Piloted Rotating Detonation Engine Shockwave Stability

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Solution Overview

Problem

Rotating detonation engines face stability issues due to increasing gap size in annular channels, which reduces the efficiency and limits the volume of oxidizer and fuel that can pass through, and are dependent on a narrow detonable fuel-oxidizer mixture range.

Innovation Solution

Incorporating an annular pilot chamber with a pilot shockwave that generates a main shockwave in the main chamber, allowing for increased main gap width without stability loss, and extending the detonable limits of the fuel-oxidizer mixture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the gap size of the annular channel is increased to allow more fuel and oxidizer flow, then the volume of substance increases, but the shockwave stability deteriorates

Engineering Contradiction:

Improvevolume of fuel and oxidizerVSAvoidshockwave stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The engine is divided into two separate annular chambers: a pilot chamber for generating and stabilizing the shockwave, and a main chamber for primary combustion. This segmentation allows the pilot chamber to maintain optimal gap dimensions for shockwave stability while the main chamber can accommodate larger dimensions for increased fuel and oxidizer flow capacity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pilot chamber acts as an intermediary that generates a stable pilot shockwave, which then serves to ignite and stabilize the main shockwave in the main chamber. This intermediary mechanism enables the main chamber to operate with larger gap sizes that would otherwise be unstable.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the gap size is increased to improve fuel and oxidizer throughput, then productivity increases, but the shockwave pressure and stability decrease

Engineering Contradiction:

Improvefuel and oxidizer throughputVSAvoidshockwave pressure

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

By segmenting the combustion chamber into pilot and main sections, the system maintains high shockwave pressure in the compact pilot chamber while allowing the main chamber to have larger dimensions for increased throughput, thus resolving the contradiction between pressure maintenance and productivity enhancement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pilot shockwave serves as an intermediary that transfers high pressure and stability from the pilot chamber to the main chamber, enabling the main chamber to achieve high productivity without sacrificing shockwave pressure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the fuel-oxidizer mixture ratio is adjusted to expand operating range, then adaptability improves, but the mixture must remain within narrow detonable limits

Engineering Contradiction:

Improveoperating rangeVSAvoiddetonable mixture stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The fuel-oxidizer mixture delivery is segmented into two independent systems: one for the pilot chamber and one for the main chamber. This allows independent optimization of mixture ratios in each chamber, expanding the overall operating range while maintaining stable detonation in both sections.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The pilot chamber mixture acts as an intermediary that establishes stable detonation conditions, which then enables the main chamber to operate with a broader range of mixture ratios that would otherwise be too lean or rich for stable detonation.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Improves the stability of the main shockwave, enabling increased fuel and oxidizer delivery and expanding the operating range of the engine beyond the limitations of single-chamber designs.

Implementation Method 1

The detonation process includes generating a shockwave, or pressure wave, that is sustained by a chemical combustion process. The shockwave causes an increase in pressure concurrently with the consumption of fuel.

Methodology Applied

Scientific EffectDetonation: Detonation

Implementation Method 2

A rotating detonation engine utilizes shockwaves that move (or travel) circumferentially around an annular channel. The shockwave is capable of continuous propagation around the annular channel with continued provision of fuel.

Methodology Applied

Scientific EffectShock wave: Shock Wave

Data Source

PatentUS11655980B2Piloted rotating detonation engine

Publication Date: 2023.05.23 SOUTHWEST RES INST

AI summary

A rotating detonation engine including an annular main chamber configured to sustain a main shockwave that moves along a perimeter of the main chamber and an annular pilot chamber configured to sustain a pilot shockwave that moves along a perimeter of the pilot chamber. The main shockwave may be generated in response to the pilot shockwave extending into the main chamber.