Metallspridning via dagvatten är ett problem, vilket fo ̈rväntas växa i framtiden. Det finns dock en problematik i att många metoder för dagvattenrening inte är tillräckligt effektiva gällande avskiljning av lösta metalljoner. Detta har medfört ett ökat intresse för reaktiva filtermaterial vilka avskiljer lösta metalljoner.  I dagsläget finns en begränsad kunskap om funktionen av reaktiva filter speciellt under nordiska förhållanden med kalla vintrar där dubbdäck är regel och halkbekämpning med vägsalt är vanligt.  Detta arbete är genomfört i ett fullskaleförsök under vinterförhållanden med höga salthalter och låga temperaturer i vägdagvattnet.  I undersökningen har inverkan av pH och vägsalt på avskiljningen av metaller och igensättning studerats för det reaktiva filtermaterialet Filtralitea® P. Undersökningen har genomförst vid Lilla Essingens dagvattenreningsanläggning som behandlar dagvatten från ett avrinningsomr ̊ade med en yta på 17 600 m2, varav Essingeleden med en årsdygnstrafik ( ̊ADT) på 140 000 fordon, utgör en större del av avrinningsområdet. Undersökningen genomfördes under perioden 28/01-2021 till 16/04-2021. Efter sedimente- ring pumpades vägdagvatten till två parallella filterbrunnar (Filter 1 och Filter 2) laddade med Filtralite P. Uppehållstiden i Filter 1 var fyra timmar medan uppehållstiden i Filter 2 varierade mellan 9 till 24 timmar. Den hydrauliska belastningen på Filter 1 var således avsevärt högre än för Filter 2. Turbiditeten hos det inkommande vattnet till brunnarna var väldigt låg (<46,5 FNU) och igensättning kom inte att påverka drifttiden för filtermaterialet i denna anläggning i någon större utsträckning, då tendenser till igensättning endast påvisades i Filter 1. Kloridkoncentrationen i vägdagvattnet varierade mellan 119 - 4 990 mg L−1 och temperaturen i vattnet som pumpades till de reaktiva filtren varierade mellan 0 – 6 °C. Det reaktiva filtret visade goda förmågor att avskilja partikulärt och löst zink och koppar. Järn- mangan- och kalciumkoncentrationerna avskiljdes i Filter 2, men i Filter 1 ökade ofiltrerade halten järn samt mangan- och kalciumkoncentrationerna. Detta tros bero på att den högre belastningen på Filter 1 orsakade en kraftigare pH-reduktion som i sin tur minskade adsoptionsförmågan och därmed ökade saltets påverkan. En viss avskiljning av krom observerades med undantag fär den filtrerade fraktionen efter Filter 2. Nickelkoncentrationen i utgående vatten var förhöjd i bägge filter (Filter 1: totalhalt max 9,48 μg L−1, löst halt 10,8 μg L−1, Filter 2: totalhalt max 4,08 μg L−1, löst halt 4,13 μg L−1). Koncentrationerna av magnesium och molybden var högre efter båda reaktiva filtren. Metallerna bly, kadmium och kvicksilver förekom endast i låga koncentrationer under försöken. Filter 1 påvisade i regel sämre avskiljning än Filter 2, vilket kan innebära att en lägre hydraulisk belastning resulterar i effektivare rening. Salthalten korrelerade med koncentrationerna av kalcium, järn, mangan, magnesium och zink efter filterbrunnarna och det är därmed möjligt att salthalten kan mobilisera bundna metaller. Ett tröskelvärde för mobilisering av metaller kan vara en salthalt av 2 500 mg L−1. / The growing infrastructure creates more impermeable surfaces, causing an increase in stormwater that brings contaminants from surfaces such as roofs and roads, spreading these in the environment. There are a number of different stormwater treatment methods but many lack the ability to remove metal ions. One promising method is the use of reactive filter materials. However, there is a limited amount of research conducted on how these reactive filter systems perform in natural conditions, especially in nordic environments with cold winters, de-icing salt application and usage of studded tyres. This study aims at in- vestigating how de-icing salt (NaCl), pH, temperature, clogging and water flow affect the treatment efficiency of the reactive filter material Filtralite® P in a real-life application. The catchment area that contributed water to the studied system had a total area of 17,600 m2, including parts of Essingeleden, one of the most trafficked roads in Sweden with an annual average daily traffic load of 140,000 vehicles. The studied system consisted of a stormwater pond fed with water from the catchment area. The pond connected to a measuring well which in turn was connected to a pumping well. From there, water was pumped upwards through two parallel wells (Filter 1 and Filter 2) containing Filtralite P and was then discharged into lake Ma ̈laren. Filter 1 was subjected to a higher hydraulic load compared to Filter 2, resulting i a residence time of four hours in Filter 1 and 9 - 24 hours in Filter 2. Water samples were collected in the measuring well and above the filter media in both reactive filter