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Numerical simulation of a hot-air anti-icing system
Abstract
The paper presents results of the numerical simulation of a hot-air anti-icing system model. A 2D Navier-Stokes CFD code is used to simulate jet impingement on (a) a flat plate and (b) the inner surface a slat of a multi-element airfoil, a modijied RAE 2822 airfoil. The flat plate case is ·used to validate numerical predictions by comparison with known empirical correlations. Since these correlations are being used in most of the anti-icing simulation codes, the slat case is used to determine their applicability to concave surfaces. The results indicate that the empirical correlations are not reliable enouqh for use in anti-icing simulaions. The CFD code is then coupled to an ice accretion and anti-icing
simulation code, CANICE. The overall computational procedure is presented with the help of an example. The
merits of using the CFD tooL in conjunction with the CANICE code are discussed.
... In fact, when the anti-icing protection is on, the airfoil and therefore its aerodynamic properties remain undisturbed. However, the power required to achieve the anti-icing of all the protected area simultaneously has a significant cost [145]. According to studies, the specific power required to achieve ice protection using such system would be up to 420 kW for an Airbus A320 which corresponds to 25 kW/m² [38]. ...
The accumulation of ice on aircraft has been a well-identified issue since the early 1900s. The solutions currently used in flight (blowing hot air from engines, electro-thermal heating mats, inflatable pneumatic boots, deformable electromagnetic coils) provide effective protection but require significant power, maintenance or bulky power supply. Moreover, in the scope of more electric aircraft, thermal engine dependant systems are most likely to become obsolete therefore opening the way for new electric systems. Electro-mechanical ice protection systems have recently proved to be relevant in term of power consumption and embedded mass and are the subject of this thesis.The thesis focuses on the design of resonant electro-mechanical de-icing systems based on novel structures or actuators architectures. The electromechanical resonant de-icing system studied is based on piezoelectric actuators. Being supplied by alternative currents, the piezoelectric ceramics vibrate exciting the structure at a given frequency. When matching with the structure natural frequencies, the vibrations magnitude increases thanks to the resonance phenomenon, generating high levels of stresses and strain, eventually exceeding the critical strength or toughness of the ice. The objective of this thesis is to develop a prototype that could demonstrate an effective ice protection with low peak power consumption (under 10 kW/m²) and rapid de-icing.In order to design an effective and efficient electro-mechanical resonant de-icing system, many topics were investigated and are developed in this thesis manuscript.Based on fracture mechanics theory, the mechanical shedding mechanisms of the ice are first studied. Prelaminar studies are carried out on plates samples to facilitate the computations and experiments. Using finite element modal analysis and fracture analysis tools, the various ice fracture mechanisms are identified and the triggering conditions assessed. The theoretical mechanisms assumed are confirmed by experimental verifications.This knowledge of ice fracture mechanisms has been leveraged to conduct a hybrid numerical/experimental campaign to accurately measure the mechanical properties of the atmospheric ice which are used to assess the performance of electro-mechanical ice protection systems.Then, key performance indicators (KPI) based on energy, power, stress and energy release rate are proposed and used to design electro-mechanical resonant de-icing systems. They are incorporated in an optimization tool allowing reshaping the substrate to maximize the de-icing efficiency. The ice protection systems efficiency is also improved by the synthesis of a control law which allows the tracking of the resonant modes and minimizes the de-icing time.More realistic applications are also investigated. Using criteria, ice properties and fracture mechanism knowledge acquired thanks to prelaminar studies, an electro-mechanical resonant de-icing system has been designed for a NACA prototype and assessed in an icing wind tunnel.Finally, in the last section of the PhD, based on the performance of the prototype developed during the thesis, electro-mechanical resonant ice protection systems are assessed by quantifying the power requirement, the drag penalty and the additional mass of the system and its dedicated sub systems. This approach enables to highlight the benefits at the fleet level of the electro-mechanical resonant solutions.
... Par exemple, les solutions thermiques nécessitent l'évaluation des besoins en puissance thermique [14,323]. Les systèmes thermopneumatiques sont spécifiquement étudiés dans [15,270]. Quant aux systèmes électrothermiques, des modèles sont par exemple détaillés dans [208]. ...
