If heat shield thickness is increased to prevent hot spot propagation, then durability improves, but weight increases
Solution Approach 1:
The hybrid floatwall feature provides localized thickness variation in the heat shield. The thickness is increased only in specific regions where hot spots are expected or where cooling passages require support, while other regions maintain original thickness. This prevents hot spot propagation in critical areas without unnecessarily increasing overall heat shield weight.
Solution Approach 2:
The heat shield is segmented into regions of different thicknesses based on thermal requirements. The hybrid floatwall creates distinct thick and thin zones, allowing the structure to provide enhanced hot spot resistance only where needed rather than uniformly throughout the entire heat shield.
3Reliability
If cooling air flow is increased to maintain cooling effectiveness, then cooling performance improves, but energy loss increases
Solution Approach 1:
The hybrid floatwall feature enables concentrated cooling passages in thick regions to be more efficient at cooling per unit of air flow. By placing complex passages only where thermally critical, the system achieves effective cooling with optimized air distribution rather than requiring high overall air flow, thus reducing energy loss.
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 hybrid double wall system significantly reduces hot spot damage, extends heat shield life by slowing panel burn-through, and maintains cooling effectiveness, making the system insensitive to debris and improving material durability.
Implementation Method 1
The support shell can include a plurality of impingement apertures, which directs cooling air from a plenum surrounding the combustor into the impingement cavity and against an impingement cavity surface of the heat shield.
Implementation Method 2
The heat shield can include a plurality of effusion apertures, which directs the cooling air from the impingement cavity into the combustion chamber for film cooling a combustion chamber surface of the heat shield.
Implementation Method 3
A hybrid floatwall cooling feature can be provided in the combustor wall. The hybrid floatwall cooling feature can include a shaped pad formed in the heat shield and extending through a cutout formed in the support shell.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A combustor wall for a turbine engine with an axial centerline comprising a combustor support shell (30) comprising a plurality of impingement apertures (44), a combustor heat shield (32) comprising a plurality of effusion apertures (96) fluidly coupled with the plurality of impingement apertures (44), and at least one shaped pad (110) formed in said combustor heat shield (32), said at least one shaped pad (110) extending through a cutout (114) in said combustor support shell (30).