Chemical reactions can have a staggering amount of molecular complexity. Reaction mechanisms have been proposed with over one hundred elementary reaction steps that occur in the same system simultaneously. While several methods exist to simplify and make sense of the pathways and kinetics via which these reactions proceed, e.g., reaction graphs, sensitivity or flux analysis, microkinetic analysis, and comparison of energy landscapes, etc., these methods all have limitations and are often not able to capture a comprehensive picture of the kinetics of system. It has been found useful to view these mechanisms as a network, i.e., a reaction graph. These graphs enable the visualization of the pathways of the reaction and can provide an analytical tool for pathway and kinetic analysis. However, many of the specific graph-theoretic approaches in the literature are not the most suitable for kinetic analysis of complex mechanisms; as they are simply not based on rules that are rigorous enough to fully enumerate all the pathways or provide quantitative analysis of the reaction rates. Our Reaction Route (RR) Graph approach is different in that it depicts the mechanism by a graph that is consistent with all physical and chemical laws associated with reaction networks, particularly being consistent with mass and energy conservation, i.e., Kirchoff’s Flux Law (KFL) and Kirchoff’s Potential Law (KPL). Because of their adherence to these laws, RR Graphs are able to provide an accurate graph-theoretical tool not only for depicting all reactions routes as walks (hence the name RR Graph) but also for pruning mechanisms and allowing a simplified but accurate quantitative description of reaction rates. This adherence to KFL and KPL does mean that the construction and implementation of these graphs can be prohibitively difficult for large mechanisms. For large reaction systems,especially nonlinear mechanisms, it is not realistic to generate these graphs by hand. And although there exists an analytical solution to find a determinant matrix for the RR Graph of a mechanism, the process involves an exhaustive search for a solution which experiences a combinatorial explosion as the number of steps gets very large. This leads to the idea of developing an algorithm for a computer program that can determine how to generate these graphs automatically. Unfortunately, the same combinatorial explosion is present such that for a moderately sized twenty step mechanism, it could take an average computational processor over a decade to find a solution. We have determined, however, that this brute force combinatorial approach can be avoided if heuristics could be developed to bridge gaps in our knowledge of how these graphs are constructed. Thus, developing a better analytical approach and/or a tighter set of heuristics for a computer algorithm are the overarching goals of this work. To make progress toward developing such heuristics, a set of microkinetic mechanisms were analyzed with the notion that the realization of the RR Graphs would highlight a better approach to their construction and usage. In particular, a very large linear reaction system, a smaller linear system and two non-linear reaction systems were analyzed to develop insights into how each graph is manually constructed and analyzed. Furthermore, kinetic analysis was done for these mechanisms and compared to experimental data and other analytical tools to prove not only the validity of the RR Graphs, but also how they are a significant improvement over more commonly used approaches for mechanistic and kinetic analysis. Based on the lessons learned through a consideration of these examples, a set of heuristics are established and enumerated with the ultimate goal of developing an intuitive algorithm that can help automate drawing and kinetic analysis via RR Graphs of complex mechanisms.

Distributed hydrogen generation from liquid hydrocarbon fuels to supply portable fuel cells presents an attractive, high energy density alternative to current battery technology. Traditional unit operation reactor design for hydrogen generation becomes inadequate with decrease in scale because of the unique challenges of size and weight minimization. To address the challenge of reactor scale-down, the concept of multifunctional reactors has emerged, in which synergistic combination of different unit operations is explored to achieve improved performance. The direct droplet impingement reactor (DDIR) studied here is based on this approach in which the liquid feed is atomized using a regularly spaced array of droplet generators with unparalleled control over droplet characteristics, followed by vaporization and reaction directly on the catalyst surface. Considering each droplet generator in the array as a unit cell, a comprehensive, first-principles model of the DDIR has been developed by considering the intimately coupled processes of 1) droplet transport, heating, evaporation, and impingement on the catalyst surface, 2) liquid reagent film formation, capillary penetration, and vaporization within the catalyst layer, and 3) gas phase heat and mass transfer and catalytic reactions. Simulations are performed to investigate the effect of reactor operating parameters on performance. Experimental validation of the model is carried out by visualizing droplet impingement and liquid film accumulation while simultaneously monitoring reaction product composition over a range of operating conditions. Results suggest an optimal unit cell shape for reaction selectivity based on a balance between reagent back diffusion and catalyst bed thermal resistance. Further, achieving a target throughput is best accomplished by adding together a larger number unit cells with optimized geometry and lower throughput (per unit cell) to more effectively spread heat and avoid hotspots at the catalyst interface. At the same time, conditions must be satisfied for ensuring droplet impingement on the catalyst surface, which become more stringent as unit cell throughput is decreased.

