Open Pusher Rotor Remote Exhaust Routing for Thermal Protection
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Solution Overview
Problem
Existing gas turbine engines with open pusher rotor configurations face challenges due to the direct exposure of the rotor to exhaust gases, which affects material durability and performance.
Innovation Solution
The design incorporates an exhaust duct that directs the exhaust flow away from the open pusher rotor system, using a coaxial tube and fairing to isolate the rotor from the exhaust path, and optionally includes a heat exchanger to recover waste heat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the open pusher rotor system is directly exposed to exhaust gases, then the engine structure is simpler, but the material durability and performance of the rotor deteriorates
Solution Approach 1:
The exhaust system is segmented into separate components: the exhaust duct and the rotor drive system are separated spatially. The exhaust duct channels hot gases through a designated path that does not contact the rotor, dividing the engine into distinct thermal zones and protecting the rotor from thermal damage.
Solution Approach 2:
The harmful exhaust flow is extracted from the common path and directed through a separate exhaust duct. This removes the adverse thermal and chemical environment from the rotor's operational space, allowing the rotor to operate in a cooler, cleaner atmosphere while the exhaust follows its own isolated trajectory.
2Reliability
If an exhaust duct is introduced to direct exhaust away from the rotor, then the rotor protection improves, but the device complexity increases
Solution Approach 1:
The exhaust duct is merged with the existing engine structure, utilizing available spaces and mounting points. The duct integrates with the engine housing and mounting pylons, combining multiple structural functions into a single unified assembly rather than adding completely separate components.
Solution Approach 2:
The exhaust duct structure serves multiple functions: it channels exhaust gases away from the rotor, provides structural support for the engine mounting, and can be integrated with the aircraft airframe. This multi-functionality reduces the need for additional dedicated components.
3Reliability
If the exhaust flow is directed away from the rotor, then the rotor durability improves, but the energy recovery opportunity is reduced
Solution Approach 1:
A heat exchanger is introduced as an intermediary device that transfers thermal energy from the exhaust gases to a separate fluid stream without requiring direct contact between the exhaust and the rotor system. This mediator enables energy recovery while maintaining the physical separation needed for rotor protection.
Solution Approach 2:
Thermal energy is extracted from the exhaust flow through the heat exchanger before the exhaust is discharged. This extraction process captures useful heat for auxiliary systems while the remaining exhaust continues its protected path away from the rotor, separating the energy recovery function from the exhaust discharge function.
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 configuration enhances the durability and efficiency of the open pusher rotor by protecting it from exhaust gases while allowing for waste heat recovery, improving the engine's performance and operational reliability.
Implementation Method 1
The exhaust duct extends to an exhaust exit such that a flow path of the exhaust flow leaving the exhaust exit is directed away from the open pusher rotor system
Implementation Method 2
optionally includes a heat exchanger to recover waste heat
Data Source
AI summary
A gas turbine engine includes a compressor section. A combustor is configured to receive compressed air from the compressor section. A turbine section is positioned downstream of the combustor and configured to receive an exhaust flow from the combustor. The turbine section includes a turbine rotor configured to drive a compressor rotor. An open pusher rotor system is mounted downstream of the turbine section, and driven by a propulsor turbine rotor in the turbine section. An exhaust duct is downstream of the propulsor turbine rotor. The exhaust duct extends to an exhaust exit such that a flow path of the exhaust flow leaving the exhaust exit is directed away from the open pusher rotor system. A propulsion system is also disclosed.