wells. This allowed for examination of the metal concentrations before and after the reactive filters. Measurements of pH, temperature, conductivity and turbidity were conducted in the measuring well and in both filter wells. In addition, measurements of head loss and water flow were also taken in the filter wells. The samples and measurements of this study were taken between 28/01-2021 and 16/04- 2021. Before that, the reactive filter material had been in use from June to December of 2020. The turbidity in the measuring well varied between 2 and 50 FNU. A decrease in turbidity was observed after the reactive filter media, with an average of 3.3 FNU in Filter 1 and 0.9 FNU in Filter 2. The amount of suspended solids in the water was estimated to not exceed 16 mg L−1 and in total, approximately 1.4 kg of suspended solids was removed in Filter 1 and 0.3 kg in Filter 2. The head loss through Filter 2 was highly correlated with the hydraulic load due to the drastic variations in flow. The head loss in Filter 1 was observed to increase slightly over time, indicating that clogging might start to take place. However, clogging of the filter media did not seem to be an issue for the system, a theory strengthened by the low turbidity and low increase in head loss. The temperature in the measuring well varied between 0 and 6 °C and in the filter wells between 1.1 and 7.4 °C. The low temperature might have negatively affected the efficiency of the reactive filter. An increase in pH was observed after the water passed through the reactive filters, with Filter 1 raising the pH to around 9 and Filter 2 to around 10 in the beginning of the testing period. This increase in pH would diminish over the period in Filter 1 to approximately 8, while Filter 2 maintained a stable pH increase. The conductivity increased over the measuring period and reached a peak in February to then decrease during March, most likely caused by increased and decreased use of de-icing salts. Chloride concentrations in the incoming stormwater varied between 119 - 4 990 mg L−1. The treated water after the reactive filters exhibited a reduced concentration of filtered copper and zink. Meanwhile, the concentrations of calcium, iron, manganese and nickel increased in Filter 1, but decreased in Filter 2. Filtered chromium decreased in Filter 1 but no statistically significant reduction was observed in Filter 2. However, the reduction of chromium might have been more efficient, due to a majority of measurements showing concentrations below the detection limit after the reactive fitlers. There was an increased concentration of filtered molybdenum and magnesium after the reactive filters. The metals cadmium, lead and mercury were merely present in very low concentrations or below the de- tection limit of laboratory instruments. Futher investigations of these metals were therefore not conducted. In general, Filter 2 achieved a higher metal treatment efficiency compared to Filter 1. This is believed to be caused by the higher hydraulic load in Filter 1. This caused a pH reduction in the filter material which in turn led to a reduced adsorption efficiency and possibly enhanced the competition effect between the dissolved metals and the sodium ions from the de-icing salts. A correlation was found between chloride and calcium, manganese and iron in Filter 1. In Filter 2 there was a correlation between chloride and calcium, unfiltered magnesium and zink. The chloride concentrations are related to the de-icing salts and it is believed that the salts could have an impact on the efficiency of metal reduction in Filtralite P. At chloride concentrations of around 2 500 mg L−1 the concentrations of zink, magnesium, iron, copper and calcium seemed to increase in the effluent water, meaning that there might also be a threshold value, which if passed, leads to increased metal mobilization. The higher performance of Filter 2 might also be due to longer residence times. This increa- sed residence time might have allowed for a greater reduction of metals due to an increased contact time. It is important to note that more bed volumes had passed Filter 1 compared to Filter 2, with a total of 321 bed volumes through Filter 1 and 53 bed volumes through Filter 2 during the period of this study. However, if previous bed volumes are also taken into account, a total of 1,157 bed volumes have passed Filter 1 and 559 have passed Filter 2. This could also have caused the reduced efficiency observed in Filter 1 compared to Filter 2.