Dans le cadre de la recherche de vecteurs d'énergie “propres”, le borazane et ses dérivés amine-boranes sont devenus des candidats intéressants en tant que matériaux de stockage de l'hydrogène en raison de leur pourcentage massique relativement élevé en hydrogène (19,6% pour borazane) et de la réversibilité potentielle de la réaction de déshydrogénation. Pour des applications réelles, le contrôle des réactions se produisant à la température ambiante est fondamental. Dans ce contexte, la compréhension du processus de la déshydrogénation/déshydrocouplage catalytique de l'amine-borane apparaît comme un élément important. Dans cette thèse, les catalyseurs de types métallocènes du Groupe IV (Cp2M, M = Ti, Zr et Hf) sont étudiés en détail. Le déshydrocouplage de HMe2N·BH3 catalysé par le titanocène a été étudié à la fois expérimentalement et théoriquement mais aucun accord n'avait été atteint auparavant. Dans ce travail, les caractérisations systématiques des interactions 3-centre 2-électron M···H-B impliquées dans les intermédiaires réactionnels ont été réalisées avec des approches topologiques QTAIM et ELF. Par la suite, des mécanismes réactionnels détaillés ont été étudiés. Les résultats théoriques ont démontré que la méthode DFT corrigée avec la dispersion (DFT-D) étaient nécessaire et suffisantes pour une description énergétique correcte des chemins réactionnels. Mon travail a également permis l'identification d'un complexe de van der Waals jouant un rôle clé dans le mécanisme réactionnel en accord avec les observations expérimentales. / With the increasing demand of clean energy carriers, ammonia borane and its related amine-borane compounds have emerged as attractive candidates for hydrogen storage materials due to their relatively high weight percentage of available hydrogen (19.6% for ammonia borane) as well as the potential reversibility for the hydrogen release reactions. Actual applications would benefit from controlled reactions occurring close to room-temperature. In this context, catalytic dehydrogenation/dehydrocoupling of amine-borane appears as a promising solution. In this thesis the Group IV metallocene (Cp2M, M = Ti, Zr and Hf) are mainly discussed. The dehydrocoupling of HMe2N·BH3 catalyzed by titanocene was investigated both experimentally and theoretically but no agreement were reached. In this work, systematic characterization of M···H-B 3-center 2-electron interactions involved in reaction intermediates were carried out with QTAIM and ELF topological approaches. Afterwards, detailed mechanisms were further studied. Computational results have demonstrated that the dispersion corrected DFT (DFT-D) method was indispensable for a correct enegetic prediction for reaction pathways. The identification of a van der Waals complexe also plays a central role for a reaction mechanism with good agreement with experimental observations.

O comportamento eletroquímico do Nitrofural (NFZ) foi estudado em eletrodos de pasta de carbono, carbono vítreo e diamante altamente dopado com boro (EDADB) em tampão Britton-Robinson (BR) usando a voltametria cíclica. Os melhores resultados foram obtidos em EDADB, no qual foi possível estabilizar o radical aniônico (R-NO2•&#8254) em meio predominantemente aquoso, como também estudar a interação entre o R-NO2•‾ a glutationa (GSH), a L-cisteína (Cis) e o O2. Somente na superfície do EDADB, o NFZ foi diretamente reduzido à amina derivada (R-NH2) no intervalo de 2,02 ≤ pH ≤ 4,03 num processo envolvendo seis (6,0 ± 0,4) elétrons e seis prótons. Na faixa de 7,04 &#8804 pH ≤ 12 e meio predominantemente aquoso, a etapa de redução desmembrou-se em seus dois componentes: a redução do NFZ ao nitro radical aniônico (R-NO2•‾) e posterior redução deste ao derivado hidroxilamínico (R-NHOH) em processos envolvendo um e três (3,1 ± 0,1) elétrons respectivamente. No sentido anódico da varredura dos voltamogramas cíclicos registrados em pH 8,06, observou-se a oxidação da hidroxilamina ao derivado nitroso (R-NO), num processo envolvendo 2 (1,7 ± 0,2) elétrons e 