Gas Turbine Combustor Heat Shield Cooling Air Distribution
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Solution Overview
Problem
Existing heat shields in gas turbine engine combustors face challenges in efficiently cooling the dome panel while minimizing coolant usage to reduce smoke, unburned hydrocarbon, and CO/NOx emissions.
Innovation Solution
A heat shield design featuring a body with a fuel nozzle hole, a back face mounted adjacent to the combustor dome, a ridge extending around the nozzle opening, and a plurality of slots that direct pressurized cooling air through impingement holes and fluid passages to cool the exterior of the heat shield, optimizing airflow and heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If more coolant is used to cool the heat shield, then the cooling efficiency is improved, but the combustion efficiency deteriorates and emissions increase
Solution Approach 1:
The heat shield incorporates different cooling mechanisms in different regions: impingement cooling holes in the central annular area for direct cooling, and slots in the ridge for film cooling of adjacent regions. This localized cooling approach optimizes coolant distribution to achieve efficient heat shield cooling while minimizing overall coolant consumption that would otherwise reduce combustion efficiency and increase emissions.
2Object-generated harmful factors
If coolant usage is minimized to improve combustion efficiency, then emissions are reduced, but heat shield cooling effectiveness deteriorates
Solution Approach 1:
The cooling system is segmented into multiple functional components: impingement cooling holes for direct cooling of the back face, slots in the ridge for film cooling of the exterior surface, and a cooling compartment for coolant storage and distribution. This segmentation allows each component to perform its specific cooling function efficiently, achieving effective heat shield temperature control with minimized overall coolant usage, thereby reducing emissions while maintaining combustion efficiency.
3Device complexity
If a simple heat shield design is used, then device complexity is reduced, but cooling efficiency deteriorates
Solution Approach 1:
The heat shield design integrates multiple cooling functions into a single unified structure. The ridge serves both as a structural element and as a coolant distribution channel with embedded slots. The cooling compartment serves as both a coolant reservoir and a flow distribution system. This multi-functionality approach achieves efficient cooling without proportionally increasing device complexity, as the same structural elements perform multiple cooling-related functions.
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 enhances cooling efficiency, reduces emissions, and minimizes coolant usage by effectively directing cooling air to critical regions of the heat shield, improving combustion efficiency and reducing smoke and pollutant emissions.
Implementation Method 1
the slots adapted to direct pressurized cooling air within the compartment therethrough to cool an adjacent region of the body exterior of the compartment
Implementation Method 2
direct pressurized cooling air within the compartment therethrough to cool an adjacent region of the body exterior
Data Source
AI summary
A combustor heat shield has a body defining a fuel nozzle hole. The back face of the body is mounted adjacent and spaced-apart from a combustor dome. A ridge extends around the nozzle opening to a height adapted to substantially contact the combustor dome. The ridge thereby defines a cooling compartment between the body and the combustor dome. A plurality of slots is provided through the ridge. The slots are closed by the combustor dome to provide cooling holes when the heat shield is mounted on the combustor. The cooling holes direct pressurized cooling air from the compartment to adjacent regions of the back face of the heat shield body.