Aircraft Icing

Introduction

AeroTex UK offers a consultancy service in the field of Aircraft Icing. We have a high level of experience in this area, with specific knowledge relating to:

• Electrothermal ice protection systems
• Electromechanical ice protection systems
• Hot-air ice protection systems
• Icing wind tunnel testing
• Natural icing flight testing
• Certification of ice protection systems
• Icing instrumentation

Analysis Codes

AID (Aircraft Icing Design)

AID is a suite of tools designed to provide a complete solution for aircraft icing analysis. It has been designed using a modular approach to provide maximum flexibility.

2D Components

TAC2

Trajectory and Catch, for the prediction of water droplet trajectories and the resulting surface water collection efficiency on multi-element aerofoils (2D calculation)

IHB

Icing Heat Balance, for the calculation of ice growth rates on the surface, and hence the resulting ice shape. Can also be used for the initial sizing of heating power requirements for anti-ice systems (2D calculation)

HAC

Hot-Air Code, for the predicton of thermal and icing response to a pneumatic (bleed- air) ice protection system (2D calculation). This module is undergoing final development.

3D Components

ET3D

Electrothermal 3D, for the prediction of thermal transients and icing response in a multi-layered structure with embedded heater elements (1D, 2D or 3D)

IDP

Ice Detector Placement, for the prediction of droplet trajectories and resulting cloud concentration coefficient, which are important when siting ice detectors on an aircraft fuselage

The code modules are designed to be able to be run separately, but are also able to be fully integrated so that they form a complete solution suite. If required, additional subroutines can be provided to allow any of the modules to interact with other software (e.g. interaction with a Simulink process to model a complete control system).

DRT (Droplet Residence Time)

DRT is an analysis code to determine the residence time for droplets in an icing wind tunnel. The residence time is defined as the time (and hence distance) for a slow moving water droplet, injected into a fast moving air-stream, to achieve velocity and thermal equilibrium with its surroundings. This is important, since if they are not in equilibrium they will not act in the same way as they do in nature when they impact a surface.

The code is designed to be used to provide advice on the ability of an icing wind tunnel facility to accurately simulate Super-cooled Large Droplets (SLD) icing conditions, although it is also applicable to ‘classical’ icing conditions. The larger the droplets, the longer it takes them to reach equilibrium. Therefore, a tunnel which is well-suited to re-producing classical icing conditions may not be able to accurately reproduce the effects of SLD conditions, even if it is capable of producing droplets of the required size.

HETEMS (Hybrid Electrothermal-Electromechanical Simulation)

The HETEMS programme is funded as part of the European Union (EU) ‘Clean Sky’ Joint Technology Initiative (JTI). The HETEMS project forms part of the System for Green Operations Integrated Technology Demonstrator (SGO-ITD) which is seeking to improve aircraft operation through management of energy and mission trajectory. The demand for this work and the use of Hybrid ElectroThermal-ElectroMechanical systems is driven by a desire to reduce power usage by Ice Protection Systems (IPS). In addition there is an increasing desire to use simulation over extensive testing to design IPS.