Final Report Summary - HETEMS (Hybrid WIPS Design code)
Executive Summary:
The modular Hybrid ElectroThermal and ElectroMechancial Simulation (HETEMS) software is a new capability to design modern low power electrical wing ice protection systems (WIPS). The five year project (no. 255657, HETEMS) included development, verification and validation of the various simulation models combined with a large scale test in the CIRA Icing Wind Tunnel, in December 2013, to provide data for code validation. The sole beneficiary of the project was AeroTex UK LLP, although the project required and used input from several key collaborative members and the Topic Manager. Both traditional electrothermal (ET) and new electromechanical (EM) IPS, or combinations of both (known as Hybrid systems, or HIPS) may be simulated in the code using either fast and efficient 2D methods, or more detailed, but longer to conduct, analyses using 3D methods. Comparisons with test data from predicted model temperature and ice shed show an acceptable level of correlation. All of the industrial partners have been given a licence to use the HETEMS software for use in their own, in-house, IPS design. AeroTex plan to continue to extend the capability in the future to model rotating components, such as engine fan blades or propellers (under the FP7 STORM project). At AeroTex, the HETEMS modules are already finding application in support of customer projects, both for R&D and aircraft specific programmes in support of icing certification activities.
Project Context and Objectives:
Until now, there was no known fully integrated software suite which allowed the concurrent analysis of both electrothermal (ET) and electromechanical (EM) ice protections systems (IPS). Indeed, there are only a very small number of three-dimensional computer simulation tools in existence world-wide for the assessment of wing leading edges under 'classical' in-flight icing conditions (as specified in EASA CS-25 Appendix C). Only a few of these have even a basic capability to model ET systems, and even fewer are available for commercial licence.
ET systems have been in use for many years, particularly on rotorcraft, and have now found use on wing leading edges (Boeing 787). Their major advantage is the ability to maintain an ice-free surface (when operated in anti-ice mode). However, their high power requirement (150-200kW for a typical 250-seat jet transport aircraft) is very restrictive for wider application. EM Wing Ice Protection Systems (WIPS) are favoured for their low electrical power requirement, but can only operate in a de-ice mode, and residual ice can be severely detrimental to the wing aerodynamics. To date, EM systems have only been certified for use on an aircraft horizontal stabiliser. More recently, the idea of hybrid ET and EM systems has been promoted, with the ET part being used on the leading edge, where the aerodynamics are most critical, and EM further aft to save electrical power. ET simulation tools are commercially available, for 2D applications, and are widely used in industry for design and development. Finite-element (FE) tools can be used to aid the design of EM systems, although the complex interaction at the ice/surface interface, where the adhesive and cohesive strength is dependent on temperature, the surface roughness and material type, is a significant area of difficulty. In order for hybrid systems to be developed to a stage where they can be routinely applied in place of the current systems (bleed-air or sole ET systems), the correct simulation tools must be available. These must take account of the 3D nature of the problem (particularly on the EM side, where local deformations are transferred across the structure), and also the highly different time-scales involved between an ET system (operating at elevated temperature over several seconds, if not minutes) and an EM system, which provides high-energy input over a number of milliseconds. Such a tool was developed in this project. The modular Hybrid ElectroThermal and ElectroMechancial Simulation (HETEMS) design tool will provide a step change in the ability to model hybrid ice protection systems, which are an important part of the development of Green Systems for aircraft. The modular aspect of the code will also in the future allow the issue of shed ice trajectories to be addressed, which is currently an area only dealt with by specific, and entirely separate analysis methods.
Some of the available tools for ice accretion and protection simulation have been developed from an academic perspective, where the correct answer is the driving force behind the development. In practical engineering applications, there is also an analysis time constraint. The nature of some of the current 3D tools means that analysis time is too long for realistic development of a system, where a large number of design iterations may be required. A major focus in the development of this tool was therefore to use simulation methods which minimise the computational time, leading to a tool which can be applied early in the system development stage, and which will reduce overall development time, and hopefully lead to a reduction in the, highly costly, experimental test stage. The main project objective is therefore to develop and validate (using high-quality data also gathered under this project) a simulation tool which not only meets all of the requirements in the original CfP, but one which can be applied in practical use within the Aerospace Industry to push forwards the technical capability of ice protection systems, specifically geared towards improvement in power consumption without compromising system operation. In this respect, the HETEMS modules include both fast two-dimensional (2D) solvers as well as three-dimensional (3D) solvers for final detailed design. The latter modules still require substantial computing efforts (can be several days). The former are very fast to run, and enable design iterations to be completed within a matter of a few minutes. Both tool suites are therefore needed for practical WIPS design.
