Rotating Detonation Engine Wave Arrestor for Upstream Pressure Mitigation

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Solution Overview

Problem

Rotating detonation engines generate high-magnitude pressure waves that undesirably propagate upstream, causing potential damage and inefficiency in gas turbine engines and other thrust applications.

Innovation Solution

A wave arrestor is positioned upstream from the detonation location within the rotating detonation engine, featuring a plurality of obstacles, channel splitters, and a main channel with varying cross-sectional areas to reflect and dissipate pressure waves, reducing their magnitude.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If rotating detonation engine operates with detonations, then thrust generation is achieved, but high magnitude pressure waves propagate upstream causing damage and inefficiency

Engineering Contradiction:

Improvethrust generationVSAvoidupstream pressure wave propagation

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The wave arrestor uses the incoming pressure wave's own energy to drive the oscillating diaphragm, which then generates a reflected pressure wave that cancels the incoming wave through destructive interference. The harmful pressure wave is converted into a beneficial counter-wave that eliminates the upstream propagation problem while maintaining thrust generation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The oscillating diaphragm acts as an intermediary element between the detonation source and the upstream flow path. It mediates the pressure wave interaction by oscillating in response to incoming waves and generating reflected waves, thereby protecting the upstream components from direct exposure to high-magnitude pressure waves.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If wave arrestor is positioned upstream from detonation location, then pressure wave magnitude is reduced, but device complexity increases

Engineering Contradiction:

Improvepressure wave magnitudeVSAvoidwave arrestor structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The wave arrestor is designed to be self-regulating through the oscillating diaphragm that automatically responds to incoming pressure waves. The diaphragm oscillates in response to pressure wave magnitude and generates reflected waves without requiring external control systems, sensors, or active components, thereby reducing device complexity while maintaining effectiveness.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The wave arrestor changes the physical parameters of the pressure wave by creating reflected waves with opposite phase and adjusted amplitude. The oscillating diaphragm modifies the pressure wave characteristics (magnitude, phase, direction) to achieve cancellation of upstream propagation while maintaining a relatively simple structural design.

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 wave arrestor effectively reduces the upstream propagation of pressure waves, enhancing engine stability and efficiency by mitigating the adverse effects of detonation-induced pressure waves.

Implementation Method 1

a wave arrestor positioned upstream from a location of detonation and configured to reduce a magnitude of a pressure wave traveling upstream from the location of detonation

Methodology Applied

Scientific EffectPressure wave reflection: Reflection

Implementation Method 2

a first channel splitter configured to split the first main channel into multiple sub-channels such that the pressure wave is split into sub-waves that each propagate through one of the multiple sub-channels

Methodology Applied

Scientific EffectPressure wave dispersion: Dispersion (of waves)

Implementation Method 3

a main channel having a downstream portion and an upstream portion that has a greater cross-sectional area than the downstream portion such that the pressure wave expands in response to reaching the upstream portion, resulting in the magnitude of the pressure wave decreasing

Methodology Applied

Scientific EffectPressure wave expansion: Rarefaction

Data Source

PatentUS10436110B2Rotating detonation engine upstream wave arrestor

Publication Date: 2019.10.08 RTX CORP

AI summary

A rotating detonation engine includes an annulus that defines a volume in which a mixture of an oxidizer and a fuel detonate in a rotating fashion, the volume defining a downstream outlet through which detonation exhaust flows. The rotating detonation engine further includes a wave arrestor positioned upstream from a location of detonation and configured to reduce a magnitude of a pressure wave traveling upstream from the location of detonation.