Turboengine Combustion Chamber Divergent Cooling
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Solution Overview
Problem
Existing combustion chambers in turbojet engines face challenges in effectively cooling the divergent part of the combustion bowl due to inefficient air flow and fuel atomization, leading to high thermal and mechanical stresses.
Innovation Solution
A turbomachine combustion chamber design featuring a double partition divergent bowl with staggered inlet and outlet orifices arranged in circular rows, promoting effective air circulation and fuel mixture spraying through tangential incidence and swirling, which enhances cooling and atomization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air flow is slowed down in the cavity to cool the divergent part, then cooling effect is improved, but air flow speed decreases causing the air to heat up and reducing cooling effectiveness
Solution Approach 1:
The divergent part is divided into multiple sections with staggered inlet and outlet orifices arranged in circular rows. This segmentation allows the air flow to be distributed across multiple cooling zones, maintaining high flow speed while providing comprehensive cooling coverage throughout the divergent part.
Solution Approach 2:
Cooling orifices are strategically positioned at different locations (staggered in circular rows) along the divergent part. Each local region receives targeted cooling air injection, ensuring effective cooling throughout the entire divergent section while maintaining overall high air flow speed.
2Temperature
If outlet channel is arranged at a distance from inlet orifices to cool the divergent, then cooling coverage is improved, but air flow heats up during passage reducing cooling efficiency
Solution Approach 1:
The cooling system is segmented into multiple inlet and outlet orifice groups arranged in staggered circular rows. This creates multiple short cooling paths rather than one long path, reducing the distance air travels and minimizing heat gain during passage while maintaining extensive cooling coverage.
Solution Approach 2:
The cooling orifices are arranged in circular rows with tangential incidence, creating a three-dimensional cooling pattern around the divergent part. This radial-circular arrangement provides comprehensive cooling coverage while keeping flow paths short and efficient.
3Temperature
If air flow is used to cool the divergent part, then cooling effect is improved, but fuel atomization and spraying quality deteriorate
Solution Approach 1:
The cooling function is segmented into dedicated cooling orifices separate from the fuel injection system. Cooling air is injected through specific inlet and outlet orifices in the divergent part, while fuel is injected separately through the injector device, allowing both cooling and atomization functions to operate optimally without interference.
Solution Approach 2:
Different regions of the divergent part are assigned different functions: cooling orifices are positioned to provide cooling in specific zones, while the fuel injector is positioned to optimize fuel atomization in the combustion zone. This spatial separation of functions allows each to perform its role effectively.
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 allows for efficient cooling of the divergent part and improved fuel mixture spraying, reducing thermal stresses and preventing hot spots, while maintaining high air flow speed to prevent heating and enhance combustion efficiency.
Implementation Method 1
the first outer wall having inlets arranged to cool the second inner wall by impact
Implementation Method 2
The cooling air, entering through the inlet orifices in the annular cavity and emerging through the outlet orifices, is advantageously swirled, which creates turbulence promoting the spraying and shearing of the fuel mixture
Implementation Method 3
the air flow... is then expelled into the combustion chamber to assist in fuel atomization
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a turbomachine combustion chamber (1) comprising a chamber bottom which has at least one opening for receiving a combustion bowl (30) in the axis of which is mounted an air and fuel injection device, said flared bowl (30) having downstream a divergent (31) consisting of a double partition delimiting an annular cavity (35), - the first outer partition (33) having inlet ports (331) arranged to cool by impact the second inner partition (34); - the second inner partition (34) having outlet ports (332); chamber characterized in that the inlet ports (331), distributed in at least two circular rows around the periphery of the divergent (31), are staggered with the outlet ports (332).