Project Results:
The main results are twofold;
1) A highly modern, advanced, aircraft icing analysis tool (HETEMS) for the design of electrothermal, ET, electromechancial, EM, or combined ET-EM wing ice protection systems, offering prospects of developing and certifying low power systems in the future. HETEMS is a series of modules both 2D and 3D for aerodynamics, cloud droplet catch efficiency, ice accretion analysis and ice protection system design.
2) A high quality database of test data obtained in the CIRA icing wind tunnel, consisting of ice and ice protection system performance on a full scale, wing tip section, of a business jet aircraft. The data base was used to validate the HETEMS simulation tool.
Potential Impact:
The members involved in HETEMS now have the capability for a comprehensive analysis of icing conditions and for the design of modern ice protection systems. Emerging, low power, Electromechanical ice protection systems can be simulated, and also in combination with more traditional, but usually higher power, Electrothermal systems, or in combination (Hybrid systems). Many of the members have already used HETEMS modules in their in-house projects. This is especially true of AeroTex, who routinely use the modules and experience gained under this project to support our commercial customers.
The aims of the project were presented at the 2011 SAE International Icing Conference held in Chicago, June 2011. This year, the results of the project are to be presented at the 2015 SAE International Icing Conference to be held in Prague, June 2015.
The successful completion of the CIRA icing wind tunnel test, in December 2013, of a full scale wing tip, containing both traditional ET IPS outboard, and a first generation Hybrid IPS inboard, was disseminated as a Clean Sky news item. Links are given below
Clean Sky:
http://www.cleansky.eu/content/interview/clean-sky-sgo-itd-hybrid-ice-protection-system-tests-iwt-completed-successfully
CIRA website:
http://www.cira.it/en/comunicazione-en/news/terminati-con-successo-i-test-su-sistema-201cibrido201d-di-protezione-dal-ghiaccio
The main external exploitation route is a free, 5-year, licence given to each the supporting members.
List of Websites:
http://www.aerotex.co.uk/HETEMS/HETEMS.htm
Email: contact@aerotex.co.uk
Office Suite 2E
Westmead House
Westmead
Farnborough
Hampshire
GU14 7LP, UK
Tel: +44 (0)1252 540693
Fax: +44 (0)1252 548535
The modular Hybrid ElectroThermal and ElectroMechancial Simulation (HETEMS) software is a new capability to design modern low power electrical wing ice protection systems (WIPS). The five year project (no. 255657, HETEMS) included development, verification and validation of the various simulation models combined with a large scale test in the CIRA Icing Wind Tunnel, in December 2013, to provide data for code validation. The sole beneficiary of the project was AeroTex UK LLP, although the project required and used input from several key collaborative members and the Topic Manager. Both traditional electrothermal (ET) and new electromechanical (EM) IPS, or combinations of both (known as Hybrid systems, or HIPS) may be simulated in the code using either fast and efficient 2D methods, or more detailed, but longer to conduct, analyses using 3D methods. Comparisons with test data from predicted model temperature and ice shed show an acceptable level of correlation. All of the industrial partners have been given a licence to use the HETEMS software for use in their own, in-house, IPS design. AeroTex plan to continue to extend the capability in the future to model rotating components, such as engine fan blades or propellers (under the FP7 STORM project). At AeroTex, the HETEMS modules are already finding application in support of customer projects, both for R&D and aircraft specific programmes in support of icing certification activities.
Project Context and Objectives:
Until now, there was no known fully integrated software suite which allowed the concurrent analysis of both electrothermal (ET) and electromechanical (EM) ice protections systems (IPS). Indeed, there are only a very small number of three-dimensional computer simulation tools in existence world-wide for the assessment of wing leading edges under 'classical' in-flight icing conditions (as specified in EASA CS-25 Appendix C). Only a few of these have even a basic capability to model ET systems, and even fewer are available for commercial licence.
