Rocket Combustion Chamber Vortex Heat Transfer

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Solution Overview

Problem

Conventional rocket engine propulsion chambers face challenges in efficiently cooling smooth inner walls due to high temperatures, as existing methods like fin devices and chevrons are ineffective for non-corrugated combustion chambers, leading to suboptimal heat flux extraction and thermomechanical stress.

Innovation Solution

The implementation of longitudinal vortex generators on the internal wall of the combustion chamber, which mix hot gas streams of different temperatures and create longitudinal vortices to enhance convective heat transfer without increasing the surface area, combined with fins upstream to further improve heat flux extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If fin devices or chevrons are used to increase heat transfer surface area, then heat transfer efficiency improves, but this solution is ineffective for smooth non-corrugated combustion chambers

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidapplicability to smooth chambers
Core Design Contradiction:
TemperatureVSAdaptability or versatility

Solution Approach 1:

The invention changes the flow regime parameter by introducing longitudinal vortices through vortex generators. Instead of relying on increased surface area through fins or chevrons, the solution modifies the convective heat transfer mechanism by creating rotational flow patterns that enhance mixing and heat transfer coefficients in smooth combustion chambers.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical surface area extension approach (fins, chevrons) with a flow control mechanism (vortex generators). The mechanical structure of fins is substituted by a more compact vortex-generating element that achieves heat transfer enhancement through fluid dynamic effects rather than surface area multiplication.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Temperature

If conventional cooling circuits are used, then chamber walls can be cooled, but heat flux extraction is insufficient leading to thermomechanical stress

Engineering Contradiction:
Improvewall temperature controlVSAvoidthermomechanical performance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The vortex generators are positioned upstream in the combustion chamber to pre-condition the hot gas flow before it reaches the critical wall sections. By creating vortices and enhancing mixing in advance, the heat transfer is improved in the regions where it is most needed for wall cooling and thermomechanical stability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The vortex generators create localized regions of enhanced heat transfer at specific positions in the combustion chamber. The flow modification is applied locally where needed, creating rotational flow patterns that intensify convective heat transfer in critical wall sections without requiring global changes to the cooling system.

Inventive Principle:
Principle #3Local quality

3Power

If heat extraction from cooling circuit is maximized, then turbine efficiency increases, but this may compromise chamber wall cooling

Engineering Contradiction:
Improveturbine efficiencyVSAvoidchamber wall temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The invention segments the heat transfer enhancement function from the cooling circuit function. Vortex generators are installed in the hot gas path to enhance convective heat transfer independently, allowing the cooling circuit to operate more efficiently by extracting heat without compromising wall cooling, as the vortex generators have already improved the overall heat transfer rate.

Inventive Principle:
Principle #1Segmentation

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 solution increases the convective exchange coefficient, leading to improved heat flux extraction with reduced thermal gradients and enhanced thermomechanical resistance, thus optimizing the cooling efficiency and overall performance of the rocket engine.

Implementation Method 1

the hot gas flows vortex along the longitudinal axis along the inner wall in order to increase the heat transfers between the hot gas flows and the inner wall of the combustion chamber

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

a plurality of flow vortex generators located on the inner wall inside the body of the combustion chamber and configured so that the hot gas flows vortex along the longitudinal axis

Methodology Applied
Scientific EffectVortex: Vortex Generator

Implementation Method 3

a heat transfer fluid is circulated which cools the wall of the chamber

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 4

the heat extracted from the cooling circuit is also used to power the turbines of the turbopumps

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3156636B1Propulsion system with improved heat transfer
Publication Date: 2021.11.03 CENT NAT DETUD SPATIALES (CNES)
  • EP3156636B1 patent drawingFigure 1
  • EP3156636B1 patent drawingFigure 2a~2b
  • EP3156636B1 patent drawingFigure 3

AI summary

The invention relates to a rocket propulsion system comprising a combustion chamber in which combustion is carried out and which is connected by a throat to a diverging nozzle, and in which hot gases (GC) flow along a longitudinal axis (AA) of the combustion chamber, the combustion chamber comprising an inner wall (1') and an outer wall (1") defining a cavity inside which a heat transfer fluid flows to cool the combustion chamber (1); a plurality of flow vortex generators (10) located on the inner wall (1') inside the combustion chamber body and configured so that the hot gases flow in a vortex fashion along the longitudinal axis (AA) along the inner wall in order to increase heat transfers between the hot gases and the combustion chamber.