Le transport aérien est à ce jour responsable de 2 à 3 % des émissions mondiales de CO2, ainsi que d'autres impacts climatiques et environnementaux. Les nouveaux concepts d'architectures pouvant contribuer à la réduction de l’impact environnemental de l'aviation suscitent donc un grand intérêt. L’objectif de cette thèse est de contribuer au développement d’une approche holistique, allant de la modélisation et du dimensionnement de nouvelles architectures avion à la simulation de scénarios prospectifs durables pour le transport aérien. Cette approche permet ainsi de relier les enjeux de la conception avion à ceux de l’analyse de scénarios prospectifs pour l’aviation. Dans une première partie, des modèles d'estimation pour différents systèmes avion sont présentés dans le cadre d’un avion plus électrique. Des méthodes variées sont appliquées, par exemple basées sur l’utilisation de modèles énergétiques ou de modèles de régression. Les systèmes de conditionnement d’air et de protection contre le givre sont étudiés, tout comme les systèmes induits par l’électrification des avions (génération et distribution de puissance électrique, management thermique). Dans une deuxième partie, une architecture avion déployable à court terme est dimensionnée à travers une approche basée sur l’utilisation de la plateforme de conception avion FAST-OAD. Cette architecture intègre les systèmes décrits précédemment, dont les performances sont préalablement évaluées individuellement via des modèles spécifiques, ainsi que des améliorations propulsives et aéro-structurelles. Les caractéristiques de l'architecture complète sont alors analysées, notamment concernant ses impacts environnementaux à partir d'un module d'analyse de cycle de vie développé pour FAST-OAD.Dans une dernière partie, l'outil CAST développé dans cette thèse est présenté. Il permet de simuler et d'évaluer des scénarios prospectifs pour le transport aérien. Des modèles sont détaillés pour les différents leviers d’action permettant de réduire l'impact environnemental du transport aérien. Une attention particulière est portée sur l’introduction d’architectures plus efficaces dans la flotte. Pour évaluer la durabilité des scénarios, des méthodologies spécifiques sont proposées pour les enjeux climatiques et énergétiques, en s'appuyant par exemple sur la notion de budget carbone. Plusieurs applications montrent alors le bénéfice des nouvelles technologies mais aussi le besoin d’un arbitrage entre le niveau de trafic aérien et la part du budget carbone mondial allouée au secteur aérien.
... In fact, when the anti-icing protection is on, the airfoil and therefore its aerodynamic properties remain undisturbed. However, the power required to achieve the anti-icing of all the protected area simultaneously has a significant cost [145]. According to studies, the specific power required to achieve ice protection using such system would be up to 420 kW for an Airbus A320 which corresponds to 25 kW/m² [38]. ...
The accumulation of ice on aircraft has been a well-identified issue since the early 1900s. The solutions currently used in flight (blowing hot air from engines, electro-thermal heating mats, inflatable pneumatic boots, deformable electromagnetic coils) provide effective protection but require significant power, maintenance or bulky power supply. Moreover, in the scope of more electric aircraft, thermal engine dependant systems are most likely to become obsolete therefore opening the way for new electric systems. Electro-mechanical ice protection systems have recently proved to be relevant in term of power consumption and embedded mass and are the subject of this thesis.The thesis focuses on the design of resonant electro-mechanical de-icing systems based on novel structures or actuators architectures. The electromechanical resonant de-icing system studied is based on piezoelectric actuators. Being supplied by alternative currents, the piezoelectric ceramics vibrate exciting the structure at a given frequency. When matching with the structure natural frequencies, the vibrations magnitude increases thanks to the resonance phenomenon, generating high levels of stresses and strain, eventually exceeding the critical strength or toughness of the ice. The objective of this thesis is to develop a prototype that could demonstrate an effective ice protection with low peak power consumption (under 10 kW/m²) and rapid de-icing.In order to design an effective and efficient electro-mechanical resonant de-icing system, many topics were investigated and are developed in this thesis manuscript.Based on fracture mechanics theory, the mechanical shedding mechanisms of the ice are first studied. Prelaminar studies are carried out on plates samples to facilitate the computations and experiments. Using finite element modal analysis and fracture analysis tools, the various ice fracture mechanisms are identified and the triggering conditions assessed. The theoretical mechanisms assumed are confirmed by experimental verifications.This knowledge of ice fracture mechanisms has been leveraged to conduct a hybrid numerical/experimental campaign to accurately measure the mechanical properties of the atmospheric ice which are used to assess the performance of electro-mechanical ice protection systems.Then, key performance indicators (KPI) based on energy, power, stress and energy release rate are proposed and used to design electro-mechanical resonant de-icing systems. They are incorporated in an optimization tool allowing reshaping the substrate to maximize the de-icing efficiency. The ice protection systems efficiency is also improved by the synthesis of a control law which allows the tracking of the resonant modes and minimizes the de-icing time.More realistic applications are also investigated. Using criteria, ice properties and fracture mechanism knowledge acquired thanks to prelaminar studies, an electro-mechanical resonant de-icing system has been designed for a NACA prototype and assessed in an icing wind tunnel.Finally, in the last section of the PhD, based on the performance of the prototype developed during the thesis, electro-mechanical resonant ice protection systems are assessed by quantifying the power requirement, the drag penalty and the additional mass of the system and its dedicated sub systems. This approach enables to highlight the benefits at the fleet level of the electro-mechanical resonant solutions.