2 prótons. Além disto, um novo pico de oxidação não relatado na literatura em qualquer material de eletrodo foi detectado em pH ≤ 8,06, que foi observado não importando se o NFZ havia sido previamente reduzido ou não. O cálculo do número de elétrons, n, envolvido em cada etapa eletroquímica foi satisfatoriamente estimado usando-se a equação de Randles-Sevcik. Na presença de [Tiol] ≤ 3,7 x 10-2 mol L-1, o NFZ é reduzido ao aduto R-NO-Tiol em um processo eletroquímico envolvendo dois elétrons e dois prótons. Por outro lado, o O2 atua como um aceptor de R-NO2•‾ e a constante de equilíbrio para a transferência monoeletrônica do R-NO2•‾ para o oxigênio, kO2, é 60. O processo é catalítico e pode ser utilizado para a determinação analítica de NFZ na faixa de 9,9 x 10-7 ≤ [NFZ] ≤ 1,1 x 10-5 mol L-1 em pH 8,06, com sensibilidade amperométrica de 2,2 x 104 µA L mol-1 cm-2 e limite de detecção de 3,4 x 10-7 mol L-1. Os parâmetros analíticos foram similares aqueles obtidos em pH 4,0 usando a redução direta do NFZ à respectiva amina derivada em um processo envolvendo seis elétrons e seis prótons. A caracterização do processo de redução total do NFZ em meio aquoso e velocidades de varredura relativamente baixas, 100 mV s-1, somente foi possível devido às características superficiais intrínsecas do EDADB, o qual estabiliza o radical livre, R-NO2•‾, permitindo trabalhar numa ampla janela de potencial, sem haver perda do sinal de oxidação do R-NO2•‾. / The electrochemical behaviour of nitrofural (NFZ) at carbon paste, glassy carbon and highly boron doped diamond (HBDD) electrodes was studied in Britton- Robinson (BR) buffer using cyclic voltammetry. The best results were obtained at HBDD electrodes, in which it was possible to stabilize the radical anion (R-NO2•‾) in predominantly aqueous medium as well as to study the interaction between the radical anion and glutathione (GSH), L-cysteine (Cys), and O2. Only at HBDD surface, NFZ was directly reduced to the amine derivative (R-NH2) in the pH range of 2.02 to 4.03 in a process involving six (6.0 ± 0.4) electrons and six protons. In the range of pH 7.04 to 12 and, predominantly aqueous medium, the reduction step split into its two components: the reduction of NFZ to the nitro radical anion (R-NO2•‾) and reduction of R-NO2•‾ to hydroxylamine derivative (R--NHOH) in processes involving one and three (3.1 ± 0.1) electrons respectively. On the anodic scan of the cyclic voltammograms and at pH 8.06, it was observed the oxidation of the hydroxylamine to the nitroso derivative (R-NO), in a process involving 2 (1.7 ± 0.2) electrons and 2 protons. In addition and unreported in the literature on any electrode material, was the detection of a new oxidation peak at pH > 8.06, which was observed regardless of whether NFZ had been previously reduced or not. The calculation of n, number of electrons, involved in each electrochemical step was satisfactorily accomplished using the Randles-Sevcik equation. In presence of [Thiol] ≤ 3.7 x 10-2 mol L-1 NFZ is directly reduced to R-NO---Thiol adducts in an electrochemical process involving two electrons and two protons. On the other side, O2 acts as a R-NO2•‾ scavenger and the equilibrium constant for the electron transfer from nitro radical to oxygen, kO2, is 60. The process is catalytic and can be used to the analytical determination of NFZ in the range of 9.9 x 10-7 ≤ [NFZ] ≤ 1.1 x 10-5 mol L-1 at pH 8.0, with amperometric sensitivity of 2.2 x 104 µA L mol-1 cm-2 and detection limit of 3.4 x 10-7 mol L-1. The analytical parameters were similar to those obtained at pH 4.03 using the direct reduction of NFZ to the respective amine derivative in a process involving six electrons and six protons. The characterization of NFZ global reduction process in aqueous medium and at relative low scan rate, 100 mVs-1, was only possible due the intrinsic superficial characteristics of the HBDD electrode, which stabilize the R-NO2•‾ free radical, allowing to work in a large potential window, without losing the R-NO2•‾ oxidation signal.

