Aircraft Combustion Chamber Outer Port Discharge Coefficient
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Solution Overview
Problem
The existing design of annular combustion chamber modules in turbomachines does not optimize air distribution from primary and dilution ports, leading to inefficiencies in air flow and pressure loss, particularly due to the geometry and discharge coefficients of the ports.
Innovation Solution
The combustion chamber module enhances air distribution by increasing the discharge coefficient and cross-sectional area of outer ports located in the wake of fuel injectors, ensuring they have a higher discharge coefficient than their inner counterparts, which compensates for pressure losses and provides better air homogeneity within the chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If outer ports are positioned in the wake of fuel injectors, then air flow through outer ports is improved, but pressure loss increases due to wake effects
Solution Approach 1:
The patent applies local quality by differentiating the discharge coefficients of outer ports based on their location relative to injector wakes. Outer ports positioned in wakes have higher discharge coefficients (increased by 2-5%) compared to those outside wakes, allowing localized compensation for pressure losses while optimizing overall air distribution.
Solution Approach 2:
The invention changes the discharge coefficient parameter of outer ports located in injector wakes by increasing it by 2-5% relative to ports outside wakes. This parameter modification compensates for the adverse wake effects and achieves more homogeneous air distribution across the combustion chamber.
2Stability of the object's composition
If discharge coefficient of outer ports is increased to compensate for wake effects, then air distribution homogeneity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements local quality by applying different discharge coefficients to outer ports based on their circumferential position relative to injector wakes. This localized differentiation improves air distribution homogeneity while maintaining a relatively simple overall port geometry structure.
Solution Approach 2:
The invention modifies the discharge coefficient parameter of specific outer ports (those in wakes) by 2-5% to achieve homogeneous air distribution. This targeted parameter change avoids the need for complex geometric modifications across all ports, thereby limiting manufacturing complexity.
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 improves air distribution homogeneity and compensates for pressure losses, optimizing the air flow and thermal profile for efficient energy extraction in turbomachines, with discharge coefficient increases ranging from 2% to 5% for outer ports compared to inner ports.
Implementation Method 1
a third part aims at bypassing the combustion chamber by running between said injectors, which thus each create a respective wake
Implementation Method 2
each of the outer ports which is located at least partly in the wake of one of the injectors, has a discharge coefficient higher than that of its homologous inner port
Data Source
AI summary
A combustion chamber module for an aircraft turbomachine, including an annular combustion chamber in which each of primary and dilution ports of an outer annular wall, which is located at least partly in a wake of a fuel injector, has a discharge coefficient higher than that of its homologous port of an inner annular wall. A method for designing such a module includes determining wakes generated by fuel injectors, and then geometrically defining air inlet ports of coaxial walls of the combustion chamber such that an air flow rate actually entering through ports of the outer wall is substantially equal to an air flow rate entering through ports of the inner wall.