Air Intake Ring Discontinuity for Fuel Atomization
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Solution Overview
Problem
Conventional air intake rings in turbomachine combustion chambers produce large fuel droplets that have limited space to evaporate, resulting in suboptimal combustion efficiency due to insufficient evaporation volume and mixing with air.
Innovation Solution
An air intake ring with an annular separation wall featuring a discontinuity in its internal profile, which increases the radius downstream, causing fuel to separate into droplets further upstream and creating a recirculation area that enhances turbulence and mixing with air, allowing for improved evaporation and combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the air intake ring uses a conventional smooth internal profile, then the structure is simple and easy to manufacture, but the fuel droplets are large and have limited evaporation volume
Solution Approach 1:
The internal profile is segmented into multiple zones: an upstream convergent section, a discontinuity feature (shoulder or step), and a downstream divergent section. This segmentation creates distinct flow regions that control fuel atomization and droplet formation, producing smaller droplets with improved evaporation characteristics without requiring complete redesign of the entire structure.
Solution Approach 2:
The discontinuity feature in the internal profile preliminarily accelerates and directs the air flow before it reaches the fuel injection zone. This pre-conditioning of the air flow ensures that when fuel is injected, it is immediately subjected to high-velocity turbulent flow, enhancing atomization and creating smaller droplets upstream rather than allowing large droplets to form downstream with limited evaporation space.
2Productivity
If the fuel separates downstream in the conventional design, then the structure is compact, but the evaporation volume is limited and combustion efficiency is reduced
Solution Approach 1:
The discontinuity feature introduces a radial dimension change in the internal profile, creating a step or shoulder that protrudes radially inward. This dimensional change forces the air flow to expand and creates a recirculation zone, increasing the effective volume available for fuel evaporation and mixing before combustion, thereby improving combustion efficiency without increasing the overall combustor size.
3Quantity of substance
If the internal profile is smooth and continuous, then the flow is stable, but the fuel-air mixing is insufficient and droplet formation is poor
Solution Approach 1:
The internal profile transitions from a static smooth design to a dynamic flow-conditioning structure with a discontinuity feature. This feature creates controlled flow separation and recirculation zones that enhance turbulent mixing of fuel and air. The discontinuity acts as a flow control element that dynamically adjusts the mixing process, creating intense local turbulence for better atomization while maintaining overall flow stability through the convergent-divergent geometry.
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 solution results in smaller fuel droplets with a larger evaporation volume, improved mixing, and increased combustion efficiency, reducing lean extinction proportions and CO/CH emissions.
Implementation Method 1
Said air flow 78 induces a shearing effect which results in the fuel separating from the annular deflection wall so as to form droplets suspended in the air
Implementation Method 2
the discontinuity creates a recirculation area downstream thereof and induces turbulence, which favours the mixing of the fuel with the air
Implementation Method 3
The fuel droplets separated from the annular deflection wall are intended to evaporate into the air, preferably before reaching the interior of the combustion chamber
Data Source
AI summary
A system for improving fuel-air mixing inside an injection system of a turbomachine combustion chamber. An air intake ring has an annular deflection wall, or venturi, having an internal profile provided with a discontinuity inducing an increase in the radius (φ) of the internal profile downstream of the discontinuity. A method of atomizing fuel includes separating fuel trickling over the internal profile of the annular deflection wall from the internal profile at the level of the discontinuity so as to form droplets within a flow of air coming from an upstream air circulation space of the air intake ring.