ET systems have been in use for many years, particularly on rotorcraft, and have now found use on wing leading edges (Boeing 787). Their major advantage is the ability to maintain an ice-free surface (when operated in anti-ice mode). However, their high power requirement (150-200kW for a typical 250-seat jet transport aircraft) is very restrictive for wider application. EM Wing Ice Protection Systems (WIPS) are favoured for their low electrical power requirement, but can only operate in a de-ice mode, and residual ice can be severely detrimental to the wing aerodynamics. To date, EM systems have only been certified for use on an aircraft horizontal stabiliser. More recently, the idea of hybrid ET and EM systems has been promoted, with the ET part being used on the leading edge, where the aerodynamics are most critical, and EM further aft to save electrical power. ET simulation tools are commercially available, for 2D applications, and are widely used in industry for design and development. Finite-element (FE) tools can be used to aid the design of EM systems, although the complex interaction at the ice/surface interface, where the adhesive and cohesive strength is dependent on temperature, the surface roughness and material type, is a significant area of difficulty. In order for hybrid systems to be developed to a stage where they can be routinely applied in place of the current systems (bleed-air or sole ET systems), the correct simulation tools must be available. These must take account of the 3D nature of the problem (particularly on the EM side, where local deformations are transferred across the structure), and also the highly different time-scales involved between an ET system (operating at elevated temperature over several seconds, if not minutes) and an EM system, which provides high-energy input over a number of milliseconds. Such a tool was developed in this project. The modular Hybrid ElectroThermal and ElectroMechancial Simulation (HETEMS) design tool will provide a step change in the ability to model hybrid ice protection systems, which are an important part of the development of Green Systems for aircraft. The modular aspect of the code will also in the future allow the issue of shed ice trajectories to be addressed, which is currently an area only dealt with by specific, and entirely separate analysis methods.
Some of the available tools for ice accretion and protection simulation have been developed from an academic perspective, where the correct answer is the driving force behind the development. In practical engineering applications, there is also an analysis time constraint. The nature of some of the current 3D tools means that analysis time is too long for realistic development of a system, where a large number of design iterations may be required. A major focus in the development of this tool was therefore to use simulation methods which minimise the computational time, leading to a tool which can be applied early in the system development stage, and which will reduce overall development time, and hopefully lead to a reduction in the, highly costly, experimental test stage. The main project objective is therefore to develop and validate (using high-quality data also gathered under this project) a simulation tool which not only meets all of the requirements in the original CfP, but one which can be applied in practical use within the Aerospace Industry to push forwards the technical capability of ice protection systems, specifically geared towards improvement in power consumption without compromising system operation. In this respect, the HETEMS modules include both fast two-dimensional (2D) solvers as well as three-dimensional (3D) solvers for final detailed design. The latter modules still require substantial computing efforts (can be several days). The former are very fast to run, and enable design iterations to be completed within a matter of a few minutes. Both tool suites are therefore needed for practical WIPS design.
Project Results:
The main results are twofold;
1) A highly modern, advanced, aircraft icing analysis tool (HETEMS) for the design of electrothermal, ET, electromechancial, EM, or combined ET-EM wing ice protection systems, offering prospects of developing and certifying low power systems in the future. HETEMS is a series of modules both 2D and 3D for aerodynamics, cloud droplet catch efficiency, ice accretion analysis and ice protection system design.
2) A high quality database of test data obtained in the CIRA icing wind tunnel, consisting of ice and ice protection system performance on a full scale, wing tip section, of a business jet aircraft. The data base was used to validate the HETEMS simulation tool.
Potential Impact:
The members involved in HETEMS now have the capability for a comprehensive analysis of icing conditions and for the design of modern ice protection systems. Emerging, low power, Electromechanical ice protection systems can be simulated, and also in combination with more traditional, but usually higher power, Electrothermal systems, or in combination (Hybrid systems). Many of the members have already used HETEMS modules in their in-house projects. This is especially true of AeroTex, who routinely use the modules and experience gained under this project to support our commercial customers.
The aims of the project were presented at the 2011 SAE International Icing Conference held in Chicago, June 2011. This year, the results of the project are to be presented at the 2015 SAE International Icing Conference to be held in Prague, June 2015.
The successful completion of the CIRA icing wind tunnel test, in December 2013, of a full scale wing tip, containing both traditional ET IPS outboard, and a first generation Hybrid IPS inboard, was disseminated as a Clean Sky news item. Links are given below
Clean Sky:
http://www.cleansky.eu/content/interview/clean-sky-sgo-itd-hybrid-ice-protection-system-tests-iwt-completed-successfully
CIRA website:
http://www.cira.it/en/comunicazione-en/news/terminati-con-successo-i-test-su-sistema-201cibrido201d-di-protezione-dal-ghiaccio
The main external exploitation route is a free, 5-year, licence given to each the supporting members.
List of Websites:
http://www.aerotex.co.uk/HETEMS/HETEMS.htm
Email: contact@aerotex.co.uk
Office Suite 2E
Westmead House
Westmead
Farnborough
Hampshire
GU14 7LP, UK
Tel: +44 (0)1252 540693
Fax: +44 (0)1252 548535