O comportamento eletroquímico do Nitrofural (NFZ) foi estudado em eletrodos de pasta de carbono, carbono vítreo e diamante altamente dopado com boro (EDADB) em tampão Britton-Robinson (BR) usando a voltametria cíclica. Os melhores resultados foram obtidos em EDADB, no qual foi possível estabilizar o radical aniônico (R-NO2•&#8254) em meio predominantemente aquoso, como também estudar a interação entre o R-NO2•‾ a glutationa (GSH), a L-cisteína (Cis) e o O2. Somente na superfície do EDADB, o NFZ foi diretamente reduzido à amina derivada (R-NH2) no intervalo de 2,02 ≤ pH ≤ 4,03 num processo envolvendo seis (6,0 ± 0,4) elétrons e seis prótons. Na faixa de 7,04 &#8804 pH ≤ 12 e meio predominantemente aquoso, a etapa de redução desmembrou-se em seus dois componentes: a redução do NFZ ao nitro radical aniônico (R-NO2•‾) e posterior redução deste ao derivado hidroxilamínico (R-NHOH) em processos envolvendo um e três (3,1 ± 0,1) elétrons respectivamente. No sentido anódico da varredura dos voltamogramas cíclicos registrados em pH 8,06, observou-se a oxidação da hidroxilamina ao derivado nitroso (R-NO), num processo envolvendo 2 (1,7 ± 0,2) elétrons e 2 prótons. Além disto, um novo pico de oxidação não relatado na literatura em qualquer material de eletrodo foi detectado em pH ≤ 8,06, que foi observado não importando se o NFZ havia sido previamente reduzido ou não. O cálculo do número de elétrons, n, envolvido em cada etapa eletroquímica foi satisfatoriamente estimado usando-se a equação de Randles-Sevcik. Na presença de [Tiol] ≤ 3,7 x 10-2 mol L-1, o NFZ é reduzido ao aduto R-NO-Tiol em um processo eletroquímico envolvendo dois elétrons e dois prótons. Por outro lado, o O2 atua como um aceptor de R-NO2•‾ e a constante de equilíbrio para a transferência monoeletrônica do R-NO2•‾ para o oxigênio, kO2, é 60. O processo é catalítico e pode ser utilizado para a determinação analítica de NFZ na faixa de 9,9 x 10-7 ≤ [NFZ] ≤ 1,1 x 10-5 mol L-1 em pH 8,06, com sensibilidade amperométrica de 2,2 x 104 µA L mol-1 cm-2 e limite de detecção de 3,4 x 10-7 mol L-1. Os parâmetros analíticos foram similares aqueles obtidos em pH 4,0 usando a redução direta do NFZ à respectiva amina derivada em um processo envolvendo seis elétrons e seis prótons. A caracterização do processo de redução total do NFZ em meio aquoso e velocidades de varredura relativamente baixas, 100 mV s-1, somente foi possível devido às características superficiais intrínsecas do EDADB, o qual estabiliza o radical livre, R-NO2•‾, permitindo trabalhar numa ampla janela de potencial, sem haver perda do sinal de oxidação do R-NO2•‾. / The electrochemical behaviour of nitrofural (NFZ) at carbon paste, glassy carbon and highly boron doped diamond (HBDD) electrodes was studied in Britton- Robinson (BR) buffer using cyclic voltammetry. The best results were obtained at HBDD electrodes, in which it was possible to stabilize the radical anion (R-NO2•‾) in predominantly aqueous medium as well as to study the interaction between the radical anion and glutathione (GSH), L-cysteine (Cys), and O2. Only at HBDD surface, NFZ was directly reduced to the amine derivative (R-NH2) in the pH range of 2.02 to 4.03 in a process involving six (6.0 ± 0.4) electrons and six protons. In the range of pH 7.04 to 12 and, predominantly aqueous medium, the reduction step split into its two components: the reduction of NFZ to the nitro radical anion (R-NO2•‾) and reduction of R-NO2•‾ to hydroxylamine derivative (R--NHOH) in processes involving one and three (3.1 ± 0.1) electrons respectively. On the anodic scan of the cyclic voltammograms and at pH 8.06, it was observed the oxidation of the hydroxylamine to the nitroso derivative (R-NO), in a process involving 2 (1.7 ± 0.2) electrons and 2 protons. In addition and unreported in the literature on any electrode material, was the detection of a new oxidation peak at pH > 8.06, which was observed regardless of whether NFZ had been previously reduced or not. The calculation of n, number of electrons, involved in each electrochemical step was satisfactorily accomplished using the Randles-Sevcik equation. In presence of [Thiol] ≤ 3.7 x 10-2 mol L-1 NFZ is directly reduced to R-NO---Thiol adducts in an electrochemical process involving two electrons and two protons. On the other side, O2 acts as a R-NO2•‾ scavenger and the equilibrium constant for the electron transfer from nitro radical to oxygen, kO2, is 60. The process is catalytic and can be used to the analytical determination of NFZ in the range of 9.9 x 10-7 ≤ [NFZ] ≤ 1.1 x 10-5 mol L-1 at pH 8.0, with amperometric sensitivity of 2.2 x 104 µA L mol-1 cm-2 and detection limit of 3.4 x 10-7 mol L-1. The analytical parameters were similar to those obtained at pH 4.03 using the direct reduction of NFZ to the respective amine derivative in a process involving six electrons and six protons. The characterization of NFZ global reduction process in aqueous medium and at relative low scan rate, 100 mVs-1, was only possible due the intrinsic superficial characteristics of the HBDD electrode, which stabilize the R-NO2•‾ free radical, allowing to work in a large potential window, without losing the R-NO2•‾ oxidation signal.

