Conical Combustion Chamber Deflector for Uniform Cooling

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Solution Overview

Problem

In convergent combustion chambers, the significant inclination of the combustion chamber and reduced number of injectors or small diameter lead to a variable distance between the chamber bottom and thermal protection screens, causing assembly issues and inadequate cooling, which can result in contact between these components.

Innovation Solution

A deflector designed as a conical plate with a concave and convex face, featuring a central and peripheral zone with a constant distance from the chamber bottom, equipped with angular positioning means such as locking grooves and stop pins to maintain parallelism and ensure consistent cooling air flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the combustion chamber has significant inclination (convergent design), then the combustion chamber can accommodate reduced number of injectors or small diameter, but the distance between chamber bottom and deflectors becomes variable causing assembly issues and inadequate cooling

Engineering Contradiction:
Improvecombustion chamber configuration flexibilityVSAvoiddeflector positioning accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The deflector is designed with a conical shape matching the chamber bottom geometry, allowing it to maintain a constant distance from the chamber bottom surface across varying inclinations. This curvature adaptation enables the deflector to conform to the convergent chamber design while ensuring uniform cooling air gap and proper positioning.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The deflector geometry parameters (cone angle, radius) are specifically designed to match the chamber bottom inclination parameters. By changing the deflector's geometric parameters to correspond with the chamber's convergent angle, the system maintains constant spacing despite the inclined configuration, resolving the positioning accuracy issue.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the distance between chamber bottom and deflectors is variable, then assembly may be simplified, but cooling effectiveness deteriorates due to inconsistent air flow distribution

Engineering Contradiction:
Improveassembly simplicityVSAvoiddeflector cooling uniformity
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The conical shape of the deflector ensures that the distance to the chamber bottom remains constant across all radial positions, creating uniform cooling air gaps. This geometric design guarantees consistent cooling air flow distribution and uniform temperature distribution across the deflector surface.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Ease of manufacture

If flat deflectors are used in highly inclined chambers, then manufacturing is simpler, but contact between bottom and deflectors occurs causing assembly failures

Engineering Contradiction:
Improvedeflector manufacturing simplicityVSAvoidassembly reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

By transitioning from flat to conical deflectors, the invention eliminates contact issues in inclined chambers. The curved surface maintains proper spacing throughout, preventing assembly failures while remaining manufacturable through standard conical forming processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 maintains a constant distance between the deflector and the chamber bottom, facilitating effective cooling and preventing assembly issues by ensuring consistent positioning and parallel alignment, thus enhancing the thermal protection and assembly of the combustion chamber.

Implementation Method 1

These air jets, flowing from upstream to downstream, are guided by chamber fairings, cross the bottom of the chamber 116 through the cooling orifices 124, and impact an upstream face of the deflectors 122

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

A deflector designed as a conical plate with a concave and convex face, featuring a central and peripheral zone with a constant distance from the chamber bottom

Methodology Applied
Scientific EffectGeometric shape: Geometry

Data Source

PatentEP1939528B1Deflector for the bottom of a combustion chamber, combustion chamber equipped with same and jet engine comprising them
Publication Date: 2016.06.22 SAFRAN AIRCRAFT ENGINES SAS
  • EP1939528B1 patent drawingFigure 1~11
  • EP1939528B1 patent drawingFigure 2~4
  • EP1939528B1 patent drawingFigure 5~6

AI summary

The deflector (22) is in the form of a plate with a hole (40). This plate is a portion of a conical surface of revolution about a cone axis (300), has a concave face (62) and a convex face (64), and a contour with four sides (72, 74, 76, 78). Two of these sides (72, 76) are concentric arcs of circles centered on the cone axis (300), and the other two sides (74, 78) are segments of the generatrices of the cone that connect the first two sides (72, 76). Application to a deflector (22) of a combustion chamber bottom (16) of a combustion chamber (10) of a turbojet engine (2).