Angle of Attack Sensor Airfoil with Convex Anti-Icing Profile

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Solution Overview

Problem

Angle of attack sensors with rotatable vanes face accuracy degradation due to hindrance in free rotation and aerodynamic interference caused by icing conditions, which requires significant electrical power for heating elements to prevent ice accumulation.

Innovation Solution

The design incorporates a vane with a nonlinear and geometrically convex outer surface profile, allowing for smaller and more power-efficient heating elements by reducing heat transfer and liquid water collection, enabling effective anti-icing and deicing operations with reduced electrical current and physical size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by stationary object

If conventional flat or linear surface vanes are used, then the vane structure is simple and easy to manufacture, but the heating elements require significant electrical power and larger physical size to prevent ice accumulation

Engineering Contradiction:

Improveelectrical power consumption of heating elementsVSAvoidairfoil surface profile complexity

Core Design Contradiction:

Use of energy by stationary objectVSDevice complexity

Solution Approach 1:

The airfoil is designed with a nonlinear and geometrically convex outer surface profile that is curved rather than flat or linear. This curvature reduces the surface area exposed to oncoming airflow, thereby reducing heat transfer and liquid water collection, which allows for smaller and more power-efficient heating elements while maintaining anti-icing effectiveness

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the airfoil surface from conventional flat or linear profiles to a specifically designed nonlinear convex profile. This parameter change optimizes the balance between aerodynamic performance, ice accumulation reduction, and heating element efficiency, resolving the contradiction between energy consumption and device complexity

Inventive Principle:

Principle #35Parameter changes

2Reliability

If larger heating elements are used to prevent ice accumulation, then anti-icing effectiveness is improved, but the electrical current required increases significantly

Engineering Contradiction:

Improveanti-icing effectivenessVSAvoidelectrical current consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The curved convex surface of the airfoil reduces the amount of liquid water that can accumulate on the vane by minimizing the surface area exposed to oncoming airflow. This geometric modification reduces the heating requirement, allowing for smaller heating elements that consume less electrical current while maintaining reliable anti-icing protection

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention converts the potentially harmful effect of the convex surface (reduced heat transfer) into a benefit by minimizing ice accumulation. The reduced heat transfer to the airflow directly translates to reduced heat loss, which decreases the electrical current needed for heating elements to maintain anti-icing effectiveness

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If heating elements are positioned farther from the leading edge, then manufacturing is easier, but anti-icing effectiveness is reduced due to increased heat transfer and liquid water collection

Engineering Contradiction:

Improveheating element positioningVSAvoidice accumulation on vane

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The convex curved surface profile naturally directs airflow and reduces liquid water collection along the entire length of the airfoil. This geometric feature allows heating elements to be positioned optimally for both manufacturing ease and anti-icing effectiveness, as the curved surface minimizes ice accumulation regardless of the exact heating element position

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 decreases the physical size and electrical current required by heating elements, enhancing the accuracy and efficiency of angle of attack determination while minimizing power consumption.

Implementation Method 1

a heating element disposed within the airfoil between the first and second lateral faces

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

Aerodynamic forces acting on the rotatable vane cause the vane to align with the direction of the oncoming airflow

Methodology Applied

Scientific EffectAerodynamic force: Drag

Data Source

PatentUS10725065B2Angle of attack sensor with rotatable airfoil

Publication Date: 2020.07.28 ROSEMOUNT AEROSPACE INC

AI summary

An angle of attack sensor includes a vane that is freely rotatable to align with a direction of an oncoming airflow over the vane. The airfoil includes a root proximate a vane hub that connects to a rotatable shaft, a tip opposite the root, a leading edge, a trailing edge opposite the leading edge, a first lateral face, a second lateral face, and a heating element disposed within the airfoil between the first and second lateral faces proximate the leading edge. The first lateral face extends from the leading edge to the trailing edge. The second lateral face is opposite the first lateral face and extends from the leading edge to the trailing edge. The first and second lateral faces are symmetric about a chord of the airfoil and each have an outer surface profile that is nonlinear and geometrically convex from the leading edge to the trailing edge.