科学研究費補助金 研究種目:一般研究(B) 課題番号:06452428 研究代表者:松田 仁樹 研究期間:1994-1995年度

Le contexte industriel est favorable aux échangeurs-réacteurs catalytiques intensifiés puisqu’ils permettent une diminution des limitations aux transferts de matière et de chaleur comparé aux réacteurs conventionnels. Toutefois, l'industrialisation de ces unités est problématique à cause de l'absence de logiciel d’ingénierie de prédiction et d’optimisation de leurs performances. Afin de construire un tel outil, les écoulements, les transferts de matière interne et externe liés aux réactions catalytiques hétérogènes, les transferts de chaleur convectif, conductif, diffusif et par rayonnement sont d’abord analysés, permettant de formuler des hypothèses simplificatrices. Les phénomènes pertinents identifiés sont ensuite mis en équations pour créer la base physique de ProSec Réaction, le nouveau logiciel de simulation des échangeurs-réacteurs. Ce logiciel est validé par comparaison avec les résultats expérimentaux du pilote de vaporeformage du méthane d'Air Liquide et par confrontation avec des simulations tri-dimensionnelles de celui-ci (CFD). L'excellente adéquation entre les résultats expérimentaux et numériques démontre le potentiel de prédiction du modèle mono-dimensionnel développé. Dans le cas particulier des échangeurs-réacteurs à plaques et ailettes catalytiques (wash-coat), une représentation bi-dimensionnelle discrète est construite et permet de tenir compte des effets thermiques radiaux intrinsèques à ces échangeurs particuliers. Enfin, ProSec Réaction est exploité pour évaluer les perspectives d'optimisation géométrique des canaux de l'échangeur-réacteur du pilote d'Air Liquide. Celles-ci montrent la flexibilité et l'intérêt de ce nouvel outil de simulation / Intensified heat exchanger reactors are promising technologies in the current industrial context because of their high potential to significantly reduce heat and mass transfer limitations compared to conventional reactors. However, the absence of simulation software for predicting their performances and optimising their geometry inside a flowsheet is limiting the industrialisation of these units. Preliminary to the development of such a simulation tool, flow characteristics, internal and external mass transfers inherent to heterogeneous catalytic reactions, convective, conductive, diffusive and radiative heat transfers are analysed, allowing the definition of simplifying assumptions. The identified relevant phenomena are then modelled and constitute the physical base of ProSec Reaction, the new heat exchanger-reactor simulation software. This software is validated by comparing the predicted values to the Air Liquide steam reforming pilot plant results and to three-dimensional simulation results as well (CFD). The excellent consistency between numerical and experimental results demonstrates the accuracy and the predictive potential of the developed one-dimensional model. In the specific case of wall-coated plate-fin heat exchanger reactors, a discrete two-dimensional model is built and allows the representation of radial temperature gradients in the material, which are intrinsic to these specific heat exchangers. Finally, optimisation perspectives of the Air Liquide pilot plant heat exchanger reactor channel geometry are evaluated thanks to ProSec Reaction. They demonstrate the flexibility and the benefits of this new simulation tool

The legislation has forced the vehicle industry to reduce tail-end emissions. The air pollutant nitrogen oxide (NOX) has been shown to have a negative impact on human health and the environment. One of the key technologies to reduce the levels of NOX emitted from a vehicle is by implementing an after-treatment system. The after-treatment system includes catalysts, a particle filter and an evaporation system. In the evaporation system a liquid jet containing a urea-water solution known as AdBlue is injected into the hot exhaust gases to evaporate into gaseous ammonia NH3 and water H2O. Then NH3 enters the Selective Catalytic Reduction (SCR) catalyst where it chemically reacts with NOX to form N2 and H2O. Problems can arise if an excessive amount of AdBlue is injected and a fluid film is formed on evaporation surfaces. At certain operating conditions the fluid film can crystallise and form solid deposits. The solid deposits can cause high back-pressure, material deterioration