Pulse Detonation Assembly Barriers for Shock Isolation

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Solution Overview

Problem

Optimizing downstream geometry in multi-tube pulse detonation assemblies to reduce undesirable shock interactions between neighboring chambers and minimize flow losses prior to work extraction in hybrid pulse detonation-turbine engines.

Innovation Solution

Incorporating barriers between pulse detonation chambers to define sectors, with high-temperature materials and axial transitions, and using segments to direct detonation product streams, which also mix with bypass flows to reduce hot streaks on turbine components, thereby enhancing the efficiency and longevity of the engine.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If multiple pulse detonation chambers are arranged in a multi-tube assembly, then the thermodynamic efficiency is improved due to lower entropy rise of detonative processes, but undesirable shock interactions between neighboring chambers occur that adversely affect chamber operability

Engineering Contradiction:

Improvethermodynamic efficiencyVSAvoidshock interactions

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent divides the multi-tube pulse detonation assembly into separate sectors using barriers. Each sector contains one or more pulse detonation chambers and is isolated from other sectors by these barriers. This segmentation prevents shock waves from propagating between adjacent chambers, eliminating the harmful shock interactions while maintaining the high thermodynamic efficiency benefits of multiple detonation chambers operating in parallel.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If barriers are introduced between pulse detonation chambers to reduce shock interactions, then shock propagation is reduced, but device complexity increases due to additional structural components

Engineering Contradiction:

Improveshock propagationVSAvoidassembly structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The barriers in the patent serve multiple functions simultaneously: they act as shock reflections to prevent cross-contamination between chambers, provide structural support for the assembly, and can be integrated with the turbine inlet structure. By making the barriers multi-functional, the patent reduces device complexity compared to using separate components for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the transition region geometry from pulse detonation chamber to turbine inlet is not optimized, then manufacturing is simpler, but flow losses increase prior to work extraction by the turbine

Engineering Contradiction:

Improvetransition region geometryVSAvoidflow losses

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent optimizes the transition region geometry by carefully controlling parameters such as the angle of the transition walls, the length of the transition section, and the positioning of the turbine inlet relative to the pulse detonation chambers. These parameter changes reduce flow separation and turbulence, minimizing energy losses while maintaining manufacturability through standard fabrication techniques.

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 effectively reduces shock interactions and flow losses, improving the thermodynamic efficiency and extending the lifespan of turbine components by mixing hot detonation products with cooler bypass air, leading to enhanced performance in hybrid pulse detonation-turbine engines.

Implementation Method 1

the shock may propagate up an adjacent chamber, thereby disturbing the fill cycle of that chamber. This undesirable interaction is particularly relevant for hybrid pulse detonation-turbine applications, where there may be a strong shock reflection from the turbine face.

Methodology Applied

Scientific EffectShock wave reflection: Shock Wave

Implementation Method 2

Pulse detonation engines are a promising propulsion technology, in view of the lower entropy rise of detonative processes, as compared to constant pressure deflagration.

Methodology Applied

Scientific EffectDetonation: Detonation

Implementation Method 3

a common feature incorporates the idea of the exhaust from the multiple pulse detonation chambers driving a downstream turbine

Methodology Applied

Scientific EffectTurbine expansion: Turbine

Implementation Method 4

mix with bypass flows to reduce hot streaks on turbine components

Methodology Applied

Scientific EffectThermal mixing: Convection

Data Source

PatentUS7818956B2Pulse detonation assembly and hybrid engine

Publication Date: 2010.10.26 GENERAL ELECTRIC CO

AI summary

A pulse detonation (PD) assembly includes a number of PD chambers adapted to expel respective detonation product streams and a number of barriers disposed between respective pairs of PD chambers. The barriers define, at least in part, a number of sectors that contain at least one PD chamber. A hybrid engine includes a number of PD chambers and barriers. The hybrid engine further includes a turbine assembly having at least one turbine stage, being in flow communication with the PD chambers and being configured to be at least partially driven by the detonation product streams. A segmented hybrid engine includes a number of PD chambers and segments configured to receive and direct the detonation product streams from respective PD chambers. The segmented hybrid engine further includes a turbine assembly configured to be at least partially driven by the detonation product streams.