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Há a necessidade de prevenir formação de gelo nas asas e nos estabilizadores de aeronaves, pois as formas de gelo podem causar a degradação do desempenho aerodinâmico, o aumento de peso, bem como dificuldades de controle e manobra que, em casos críticos, leva a uma diminuição da margem de segurança operacional. Quando as aeronaves atravessam nuvens com gotículas de água sub-resfriadas, ou seja, em equilíbrio metaestável, o crescimento de gelo ocorre nas superfícies não protegidas. Usualmente, os sistemas antigelo térmicos de aerofólios são projetados, desenvolvidos e certificados com o auxílio de programas de simulação numérica. O presente trabalho visa desenvolver e implementar um modelo matemático para prever a transferência de calor e massa no escoamento bidimensional bifásico em torno de aerofólios de uso aeronáuticos, equipados com sistema de antigelo térmico operando em regime permanente. Em condições de formação de gelo, é necessário aquecer o bordo de ataque e controlar a temperatura da região protegida para que não ocorra formação de gelo. O sistema de aquecimento compensa os efeitos do resfriamento imposto principalmente pelos mecanismos acoplados de evaporação e transferência de calor por convecção, que são causados pelo escoamento do ar carregado de gotículas sub-resfriadas e pelo escoamento da água líquida residual. O modelo deverá estimar a distribuição de temperaturas de superfície e o coeficiente de transferência de calor com precisão ao uso em aplicações aeronáuticas. O presente trabalho implementou novos submodelos para: 1) estimar a molhabilidade da superfície do aerofólio por meio de um modelo matemático para caracterizar o escoamento da água líquida residual na padrão de filme e de filetes; 2) avaliar o comportamento dinâmico e térmico da camada-limite laminar e turbulenta por meio de análises integral e diferencial, que considera efeitos do gradiente de pressão, da transição laminar-turbulenta, da transpiração e da não uniformidade de temperatura da superfície e 3) estimar o início e o término da região de transição laminar-turbulenta. O presente trabalho seguiu um processo de desenvolvimento de código numérico que: verificou os resultados de cada submodelo separadamente para depois implementados no modelo do antigelo; validou os resultados da simulação de desempenho do sistema antigelo com os novos submodelos implementados. Os resultados obtidos foram considerados satisfatórios para o modelo do antigelo que utilizou os submodelos de ruptura de filme e formação de filetes pelo critério da Energia Mecânica Total Mínima, de camada-limite diferencial compressível e de previsão da transição laminar-turbulenta por correlações algébricas, que consideraram efeitos do gradiente de pressão e do nível de turbulência ao longe. / It is required to prevent ice accretion on wings and horizontal stabilizers because it may cause aerodynamic performance degradation, weight increase, flight control difficulties and, in critical cases, may lead to operational safety margins reduction. When aircraft flies through clouds containnig supercooled water droplets, which are in metastable equilibrium, ice will form in all non-protected surfaces. Usually, anti-ice protection systems are designed, developed and certified with a support from a numerical tool. The present describes the development and implementation of a mathematical model for prediction of heat and mass transfer in two-phase flow around airfoils, which are equipped with thermal anti-ice system and operating in steady state regime. Under icing conditions, it is necessary to heat and control the temperature of the airfoil surface at leading edge region to prevent ice formation. The heating system balances the evaporative cooling effects, which are caused by the coupled heat and mass convection transfer, imposed by the air flow loaded with supercooled water droplets and the runback water flow around the airfoil. The present work implemented submodels to: 1) estimate airfoil surface wetness factor by adopting a liquid water film flow model as well as a rivulet formation and flow model; 2) evaluate laminar and turbulent boundary layers with pressure gradient and laminar-turbulent transition over nonisothermal and permeable airfoil surface by implementing differential boundary layer analysis and 3) predict the onset position and length of laminar-turbulent transition region. The present paper followed a validation and verification process during the numerical code development. All sub-models results were verified separately against experimental data before their inclusion in anti-ice model.The results of anti-ice model with selected submodels were validated against reference cases. The results were considered suficiently accurate when solving the film breakdown and rivulets formation by total mechanical energy method, compressible boundary layer by differential analysis and laminar-turbulent transition prediction by algebraic correlations, which considered pressure gradient and freestream turbulence level.

