Rocket Engine Ground Ignition via Destructible Tubular Guide

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Solution Overview

Problem

Conventional rocket engine ground ignition methods result in significant axial and lateral loads that can damage components due to asymmetrical ignition, leading to increased costs and maintenance needs, particularly with intrusive ignition torches.

Innovation Solution

A rocket engine with an axisymmetric propulsion chamber and a destructible, thermally resistant tubular guide that channels propellants around the axis of symmetry, allowing for controlled ignition closer to the axis and reducing lateral loads by absorbing detonation energy, which is lightweight and made of materials like plastic or thermally insulating fabrics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If conventional ground ignition with torches is used, then on-board mass and cost are reduced by dispensing with internal ignition device, but significant axial and lateral loads occur that can damage engine components

Engineering Contradiction:
Improveon-board massVSAvoidcomponent strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

A tubular guide is introduced as an intermediary component between the propellant flow and the ignition torches. This guide channels the propellants in a controlled manner and positions the ignition zone closer to the axis of symmetry, thereby mediating the interaction between ground ignition torches and engine components to reduce asymmetrical lateral loads while maintaining external ignition capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The tubular guide is installed on the engine before launch and remains in place during ground ignition. This preliminary positioning ensures that propellants are channeled through a defined path that promotes symmetrical ignition, preventing the development of asymmetrical lateral loads before the engine operates

Inventive Principle:
Principle #10Preliminary action

2Strength

If intrusive ignition torches are used to ignite propellants further upstream, then lateral loads are reduced, but the torches are subjected to high temperature and pressure requiring significant maintenance

Engineering Contradiction:
Improvecomponent strengthVSAvoidmaintenance
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The tubular guide is designed as a disposable component that is inexpensive to manufacture and replace. It is intentionally left in place during ground ignition to provide structural support and propellant channeling, then deliberately destroyed during engine operation when subjected to high temperature and pressure, eliminating the need for maintenance of intrusive ignition components

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Device complexity

If propellants flow in conical shower from neck, then ground ignition is simple, but effective ignition zone is offset from axis of symmetry causing asymmetrical lateral loads

Engineering Contradiction:
Improveignition system complexityVSAvoidcomponent strength
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The tubular guide acts as a mediator that transforms the conical shower flow pattern into a more concentrated, axially-aligned flow. By providing internal walls that confine the propellant flow, the guide mediates between the simple external ignition system and the requirement for symmetrical ignition, reducing asymmetrical lateral loads without increasing overall system complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The tubular guide changes the flow parameters of the propellants by confining them within a defined cylindrical geometry rather than allowing free conical dispersion. This parameter change in flow configuration promotes more uniform distribution around the axis of symmetry, leading to more symmetrical ignition and reduced lateral loads

Inventive Principle:
Principle #35Parameter changes

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 provides safer, more controlled ignition with reduced lateral loads and lower component stresses, enabling lighter rocket engines with reduced maintenance and operational costs by using a tubular guide that is destroyed during operation, thus avoiding performance impact.

Implementation Method 1

a tubular guide, destructible, coaxially attached to the propulsion chamber so as to channel said propellant downstream of the neck of the propulsion chamber

Methodology Applied
Scientific EffectFluid channeling:

Implementation Method 2

at least a part of the guide is configured to withstand at least 2 seconds at a temperature of 1700°C

Methodology Applied
Scientific EffectThermal resistance: Thermal Insulation

Implementation Method 3

the guide circumscribes the ignition zone and can contribute to absorbing part of the detonation energy during ignition, which contributes to reducing the loads undergone by the propulsion chamber

Methodology Applied
Scientific EffectEnergy absorption: Damping

Implementation Method 4

the guide is configured to be destroyed and ejected by the detonation or, at the latest, by the heat and the speed of the flow of burnt gases when the engine starts to operate

Methodology Applied
Scientific EffectDetonation: Detonation

Data Source

PatentEP3426906B1Rocket engine with ground ignition
Publication Date: 2020.04.22 ARIANEGRP SAS
  • EP3426906B1 patent drawingFigure 1~2

AI summary

The invention relates to a rocket engine having more secure and better controlled solar ignition, said rocket engine comprising an axisymmetrical propulsion chamber (12) having a neck (12c) where the diameter of said propulsion chamber (12) is smallest, an injection head (11) designed to inject at least one liquid propellant into the propulsion chamber (12), and a destructible tubular guide (40) arranged coaxially in the propulsion chamber (12) so as to channel said propellant downstream of the neck (12c) of said propulsion chamber (12).