Pulsed Combustion Engine with Segmented Detonation
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Solution Overview
Problem
Conventional gas turbine engines operate under continuous, near constant pressure combustion, limiting thermodynamic efficiency, while pulse detonation engines offer more efficient near constant volume combustion, but integrating PDE technology into turbine engines poses challenges in achieving efficient combustion and propulsion.
Innovation Solution
A hybrid turbine engine design featuring a circumferential array of compressor/turbine units and non-rotating combustors, where air is compressed, combusted with fuel, and the combustion gas drives both the compressor/turbine units and fan, with the option for pulse detonation combustion and out-of-phase operation of combustors to minimize pressure pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If continuous near constant pressure combustion is used in conventional gas turbine engines, then the engine structure is simple and reliable, but thermodynamic efficiency is limited
Solution Approach 1:
The combustion system is divided into multiple independent combustors arranged circumferentially around the engine core. Each combustor operates as a separate pulse detonation unit, allowing the system to achieve high thermodynamic efficiency through near constant volume combustion while maintaining modular complexity that is manageable and reliable
Solution Approach 2:
The combustors operate in a pulsed detonation mode rather than continuous combustion. Fuel and oxidizer are admitted periodically, detonated, and the resulting pressure rise drives the turbine. This periodic pulsed action enables near constant volume combustion which significantly improves thermodynamic efficiency compared to continuous constant pressure combustion
2Use of energy by moving object
If pulse detonation combustion is implemented in turbine engines, then thermodynamic efficiency improves, but pressure pulses and potential crosstalk between combustors increase
Solution Approach 1:
Multiple combustors are distributed circumferentially around the engine, separating the combustion events spatially. This segmentation allows each combustor to operate independently with its own fuel injection and detonation timing, preventing pressure wave crosstalk between adjacent combustors while maintaining the efficiency benefits of pulsed detonation
Solution Approach 2:
The combustors are operated out of phase with each other in a periodic sequence. While one combustor is undergoing detonation, others are in different phases of the combustion cycle (fuel injection, ignition, or exhaust). This phased periodic operation smooths out pressure fluctuations and eliminates harmful pressure pulses that would occur if all combustors fired simultaneously
3Volume of moving object
If multiple compressor/turbine units are arranged circumferentially, then compact engine configuration is achieved, but device complexity increases
Solution Approach 1:
Each combustor is uniquely associated with a compressor/turbine unit, merging the combustion function directly with the compression and expansion functions in an integrated manner. The combustion gas from each combustor directly drives its associated turbine, which in turn drives its associated compressor, creating efficient localized energy conversion while maintaining compact circumferential arrangement
Solution Approach 2:
The circumferential array of compressor/turbine units serves multiple functions: compression of incoming air, reception and utilization of combustion gas from associated combustors, and mechanical coupling to drive the fan. This multi-functional arrangement achieves compactness by combining several functions into integrated units rather than separate systems
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
This design enhances thermodynamic efficiency and propulsion by leveraging pulse detonation combustion, achieving efficient energy extraction and compact engine configuration suitable for aircraft propulsion while minimizing observability and crosstalk between combustors.
Implementation Method 1
an igniter is utilized to detonate the charge (either directly or through a deflagration to detonation transition). A detonation wave propagates toward the outlet at supersonic speed causing substantial combustion of the fuel/air mixture
Implementation Method 2
combustion of the fuel/air mixture before the mixture can be substantially driven from the outlet. The result of the combustion is to rapidly elevate pressure within the chamber
Implementation Method 3
Work is extracted from the combustion gas in the turbine to drive rotation of the fan
Implementation Method 4
The air is compressed in the compressor/turbine units. Work is extracted from the combustion gas in the compressor/turbine units to drive the compression
Data Source
AI summary
A turbine engine has a case with an axis. A fan is mounted for rotation about the axis. A turbine is mechanically coupled to the fan to drive rotation of the fan about the axis. A number of compressor/turbine units are downstream of the fan and upstream of the turbine along a core flowpath. A number of compressors are coupled to the compressor/turbine units to receive air and deliver combustion gas to drive the turbine.