No presente trabalho foi implementado um modelo matemático para simular o sistema antigelo eletrotérmico de um aerofólio. Por meio do programa ONERA2D simulou-se o escoamento potencial completo com velocidade 44,7 m/s (100 mph) e 89,4 m/s (200 mph) em torno de um aerofólio perfil NACA0012 de corda 0,914 m (3 pés) com ângulo de ataque de 0°, e calculou-se a eficiência de coleta local de gotículas de água com diâmetro mediano volumétrico de 20 μm. Foram simuladas quatro condições de teste com diferentes distribuições de fluxo de calor nos aquecedores elétricos do sistema antigelo. O modelo previu a distribuição de temperaturas na superfície sólida do aerofólio e no filme de água líquida, e as distribuições de fluxo de água líquida sobre a superfície do aerofólio (\"runback water\") e de coeficiente de transferência de calor por convecção de calor entre a superfície do aerofólio e o escoamento gasoso. Os resultados da simulação obtidos com o modelo foram comparados com resultados experimentais da NASA e os resultados numéricos dos programas LEWICE/ANTICE (EUA) e CANICE (Canada). Para as regiões molhadas pelo filme de água líquida, obteve-se um desvio máximo de temperatura de 2,6°C entre os resultados do presente modelo e o resultados experimentais. Para as regiões secas, onde não existe o filme de água líquida sobre a superfície do aerofólio, obteve-se um desvio de máximo de temperatura de 8°C. As previsões para distribuição de vazão de \"runback\", posição do término do filme de água líquida foram comparadas com os resultados do programa LEWICE/ANTICE. O modelo desenvolvido simula com adequada aproximação os efeitos da transferência de calor e de massa por convecção entre a superfície não-isotérmica do aerofólio ou do filme de água líquida e o escoamento gasoso, bem como os efeitos da transição entre o escoamento laminar e o turbulento na camada limite dinâmica e térmica e ainda a influência do escoamento do filme de água líquida sobre o desempenho do sistema de antigelo do aerofólio. / An electro-thermal anti-ice system was simulated with a mathematical model developed in the present work. A 44.7 m/s (100 mph) and 89.4 m/s (200 mph) full potential flow around a 0.914 m (3 ft) chord NACA0012 airfoil with 0° angle of attack and the local water catch efficiency of 20 μm median volumetric diameter droplets impingement were calculated by the numerical code ONERA2D. Four test conditions were simulated with four different heat flux distributions of the anti-ice system according to the experimental work developed at NASA. The model predicted distributions of solid surface and liquid water film temperatures, runback water flow and convection heat transfer coefficient between airfoil or water surface and gaseous flow. The simulated results obtained by the mathematical model developed were compared to NASA experimental results and the ones predicted by the numerical codes LEWICE/ANTICE (US) and CANICE (Canada). For the regions wetted by the water film, the present model provided 2.6°C maximum temperature deviations between the predicted results and experimental data. For the dry regions, where there is no liquid water on the airfoil surface, an 8°C maximum temperature deviation was obtained. The runback flow and water film ending point position were compared to LEWICE/ANTICE numerical results. The developed model predicts adequately the convection heat and mass transfer effects between the non-isothermal airfoil or liquid water film surface and the gaseous flow, as well the effects of laminar to turbulent flow transition within dynamic and thermal boundary layer and the influence of the liquid water film flow on the anti-ice system performance.

