Annular Continuous Detonation Ramjet Engine

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Solution Overview

Problem

Pulsed detonation engines generate severe vibratory environments and require significant energy input, especially with fuel-oxidant mixtures that have low detonation characteristics, limiting their performance and efficiency.

Innovation Solution

A ramjet with an annular continuous detonation wave engine design, where fuel and air are injected separately and continuously into the detonation chamber, allowing for self-sustaining detonation waves at high frequencies, reducing fuel consumption, and enhancing thermodynamic efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If pulsed detonation engines are used, then thrust is generated, but severe vibratory environment is created and significant energy input is required

Engineering Contradiction:
Improvethrust generationVSAvoidvibratory environment
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

The patent employs periodic detonation waves that travel continuously through the detonation chamber at high frequencies (50-200 Hz). This periodic action generates thrust pulses that are more regular and less violent compared to conventional pulsed detonation, reducing the harmful vibratory environment while maintaining effective thrust generation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The invention implements continuous injection of fuel and air into the detonation chamber, allowing the detonation wave to propagate continuously rather than in discrete pulses. This continuity of useful action reduces the abrupt start-stop characteristics that cause severe vibrations, while the high-frequency periodic detonation maintains effective thrust output.

Inventive Principle:
Principle #20Continuity of useful action

2Productivity

If pulsed detonation engines operate at high frequency, then thrust frequency increases, but energy input requirement increases significantly

Engineering Contradiction:
Improvethrust frequencyVSAvoidenergy input per cycle
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The detonation chamber is designed to be self-sustaining, where the hot gases from one detonation wave automatically initiate the next detonation wave in the fresh fuel-air mixture. This self-service mechanism eliminates the need for significant external energy input to initiate each detonation cycle, allowing high-frequency operation with reduced energy consumption compared to conventional pulsed detonation engines.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent optimizes parameters such as fuel injection rate, air injection rate, and detonation chamber geometry to enable efficient high-frequency detonation. By adjusting these parameters, the system achieves high thrust frequency while minimizing the energy input required per cycle, as the detonation process becomes more efficient and less energy-intensive at higher frequencies.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If fuel and air are injected separately, then mixing control is improved, but device complexity increases

Engineering Contradiction:
Improvemixing controlVSAvoidinjection system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The injection system is segmented into separate fuel injection means and air injection means, allowing independent control of fuel and air delivery to the detonation chamber. This segmentation enables precise control over the fuel-air mixture ratio and timing, improving mixing control and detonation efficiency while keeping each injection subsystem relatively simple and manageable.

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

The solution achieves a significant increase in combustion efficiency, reduces fuel consumption, and minimizes vibratory stress, enabling higher flight ceilings and improved performance compared to traditional pulsed detonation engines.

Implementation Method 1

the combustion by detonation is carried out very quickly in a very small thickness of the detonating mixture

Methodology Applied
Scientific EffectDetonation: Detonation

Implementation Method 2

combustion by detonation is carried out very quickly

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 3

the hot gases it produces expand into the rest of the detonation chamber

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

to be accelerated by the ejection nozzle to obtain a thrust

Methodology Applied
Scientific EffectThrust generation: Jet

Data Source

PatentEP2525070B1Ramjet engine with detonation chamber and aircraft comprising such a ramjet engine
Publication Date: 2018.02.21 MBDA FRANCE
  • EP2525070B1 patent drawingFigure 1~2
  • EP2525070B1 patent drawingFigure 3~4

AI summary

The engine (S1) has a circular annular detonation chamber (2) i.e. continuous detonation wave chamber, equipped with an air injection bottom (3) at upstream end and terminated by an ejection nozzle (4) at downstream end. An annular air inlet (5) is connected to the detonation chamber to supply air (F1). A fuel injection unit formed of a supply assembly (6) continuously injects fuel (F2) directly into the detonation chamber immediately downstream of the bottom. The injection of fuel and air into the detonation chamber is performed separately in a permanent manner during operation of the engine.