Aircraft Cabin Environmental Control System with Variable Injection Turbine
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Solution Overview
Problem
Current pneumatic systems for aircraft cabin environmental control face challenges in energy efficiency due to air bleeding from propulsion engines, leading to increased fuel consumption.
Innovation Solution
A system with a mechanically coupled air cycle turbine engine and a second supercharger, utilizing blading with a variable injection cross section to control airflow and recover energy from bled air, along with an intermediate turbocharger to recycle thermal energy, reducing the need for pre-cooling and minimizing air bleeding from propulsion engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If air is bled from the supercharger of the propulsion engine to supply the cabin, then the cabin receives pressurized air, but the energy efficiency of the engine deteriorates and fuel consumption increases
Solution Approach 1:
The patent recovers energy from the bled air by directing it through a turbine that drives a supercharger. The bled air, which would otherwise be wasted, is used to rotate the turbine, and the turbine's mechanical power is used to drive the supercharger that supplies pressurized air to the cabin. This recovers energy that would otherwise be lost and eliminates the need for additional engine power to supply the cabin.
Solution Approach 2:
The patent merges the air supply function with the engine's exhaust system by integrating a turbine-supercharger assembly. The bled air from the supercharger is routed through the turbine, and the turbine is mechanically coupled to the supercharger, creating a combined system where the same air flow serves dual purposes: supplying the cabin and driving the supercharger.
2Ease of operation
If a flow rate control valve is used to control the air supply to the turbine, then the air flow is regulated, but energy losses increase due to the valve's restriction
Solution Approach 1:
The patent replaces the static flow control valve with a dynamic system where the turbine's blade geometry and rotation speed automatically adjust to control air flow. The turbine blades can be pitched or adjusted to vary the flow rate, and the rotational speed of the turbine naturally regulates the air supply to the cabin without requiring restrictive valves.
Solution Approach 2:
The patent replaces the mechanical flow control valve with a pneumatic system where the bled air itself controls the flow through the turbine. The air pressure and flow rate through the turbine are regulated by the turbine's mechanical characteristics rather than by a separate control valve, eliminating the energy losses associated with valve restriction.
3Loss of energy
If the turbine is mechanically coupled to the supercharger, then the supercharger is driven by recovered energy, but the system complexity increases
Solution Approach 1:
The patent makes the turbine-supercharger assembly multi-functional: the turbine serves both as an energy recovery device and as a flow control mechanism, while the supercharger serves both to supply pressurized air to the cabin and to be driven by the turbine. This multi-functionality reduces the need for separate components and simplifies the overall system despite the mechanical coupling.
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 approach limits energy losses and fuel consumption by recovering energy from bled air, allowing for efficient air conditioning with reduced air bleeding from propulsion engines, achieving approximately 15% additional power recovery and maintaining cabin air temperature within 5°C of the desired level.
Implementation Method 1
a turbine (22) which are mechanically coupled together... the turbine comprising an air outlet connected to the cabin by a duct
Implementation Method 2
a first supercharger (21) comprising an air inlet which is connected to said device for bleeding engine air... in order to be able to supply the cabin with air at a controlled pressure and temperature
Implementation Method 3
The system also includes various heat exchangers, control valves and a water extraction loop
Data Source
AI summary
The invention relates to a system for environmental control of an aircraft cabin (5), comprising a device for bleeding compressed air from at least one aircraft engine; an air cycle turbine engine (20) comprising at least one supercharger (21) connected to said device for bleeding compressed air by an air bleed duct (7) and a turbine (22) connected to the cabin (5) by a cabin inlet duct (8) in order to be able to supply said cabin with air at a controlled pressure and temperature, characterised in that it further comprises: stationary blading (23) which has a variable injection cross section and is mounted on said turbine (22) of said air cycle turbine engine (20) so as to be able to modify, on command, the flow rate and/or the pressure of air supplying an air inlet of said turbine (22); and a second supercharger (22) which is mounted on said air cycle turbine engine (20) and is connected to a device for bleeding outside air and to said bleed duct.