Rocket Engine Ignition Device Nozzle Insertion

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Solution Overview

Problem

Conventional pyrotechnic igniter systems in spacecraft engines pose safety concerns and generate significant mechanical loads due to pressure inversion during ignition, which can damage the engine structure.

Innovation Solution

An ignition system utilizing a Tesla transformer is inserted into the nozzle of a spacecraft engine, generating electric sparks at the nozzle neck to initiate combustion, with a lightweight mast and base design that minimizes mechanical loads and eliminates the need for mechanical attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pyrotechnic igniters are installed in the combustion chamber, then ignition function is achieved, but safety risks and mechanical loads increase

Engineering Contradiction:

Improveignition reliabilityVSAvoidsafety risks and mechanical loads

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The ignition system is extracted from the combustion chamber and relocated to the nozzle. The igniter assembly is positioned in the divergent section of the nozzle, away from the combustion chamber throat, eliminating the pressure front reversal issue while maintaining ignition functionality through direct exposure to the exhaust flow

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical pyrotechnic ignition system is replaced with an electrical discharge ignition system. High-voltage electrodes generate electric sparks across a gap in the exhaust flow, providing a cleaner, more controllable ignition method that reduces mechanical stress on the engine structure

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If ground ignition is used with downstream location, then ignition is achieved, but pressure front reversal causes structural loads

Engineering Contradiction:

Improveignition capabilityVSAvoidmechanical loads on engine structure

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

Instead of igniting from the combustion chamber throat moving downstream, the ignition is inverted to occur downstream in the nozzle and the flame propagates upstream into the combustion chamber. This reverses the pressure front direction, preventing load reversal on the engine structure

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The nozzle exhaust flow serves as an intermediary medium for ignition. The electric spark is generated in the exhaust flow rather than directly in the combustion chamber, using the exhaust as a buffer zone that prevents direct pressure shock waves from impacting the combustion chamber structure

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If pyrotechnic igniters are placed in combustion chamber, then ignition is achieved, but complex safety procedures are required

Engineering Contradiction:

Improveignition functionVSAvoidsafety procedures complexity

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The pyrotechnic chemical ignition system is replaced with an electrical discharge system. The electrical ignition system eliminates the need for handling pyrotechnic materials, reducing safety procedure complexity while maintaining reliable ignition through controllable high-voltage sparks

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The igniter assembly is designed as a disposable component that is installed in the nozzle for a single ignition event and then discarded. This eliminates the need for complex safety procedures for igniter handling, storage, and disposal that would be required for reusable pyrotechnic systems

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 Tesla transformer-based ignition system reduces safety risks and mechanical loads, offering a cost-effective, single-use solution for spacecraft engine ignition with reduced structural damage and simplified safety procedures.

Implementation Method 1

an electrical spark generation circuit configured to generate sparks in the nozzle, so as to cause ignition of the combustion chamber

Methodology Applied

Scientific EffectElectrical discharge: Electric Spark

Implementation Method 2

The electrical circuit for generating sparks is, for example, a Tesla transformer

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3555452B1Ignition device of a rocket engine

Publication Date: 2020.09.02 ARIANEGRP SAS

Figure 1~2
Figure 3

AI summary

The invention relates to an ignition system (2) for a spacecraft engine comprising a combustion chamber (11) and a nozzle (1); the ignition system (2) being designed to be inserted into the nozzle (1) and comprising an electric spark-generating circuit designed so as to generate sparks in the nozzle (1) in such a way as to cause ignition of the combustion chamber (11).