No presente trabalho foi implementado um modelo matemático para simular o sistema antigelo eletrotérmico de um aerofólio. Por meio do programa ONERA2D simulou-se o escoamento potencial completo com velocidade 44,7 m/s (100 mph) e 89,4 m/s (200 mph) em torno de um aerofólio perfil NACA0012 de corda 0,914 m (3 pés) com ângulo de ataque de 0°, e calculou-se a eficiência de coleta local de gotículas de água com diâmetro mediano volumétrico de 20 μm. Foram simuladas quatro condições de teste com diferentes distribuições de fluxo de calor nos aquecedores elétricos do sistema antigelo. O modelo previu a distribuição de temperaturas na superfície sólida do aerofólio e no filme de água líquida, e as distribuições de fluxo de água líquida sobre a superfície do aerofólio (\"runback water\") e de coeficiente de transferência de calor por convecção de calor entre a superfície do aerofólio e o escoamento gasoso. Os resultados da simulação obtidos com o modelo foram comparados com resultados experimentais da NASA e os resultados numéricos dos programas LEWICE/ANTICE (EUA) e CANICE (Canada). Para as regiões molhadas pelo filme de água líquida, obteve-se um desvio máximo de temperatura de 2,6°C entre os resultados do presente modelo e o resultados experimentais. Para as regiões secas, onde não existe o filme de água líquida sobre a superfície do aerofólio, obteve-se um desvio de máximo de temperatura de 8°C. As previsões para distribuição de vazão de \"runback\", posição do término do filme de água líquida foram comparadas com os resultados do programa LEWICE/ANTICE. O modelo desenvolvido simula com adequada aproximação os efeitos da transferência de calor e de massa por convecção entre a superfície não-isotérmica do aerofólio ou do filme de água líquida e o escoamento gasoso, bem como os efeitos da transição entre o escoamento laminar e o turbulento na camada limite dinâmica e térmica e ainda a influência do escoamento do filme de água líquida sobre o desempenho do sistema de antigelo do aerofólio. / An electro-thermal anti-ice system was simulated with a mathematical model developed in the present work. A 44.7 m/s (100 mph) and 89.4 m/s (200 mph) full potential flow around a 0.914 m (3 ft) chord NACA0012 airfoil with 0° angle of attack and the local water catch efficiency of 20 μm median volumetric diameter droplets impingement were calculated by the numerical code ONERA2D. Four test conditions were simulated with four different heat flux distributions of the anti-ice system according to the experimental work developed at NASA. The model predicted distributions of solid surface and liquid water film temperatures, runback water flow and convection heat transfer coefficient between airfoil or water surface and gaseous flow. The simulated results obtained by the mathematical model developed were compared to NASA experimental results and the ones predicted by the numerical codes LEWICE/ANTICE (US) and CANICE (Canada). For the regions wetted by the water film, the present model provided 2.6°C maximum temperature deviations between the predicted results and experimental data. For the dry regions, where there is no liquid water on the airfoil surface, an 8°C maximum temperature deviation was obtained. The runback flow and water film ending point position were compared to LEWICE/ANTICE numerical results. The developed model predicts adequately the convection heat and mass transfer effects between the non-isothermal airfoil or liquid water film surface and the gaseous flow, as well the effects of laminar to turbulent flow transition within dynamic and thermal boundary layer and the influence of the liquid water film flow on the anti-ice system performance.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Depuis de nombreuses années, le givrage a été identifié comme un danger dans le domaine de l’aéronautique.L’accrétion de givre se produit lorsque des gouttelettes d’eau surfondue se déposent sur une surface, enparticulier le bord d’attaque d’une aile ou la lèvre d’entrée d’air moteur, et gèlent après l’impact. Ceci peutensuite engendrer une dégradation des performances aérodynamiques, un dysfonctionnement des sondes ouencore un endommagement du moteur. C’est pourquoi cette problématique est étudiée avec attention. Lesessais en vol et en soufflerie étant longs et coûteux, la simulation numérique de l’accrétion de givre est devenueun outil nécessaire dans le processus de conception et de certification des avions. Cette thèse s’inscrit dans le contexte de la modélisation 3D de l’accrétion de givre, et plus particulièrement des couches limites dynamique et thermique qui se développent autour du corps givré. Les outils numériques devant être rapides et robustes, l’approche proposée dans cette thèse pour le calcul aérodynamique est une méthode couplée Euler/couche limite intégrale. Ainsi, un modèle intégral est développé pour représenterle