Variable Frequency Generator Anti-Icing System
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anti-icing systems for aircraft, whether pneumatic or electrical, often increase the size, weight, and cost of aircraft engines and ductwork, and can impact engine design and efficiency, particularly when relying on high-pressure shafts or bleed air for energy.
Innovation Solution
An electric anti-icing system powered by a variable frequency generator driven by the low-pressure shaft of an aircraft engine, which provides electrical energy to resistive heaters on control surfaces, independent of the pneumatic system and core gas turbine engine, allowing for effective ice prevention without enlarging the engine or increasing its load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a pneumatic anti-icing system uses high-temperature bleed air from the engine, then the anti-icing effectiveness is improved, but the ductwork must be made of specialized high-temperature materials increasing cost and weight
Solution Approach 1:
A variable frequency generator acts as an intermediary device between the engine and the anti-icing system. It converts mechanical energy from the low-pressure shaft into electrical energy, eliminating the need for high-temperature ductwork while maintaining anti-icing effectiveness through electrical heating elements.
Solution Approach 2:
The patent replaces the pneumatic heating system with an electrical heating system. Instead of using hot bleed air that requires specialized ductwork, the system uses electrical resistors heated by a variable frequency generator, thereby eliminating the need for high-temperature material ductwork and reducing weight.
2Ease of manufacture
If a pre-cooler is added to reduce heated air temperature, then the ductwork can be smaller and less expensive, but the pre-cooler size increases the ductwork volume
Solution Approach 1:
The patent eliminates the pre-cooler component entirely by substituting the pneumatic heating system with an electrical heating system. The variable frequency generator provides electrical power to resistive heaters, removing the need for temperature reduction of bleed air and consequently eliminating the pre-cooler and its associated ductwork volume.
3Reliability
If the high-pressure shaft is used to power the anti-icing system, then the anti-icing capability is maintained, but the engine size and weight must be increased
Solution Approach 1:
The patent segments the engine power output by using the low-pressure shaft independently to drive the variable frequency generator. This segmentation allows the high-pressure shaft to maintain its original size and power output for thrust generation, while the low-pressure shaft provides mechanical energy for electrical anti-icing power, avoiding the need to increase engine size.
Solution Approach 2:
The variable frequency generator serves as an intermediary that converts the mechanical energy from the low-pressure shaft into electrical energy. This intermediary device enables the anti-icing system to be powered without directly loading the high-pressure shaft or increasing the core engine size, as the low-pressure shaft has excess capacity that can be utilized.
4Power
If the engine speed is increased to provide more power to the anti-icing system, then the anti-icing effectiveness is improved, but the pilot must increase engine speed which is disadvantageous during descent or holding
Solution Approach 1:
The patent employs a variable frequency generator that can dynamically adjust its electrical output based on the rotational speed of the low-pressure shaft. This dynamic capability allows the anti-icing system to provide sufficient power without requiring the engine to operate at high speeds, as the generator can vary its frequency and voltage output according to the available mechanical energy.
Solution Approach 2:
The variable frequency generator acts as an intermediary between the low-pressure shaft and the anti-icing load. It converts the variable-speed mechanical input into appropriate electrical output, allowing the anti-icing system to receive sufficient power regardless of engine speed, thereby maintaining ease of operation during descent or holding maneuvers.
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 solution enables anti-icing without increasing the size or weight of the aircraft engine, reduces the complexity of ductwork, and maintains engine efficiency by utilizing the low-pressure shaft's energy capacity, thus minimizing the impact on aircraft design and operational stability.
Implementation Method 1
a variable frequency generator driven by a low pressure shaft of an aircraft engine
Implementation Method 2
electrical current flows through the resistors, heat is generated to prevent or reduce the accumulation of ice
Data Source
AI summary
An aircraft, an aircraft engine and a corresponding method provide for anti-icing based upon energy provided by a fan assembly of the aircraft engine, such as by rotation of a low pressure shaft of the fan assembly. The aircraft includes an aircraft body having wings and an aircraft engine carried by the aircraft body. The aircraft engine includes a core gas turbine engine and a fan assembly coupled to the core gas turbine engine. The fan assembly may include a fan, a low pressure turbine and a low pressure shaft connecting the fan and the low pressure turbine. The aircraft engine also includes an electric anti-icing system that has a variable frequency generator driven by the fan assembly, and one or more resistive heaters carried by the wings. The variable frequency generator is configured to provide electrical energy to the one or more resistive heaters.