Double-Walled Combustion Chamber Cooling via Impingement and Convection
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Solution Overview
Problem
Current cooling methods for gas turbine combustor walls are inefficient, leading to reduced power and efficiency due to difficulty in cooling the hot gas duct walls and increased pressure drop in cooling gas supply, which can be detrimental to the overall performance of the gas turbine.
Innovation Solution
A double-walled combustion chamber design with a cavity and sleeve system that uses compressed cooling gas to impinge on the duct wall, allowing for both impingement cooling and convective cooling, with the ability to reuse cooling gas for further heat transfer, reducing pressure loss and increasing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling sleeves with impingement cooling are used to cool combustor walls, then cooling effectiveness is improved, but pressure drop increases and power output decreases
Solution Approach 1:
The cooling system is segmented into multiple functional zones: impingement cooling zones with arrays of holes for direct cooling, and serpentine cooling channels for convective cooling. This segmentation allows different cooling mechanisms to work in conjunction, improving overall cooling effectiveness while optimizing pressure drop characteristics.
Solution Approach 2:
The cooling approach transitions from single-dimension convective cooling to multi-dimensional cooling by adding impingement cooling (perpendicular to wall surface) combined with serpentine path convective cooling (parallel to wall surface). This multi-dimensional approach enhances cooling effectiveness without proportionally increasing pressure drop.
2Volume of stationary object
If cooling gas supply channels are reduced in cross section to fit space constraints, then space utilization is improved, but pressure drop increases
Solution Approach 1:
The cooling channel geometry dynamically adapts through serpentine paths that optimize flow characteristics. The varying cross-section and path length of serpentine channels create favorable pressure gradients that reduce overall pressure drop while maintaining effective cooling coverage within limited space.
Solution Approach 2:
The serpentine cooling channels act as intermediaries between the impingement cooling zones and the exhaust, providing a extended cooling path that increases cooling effectiveness without requiring additional plenum space or excessive pressure increase.
3Temperature
If impingement cooling is provided from all circumferential directions, then cooling coverage is improved, but device complexity increases
Solution Approach 1:
The cooling sleeves serve multiple functions: they provide impingement cooling through arrays of holes, guide serpentine cooling channels for convective cooling, and direct cooled gas into the combustion chamber. This multi-functionality reduces the need for separate cooling components, simplifying overall system structure while maintaining comprehensive cooling coverage.
Solution Approach 2:
The impingement cooling and convective cooling systems are merged into an integrated cooling arrangement where cooling gas flows sequentially through impingement zones and serpentine channels. This combination achieves comprehensive wall cooling from multiple directions without requiring entirely separate cooling systems for each zone.
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 proposed design enhances cooling efficiency, reduces pressure loss, and allows for flexible adjustment of cooling capacity, leading to increased gas turbine efficiency and power output while minimizing NOx emissions.
Implementation Method 1
guides a cooling gas in a cooling channel between the sleeve and the duct wall along the outer surface of the duct wall
Implementation Method 2
The cooling gas further cools the duct wall as it flows through the cooling channel towards the exit end of the cooling channel
Implementation Method 3
The impingement sleeve contains an array of holes through which compressed cooling gas discharges to generate an array of air jets which impinge on and cool the outer surface of the duct
Data Source
AI summary
A combustion chamber includes a duct wall for guiding a hot gas flow in a hot gas flow path during operation. The duct wall is a double-walled construction including an inner face, an outer face, and a wall cavity. A sleeve at least partly encloses the duct wall for guiding a cooling gas in a cooling channel between the sleeve and the duct wall along the outer surface of the duct wall to an exit end, and the cavity opens to the cooling channel. A gas turbine is disclosing as having such a combustion chamber.