développement de la couche limite dynamique. La partie thermique est modélisée soit par une méthodesimplifiée basée sur des approches algébriques, soit par une méthode intégrale. Cette modélisation des coucheslimites dynamique et thermique est valable sur paroi lisse ou rugueuse et permet de fournir notamment lecoefficient de frottement et le coefficient d’échange thermique qui sont nécessaires pour un calcul d’accrétion degivre. Les équations intégrales de couche limite, associées à leurs relations de fermeture, sont ensuite résoluespar une méthode Volumes-Finis sur maillage surfacique non structuré, qui est bien adaptée pour les géométriescomplexes. De plus, des traitements numériques spécifiques sont mis en œuvre pour améliorer la précision dela méthode au voisinage du point d’arrêt et pour rendre le code robuste au passage du décollement.Après la validation de la méthode de couche limite, le code est utilisé dans les chaînes de givrage 2D et 3Dde l’ONERA pour des applications d’accrétion de givre. Ceci permet de montrer l’intérêt de la méthode entermes de robustesse et de précision par rapport aux codes de couche limite habituellement utilisés dans lescodes de givrage actuels. / Icing has since long been identified as a serious issue in the aeronautical world. Ice accretion occurs whensupercooled water droplets impinge on a surface, particularly the leading edge of a wing or an engine inlet, andfreeze after the impingement. This can lead to degradation of aerodynamic performances, sensor malfunctionor engine damage. This is why this issue is being carefully studied. The lengthy and costly flight and windtunnel tests have made numerical simulation of ice accretion a necessary tool in the aircraft design andcertification process. The present work deals with the 3D numerical modeling of ice accretion, and more particularly the modeling of the dynamic and thermal boundary layers that develop around an iced body. Since numerical tools must befast and robust, the approach proposed in this thesis for aerodynamic computation is a coupled Euler/integralboundary layer method. Thus, an integral model is developed to represent the development of the dynamicboundary layer. The thermal part is modeled either by a simplified method based on algebraic approaches,or by an integral method. This modeling of the dynamic and thermal boundary layers is valid on smoothor rough walls and provides the friction coefficient and heat exchange coefficient that are necessary for thecalculation of ice accretion. The integral boundary layer equations, associated with their closure relations,are then solved by a Finite-Volume method on unstructured surface mesh, that is well suited for complexgeometries. In addition, specific numerical treatments are implemented to improve the accuracy of the methodin the vicinity of the stagnation point and to make the code robust to separated boundary layers.After validation of the boundary layer method, the code is used in ONERA’s 2D and 3D icing tools foricing applications. This demonstrates the value of the method in terms of robustness and accuracy comparedto the boundary layer codes more commonly used in current icing tools.

Há a necessidade de prevenir formação de gelo nas asas e nos estabilizadores de aeronaves, pois as formas de gelo podem causar a degradação do desempenho aerodinâmico, o aumento de peso, bem como dificuldades de controle e manobra que, em casos críticos, leva a uma diminuição da margem de segurança operacional. Quando as aeronaves atravessam nuvens com gotículas de água sub-resfriadas, ou seja, em equilíbrio metaestável, o crescimento de gelo ocorre nas superfícies não protegidas. Usualmente, os sistemas antigelo térmicos de aerofólios são projetados, desenvolvidos e certificados com o auxílio de programas de simulação numérica. O presente trabalho visa desenvolver e implementar um modelo matemático para prever a transferência de calor e massa no escoamento bidimensional bifásico em torno de aerofólios de uso aeronáuticos, equipados com sistema de antigelo térmico operando em regime permanente. Em condições de formação de gelo, é necessário aquecer o bordo de ataque e controlar a temperatura da região protegida para que não ocorra formação de gelo. O sistema de aquecimento compensa os efeitos do resfriamento imposto principalmente pelos mecanismos acoplados de evaporação e transferência de calor por convecção, que são causados pelo escoamento do ar carregado de gotículas sub-resfriadas e pelo escoamento da água líquida residual. O modelo deverá estimar a distribuição de temperaturas de superfície e o coeficiente de transferência de calor com precisão ao uso em aplicações aeronáuticas. O presente trabalho implementou novos submodelos para: 1) estimar a molhabilidade da superfície do aerofólio por meio de um modelo matemático para caracterizar o escoamento da água líquida residual na padrão