Turbomachine Combustion Chamber with Alternating Orifice Diameters
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Solution Overview
Problem
Conventional turbomachine combustion chambers are bulky and require a large number of injectors and bowls, failing to achieve an optimal compromise between idle and full-throttle operations while also emitting harmful gases like nitrogen oxides and carbon dioxide.
Innovation Solution
A combustion chamber design featuring a single annular row of air injection orifices with alternating smaller and larger diameter orifices, optimized for different operating speeds, reduces the number of injectors and bowls by creating two coaxial layers with distinct opening angles, ensuring efficient combustion and homogeneous mixture distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional combustion chamber uses a single annular row of mixing bowls with uniform air injection orifices, then the structure is simple, but it cannot achieve optimal performance across different operating speeds (idle and full-throttle)
Solution Approach 1:
The patent applies local quality by dividing the air injection orifices into two distinct groups with different diameters (first group and second group) within the same annular row. Each group is positioned at specific angular intervals and has optimized dimensions for particular operating conditions, allowing the single row to deliver location-specific airflow characteristics that adapt to different throttle positions without requiring multiple separate rows of bowls.
2Adaptability or versatility
If a combustion chamber uses two coaxial annular rows of mixing bowls (idle head and take-off head) to optimize different operating speeds, then performance across speeds is improved, but the chamber becomes bulky and requires a large number of injectors and bowls
Solution Approach 1:
The patent merges the functions of two separate annular rows of mixing bowls into a single annular row by incorporating two groups of air injection orifices with different diameters. This consolidation maintains the ability to optimize for both idle and full-throttle operations while reducing the overall number of bowls and injectors required, thereby decreasing the combustion chamber volume and eliminating the bulkiness associated with dual-row configurations.
Solution Approach 2:
The single annular row of mixing bowls is designed to perform multiple functions by incorporating two groups of air injection orifices that can serve different operating conditions. The first group of orifices optimizes airflow for idle operation, while the second group optimizes for full-throttle operation, allowing one structural element to replace what would traditionally require two separate rows of bowls.
3Device complexity
If a combustion chamber uses a single annular row of mixing bowls with uniform air injection orifices, then the number of injectors is reduced, but the mixture distribution becomes non-homogeneous and temperature gradients occur
Solution Approach 1:
The patent addresses mixture homogeneity by implementing local quality variations through two groups of air injection orifices with different diameters positioned at specific angular intervals. This localized differentiation of airflow characteristics ensures that air-fuel mixing occurs more uniformly across the combustion chamber, preventing temperature gradients and non-homogeneous combustion that would result from using uniform orifices throughout.
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 turbomachine performance across various speeds, reduces harmful gas emissions, and allows for a reduced number of injectors and bowls, achieving a more compact and efficient combustion process.
Implementation Method 1
a substantially frustoconical wall formed with an annular row of air injection orifices which are regularly distributed around the axis of the bowl... to produce an annular layer of a mixture of air and fuel
Implementation Method 2
a combustion chamber of a turbomachine... intended to be ignited in the primary zone of the chamber
Data Source
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AI summary
The chamber has a mixing bowl (95) with a cylindrical wall (118) formed with a row of annular air injection orifices regularly distributed around an axle of the bowl. A fuel injector (36) is arranged in upstream of the bowl, and the row of annular air injection orifices comprises orifices (140) of small diameter and orifices (142) of large diameter, where the orifices are alternately arranged and regularly distributed around the axle for forming fuel and air mixture annular layers (144, 148) have large and small opening angles, respectively.