Transition Nozzle Split Cooling Flow for Gas Turbine Efficiency
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Solution Overview
Problem
Transition nozzle combustion systems in gas turbine engines face inefficiencies due to parasitic cooling and leakage flows, which reduce overall performance and component lifetime by diverting cooling flow away from charging combustion gases.
Innovation Solution
A combustion system design that utilizes a split cooling flow, where a portion is directed through cooling holes and slots to minimize film cooling requirements near the choked flow region, allowing more cooling flow to participate in charging combustion gases, and incorporates thermal barrier coatings and high-performance materials to reduce cooling needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If film cooling is used to cool the transition nozzle near the choked flow region, then component lifetime is improved, but pressure losses increase and system efficiency decreases
Solution Approach 1:
The cooling flow is divided into two separate streams: a first cooling flow directed toward the head end of the transition nozzle and a second cooling flow directed toward the aft end. This segmentation allows each cooling flow to be optimized for its specific region, reducing overall pressure losses while maintaining effective cooling where needed.
Solution Approach 2:
Different cooling strategies are applied to different regions of the transition nozzle. The head end receives one cooling flow configuration while the aft end receives another, tailored to the specific thermal and flow conditions of each region. This local optimization minimizes parasitic cooling losses in the choked flow region while maintaining component lifetime.
2Duration of action of stationary object
If more cooling flow is used to cool the transition nozzle, then component lifetime is improved, but the flow available for charging combustion gases is reduced
Solution Approach 1:
The cooling flow is segmented into two distinct streams that are directed to different regions of the transition nozzle. This allows the cooling system to use minimal cooling flow where necessary (particularly in the choked aft region) while preserving the majority of the cooling flow capacity for charging combustion gases in the head end region.
Solution Approach 2:
Instead of applying full cooling flow throughout the entire transition nozzle, the invention applies partial cooling action only where thermally critical. The second cooling flow to the aft end is minimized since that region is already protected by the choked flow condition, allowing more cooling flow to be available for combustion charging.
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 reduces pressure losses and increases firing temperatures, enhancing overall system efficiency and performance by optimizing the use of cooling flow within the combustion system.
Implementation Method 1
a portion of the cooling flow may be used to cool the transition nozzle though film cooling
Implementation Method 2
incorporates thermal barrier coatings and high-performance materials to reduce cooling needs
Implementation Method 3
the transition nozzle and the associated support structures may require a cooling system to withstand the aerodynamic heat loads associated with the high Mach Number combustion gas flows
Data Source
Figure 1~2
Figure 3~5
AI summary
The present invention provides a combustion system for use with a cooling flow. The combustion system may include a head end, an aft end, a transition nozzle (110) extending from the head end to the aft end, and an impingement sleeve (160) surrounding the transition nozzle (110). The impingement sleeve (160) may define a first cavity (170) in communication with the head end for a first portion (210) of the cooling flow (200) and a second cavity (180) in communication with the aft end for a second portion (220) of the cooling flow (200). The transition nozzle (110) may include a number of cooling holes (230) thereon in communication with the second portion (220) of the cooling flow (200).