de filme e de filetes; 2) avaliar o comportamento dinâmico e térmico da camada-limite laminar e turbulenta por meio de análises integral e diferencial, que considera efeitos do gradiente de pressão, da transição laminar-turbulenta, da transpiração e da não uniformidade de temperatura da superfície e 3) estimar o início e o término da região de transição laminar-turbulenta. O presente trabalho seguiu um processo de desenvolvimento de código numérico que: verificou os resultados de cada submodelo separadamente para depois implementados no modelo do antigelo; validou os resultados da simulação de desempenho do sistema antigelo com os novos submodelos implementados. Os resultados obtidos foram considerados satisfatórios para o modelo do antigelo que utilizou os submodelos de ruptura de filme e formação de filetes pelo critério da Energia Mecânica Total Mínima, de camada-limite diferencial compressível e de previsão da transição laminar-turbulenta por correlações algébricas, que consideraram efeitos do gradiente de pressão e do nível de turbulência ao longe. / It is required to prevent ice accretion on wings and horizontal stabilizers because it may cause aerodynamic performance degradation, weight increase, flight control difficulties and, in critical cases, may lead to operational safety margins reduction. When aircraft flies through clouds containnig supercooled water droplets, which are in metastable equilibrium, ice will form in all non-protected surfaces. Usually, anti-ice protection systems are designed, developed and certified with a support from a numerical tool. The present describes the development and implementation of a mathematical model for prediction of heat and mass transfer in two-phase flow around airfoils, which are equipped with thermal anti-ice system and operating in steady state regime. Under icing conditions, it is necessary to heat and control the temperature of the airfoil surface at leading edge region to prevent ice formation. The heating system balances the evaporative cooling effects, which are caused by the coupled heat and mass convection transfer, imposed by the air flow loaded with supercooled water droplets and the runback water flow around the airfoil. The present work implemented submodels to: 1) estimate airfoil surface wetness factor by adopting a liquid water film flow model as well as a rivulet formation and flow model; 2) evaluate laminar and turbulent boundary layers with pressure gradient and laminar-turbulent transition over nonisothermal and permeable airfoil surface by implementing differential boundary layer analysis and 3) predict the onset position and length of laminar-turbulent transition region. The present paper followed a validation and verification process during the numerical code development. All sub-models results were verified separately against experimental data before their inclusion in anti-ice model.The results of anti-ice model with selected submodels were validated against reference cases. The results were considered suficiently accurate when solving the film breakdown and rivulets formation by total mechanical energy method, compressible boundary layer by differential analysis and laminar-turbulent transition prediction by algebraic correlations, which considered pressure gradient and freestream turbulence level.

The diploma thesis deals with different methods of determining levels of degradation of concrete due to freezing, also considering the options of freeze thaw resistance determination in structure. At first the properties of concrete and possible mechanisms of concrete degradation are described – mainly the effects of freezing water in the inner structure and of the combination of freezing water and de-icing chemicals on the surface. Principle and properties of air-entrained concrete are also mentioned. An overview of the approaches that current standards use to determine the freeze-thaw resistance of concrete is listed, followed by description of the tests that are used on air-entrained concrete specimens in the main part of the thesis. A portion of the test specimens was made in moulds while the rest was obtained from structure (concrete block). The non-destructive tests used are evaluated in several different ways and their results are compared with the destructive tests. Comparison and evaluation of different approaches used to determine the freeze-thaw resistence of concrete are the main outcome of this thesis.

The thesis is aimed at deepening knowledge about the design and use of open-graded asphalt concrete filled with a special cement grout. The first part is the issue discussed theoretically with reference to the real possibility of practical application, a description of the various manufacturers and their patented technologies. The second part of this work is devoted to assess the resistance of this technology to chemical de-icing agents.