... Two-dimensional heat transfer via hot-jet impingement on a flat plate and the inner leading-edge surface of a modified RAE 2822 airfoil was simulated by Saeed et al. 39 using the commercial CFD software ANSYS Fluent. Numerical simulation of a pair of slot jets impinging on an inclined surface was performed by Patel and Roy 35 to study the effect of jet angle and Reynolds number on the local and average Nusselt. ...
Many approaches exist today that employ hot-air from aircraft compressor bleed for anti-icing critical aircraft surfaces. This paper introduces and numerically analyzes the novel application of an inner or etched channel to augment heat transfer from a hot-air jet impinging on a curved surface representing the inner surface of an aircraft wing's leading edge or slat. The study shows that proper positioning, geometry, and flow characteristics of a channel along the inner surface of the leading edge can significantly enhance heat transfer, boost the anti-icing system performance, and greatly enhance flight safety during critical icing weather conditions. Commercially available CFD software, ANSYS Fluent is used to model and analyze the effect of different geometric and flow parameters typical of those found in small to medium category commercial transport aircraft to help determine the optimum arrangement. These parameters include: (1) jet nozzle height-to-slot diameter ratios from 4 to 8, (2) channel width-to-slot diameter ratios from 0.4 to 1.8, and (3) inner-channel inlet location angles from 10°to 60°. Each configuration resulting from a combination of the above parameters was simulated at Reynolds numbers based on jet-slot diameter of 30,000, 60,000, and 90,000. Empirical relations based on available experimental data are used to validate the results. The main findings of the study reveal that the jet height-to-slot diameter ratio of 6, inner channel height-to-slot diameter ratios of 1.8, and inner-channel inlet angular locations of 10°combination resulted in the highest heat transfer at all Reynolds number as well as higher at increased Reynold numbers.
A novel hot-air anti-icing structure of engine inlet vane is put forward and anti-icing experiment is conducted in a small open-circuit icing wind tunnel. The structure is combined with impinging jet, micro channels, and exhaust releasing exhausted hot air to sweep running-back water off the coating. The experiment is run at different simulated meteorological and bleed air conditions. The vane surface temperature and running-back water film distributions of two kinds of micro channel with channel spacing of 1.5 mm and 2 mm are obtained. The results indicate that impinging jet ensures the anti-icing effect of leading edge, smaller interval of micro channels brings better anti-icing effect at same bleed air condition, and temperature of bleed air has more influence than pressure. The vented out exhausted air protects the rear skin from running-back water icing effectively.
Ice accretion on the inlet strut of an aero-engine could affect the characteristics of the flow field into the engine. The shed ice which is sucked into the engine may lead to serious mechanical damages. Hot air anti-icing system is commonly used to prevent ice accumulating on inlet strut surface. A computational method of simulating the temperature and heat transfer of the hot air anti-icing inlet strut under icing condition is resented. The flow fields around the inlet strut and inside the strut are obtained by using CFD software Fluent. The trajectories of supercooled water droplets and the collection efficiency are calculated by Eulerian approach. The coupling effects of heat transfer and mass transfer are taken into account in the temperature simulations of the inlet strut. The thermal balance model considers the mass balance of water and energy balance on the surface of the inlet strut. The comparisons of computation results with experiment results are given to assess the validity of present coupling computation method in this paper.
The aim of the present work is to improve ice simulation methods; first by developing a mathematical model to simulate a hot air anti-icing system using the ice prediction code CANICE then, by analyzing the heat transfer phenomena on airfoil. A simple mathematical model is proposed to simulate temperature changes in the runback water film and conduction in airfoil skin. Heat flux from hot air circulating inside airfoil is estimated by way of an internal convection coefficient. It appears that runback water temperature prediction compares well to other numerical results available in litterature. Heat lost due to convection and evaporation are presented for constant temperature and constant heat flux cases. Results show that heat lost to evaporation increases faster with temperature than heat lost due to convection.
A series of experimental tests were conducted in the NASA Lewis IRT on an electro-thermally heated NACA 0012 airfoil. Quantitative comparisons between the experimental results and those predicted by a computer simulation code were made to assess the validity of a recently developed anti-icing model. An infrared camera was utilized to scan the instantaneous temperature contours of the skin surface. Despite some experimental difficulties, good agreement between the numerical predictions and the experiment results were generally obtained for the surface temperature and the possibility for each runback to freeze. Some recommendations were given for an efficient operation of a thermal anti-icing system.
s) and/or author(s)' sponsoring organization User Manu al for the Improved NASA Lewis Ice Accretion Code LEWICE 1.6 Numerical Simulation of an Aircraft Anti-Icing System Incorporating a Rivulet Model for the Runback Water
- W B Wright
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Numerical Simulation of an Aircraft Anti-Icing System Incorporating a Rivulet Model for the Runback Water
- K M Gal-Khalil