Reverse-flow Gas Turbine with Radial Pulse Detonation
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Solution Overview
Problem
Combined gas turbine engines with pulse detonation engines face issues due to excessive heat and vibration, as well as the substantial axial length of firing tubes, which hinder widespread adoption.
Innovation Solution
A reverse-flow core gas turbine engine integrated with a pulse detonation system, where the exhaust gas stream from the low pressure turbine is redirected through a pulse detonation firing tube to mix with fuel, producing a pressure increase and enhanced thrust, while reducing the overall axial length and enhancing cooling of the firing tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional gas turbine engine with co-axial shafts is used, then the engine structure is simpler, but the shafts must be longer and made of stronger materials, increasing weight and manufacturing costs
Solution Approach 1:
The patent inverts the conventional co-axial shaft arrangement by using separate non-coaxial shafts for low pressure and high pressure spools. The low pressure shaft connects the low pressure compressor and turbine, while the high pressure shaft connects the high pressure compressor and turbine, eliminating the need for one shaft to accommodate the other and reducing overall shaft length and weight.
Solution Approach 2:
The patent segments the shaft system into two independent shafts instead of one combined co-axial shaft. This segmentation allows each shaft to be optimized independently for its specific function, reducing the overall weight and complexity of the rotating assembly.
2Power
If pulse detonation engines are integrated with gas turbine engines, then thrust is enhanced, but excessive heat and vibration are generated
Solution Approach 1:
The patent extracts the pulse detonation system from a conventional linear arrangement and positions the firing tubes radially outward from the engine core. This separation isolates the high-heat and high-vibration detonation zones from the sensitive turbine and compressor components, allowing thrust enhancement while protecting the engine core from harmful effects.
Solution Approach 2:
The patent converts the harmful heat and vibration from pulse detonation into beneficial thrust by directing the detonation waves through radially positioned firing tubes that expel exhaust forward. The harmful thermal and mechanical energy is transformed into useful propulsive force while the core engine remains protected.
3Power
If traditional firing tube arrangements are used, then the pulse detonation system functions, but the axial length of the engine increases substantially
Solution Approach 1:
The patent transitions from a conventional axial arrangement of firing tubes to a radial arrangement positioned outward from the engine core. This dimensional change allows the pulse detonation system to function without extending the axial length of the engine, as the firing tubes are now arranged in a radial rather than axial configuration.
4Temperature
If more cooling is provided to the firing tubes, then heat management improves, but the device complexity increases
Solution Approach 1:
The patent makes the bypass air serve multiple functions: it provides thrust by expanding through the bypass duct, and simultaneously cools the radially positioned firing tubes. This multi-functionality eliminates the need for separate dedicated cooling systems, reducing overall device complexity while improving heat management.
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 integration of a pulse detonation system into a reverse-flow core gas turbine engine reduces axial length and improves cooling efficiency, leading to increased thrust and operational effectiveness.
Implementation Method 1
the at least one pulse detonation firing tube is configured to mix the exhaust gas stream with fuel so that the mixed fuel and exhaust gas stream detonates as the mixed fuel and exhaust gas stream pass through the firing tube toward the engine exhaust to thereby produce a pressure increase in the exhaust stream and enhanced thrust from the engine
Implementation Method 2
A reverse-flow core gas turbine engine refers to a gas turbine engine wherein flow of air through the engine is reversed after passing through a low pressure compressor
Data Source
AI summary
The engine (10) includes a low spool (16) disposed aft of an air inlet (12) and a high spool (34) disposed aft of the low spool (16). An intake reverse-duct (44) is disposed radially outward of the high spool (34) and reverses direction of low pressure compressed air from the low spool (16) into a forward-flow high pressure compressor (40) of the high spool (34). A discharge reverse-manifold (48) directs flow of an exhaust gas stream (50} from a forward-flow low pressure turbine (20) into a rearward-flow direction and into at least one pulse detonation firing tube (54). An annular bypass air duct (72) directs cooling air along the engine (10)—The at least, one firing tube is positioned radially outward of the high spool (34), overlies the high spool (34) and is also positioned within the bypass air duct (72).