and ammonia slip. This project is done in collaboration with Scania CV AB. Scania is a world-leading manufacturer of heavy-duty vehicles, busses and engines. Scania works continuously to develop new simulation methods to capture the complex phenomena of AdBlue spray, wall film dynamics and risk of solid deposits, to use in the development process of new components. The aim of this project is to implement and evaluate a new method to predict the risk of crystallisation of urea (AdBlue) using the software Star-CCM+. Two different geometries are studied, a test rig and a Scania silencer. Different operating conditions, parameter settings and a speed-up method are analysed. During the project a base-line model has been created and the results have been compared with measurement results and the software AVL Fire. The results on the test rig show the effect of altering the mesh and important model parameters. Injected particles are grouped into parcels with the same properties. The number of parcels is a crucial factor for the wall film formation and should be sufficiently high to get a statistical representation of the droplet size distribution. The results from the real silencer show strong evaporation and thin wall film formation with the suggested method. The method is shown to be stable and the software is user-friendly. A speed-up method was investigated to decrease the computational time. The computational time was reduced by a factor 20. The outcome of this project is a guide for set-up of AdBlue spray and wall film simulations. Recommendations to future work includes further validation of the settings, investigation of the evaporation rate and droplet size distribution and the application to other cases. The next step is also to tune the critical thresholds for deposit risk assessment. / Lagstiftning har tvingat fordonstillverkare att minska avgasutsläppen. Luftföroreningen kväveoxid (NOX) har visat sig ha en negativ inverkan på människors hälsa och på miljön. En viktig teknik för att minska utsläppen av NOX ¨ar att implementera ett efterbehandlingssystem. Efterbehandlingssystemet tar hand om avgaserna genom substrat, filter och ett förångningssystem. I förångningssystemet sprutas en urea-vattenlösning, som kallas AdBlue, in i de heta avgaserna där den förångas till ammoniak NH3 och vatten H2O. Ammoniakgasen leds därefter in till SCR katalysatorn där den kemiskt reagerar med NOX och bildar kvävgas N2 och vattenånga. Problem kan uppstå om fel mängd AdBlue sprutas in, då kan vätska byggas upp på förångsningsytor, kristallisera och bilda avlagringar. Avlagringarna kan bygga upp en solid klump som kan orsaka ett högt mottryck, nedbrytning av material och ammoniakslip. Detta arbete är ett samarbete med Scania CV AB som är en världsledande producent av lastbilar, bussar och motorer. Scania arbetar kontinuerligt med att utveckla nya simuleringsvertyg för att beskriva uppkomsten av Urea avlagringar för att använda i utvecklingen av nya komponenter. Syftet med detta arbete är att implementera och utvärdera en ny metod för att prediktera klump mha simuleringsverktyget Star-CCM+. Två olika geometrier är använd i arbetet: en testrigg och en av Scanias ljuddämpare. Olika driftspunkter, parametrar och en uppsnabbad metod är studerade. Under projektets gång har en modell byggts upp och jämförts med mätningar och simuleringar från programvaran AVL Fire. Resultatet från simuleringarna på testriggen visar effekten av att variera olika parametrar. Partiklarna som sprutas in i systemet är grupperade i paket med liknande egenskaper. Antalet paket påverkar uppbyggnaden av väggfilm och det rekommenderas att denna parameter hålls hög för att statistiskt beskriva droppfördelningen av partiklar. Resultaten på ljuddämparen visar en stark förångning och en tunn väggfilm för samtliga driftspunkter. Den implementerade metoden har visat sig vara stabil och användarvänlig. En uppsnabbad metod har utvärderats för att minska beräkningstiden. Beräkningstiden kunde minskas med en faktor 20. Resultatet av arbetet är en guide för hur metoden implementeras och bör användas. Rekommendationer till framtida arbete är en fortsatt undersökning av parametrar, utvärdering av förångningsmodellen, validering av droppstorleksfördelningen och tillämpningen på andra geometrier. Nästa steg i utvecklingen skulle vara att kalibrera tröskelvärden för prediktering av klump.