Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-04T05:25:21Z (GMT). No. of bitstreams: 1 Mesquita_AmirZacarias_D.pdf: 6016264 bytes, checksum: 00f6515432485b46007d7639b12802fc (MD5) Previous issue date: 2005 / Resumo: O Reator Nuclear de Pesquisa TRIGA IPR-RI completou em novembro de 2004, 44 anos de operação. Inicialmente sua potência máxima era de 30 kW térmicos, posteriormente acrescentaram-se mais elementos combustíveis ao núcleo aumentando a potência para 100 kW, sendo esta a atual potência licenciada. Novos combustíveis foram acrescentados recentemente permitindo que a potência atinja níveis de 250 kW. O TRIGA IPR-RI é um reator de piscina com o núcleo refrigerado por circulação natural. Apesar dos vários trabalhos de pesquisa realizados nesta instalação, notadamente em ativação neutrônica, existe uma carência de dados termo-hidráulicos teóricos e experimentais sobre seu funcionamento. Sendo assim rea1izou-se-se uma série de testes experimentais dando enfoque a medidas de temperatura no centro do elemento combustível, no núcleo e no poço, com o reator operando em vários níveis de potência. As experiências aqui relatadas fazem parte da programação de pesquisas do CDTN/CNEN, que têm como objetivo comissionar o Reator TRIGA IPR-RI para a operação rotineira a 250 kW. Este trabalho descreve os estudos analíticos e experimentais realizados com o intuito de determinar a distribuição das temperaturas no reator. Desenvolveu-se uma metodologia para a calibração e monitoração da potência dissipada pelo núcleo, implantando assim novos canais de medida de potência por processo térmico. A condutividade térmica do elemento combustível e o coeficiente de transferência de calor de seu revestimento para o refrigerante foram avaliados experimentalmente. Foi proposta uma formulação para a determinação do valor da condu1ância na interface entre combustível e seu revestimento (gap). Os resultados experimentais foram comparados com valores teóricos encontrados na literatura. Como subsídio às experiências, desenvolveu-se um sistema e um programa de coleta e processamento de dados para o reator, capaz de acompanhar em tempo real e registrar seus - principais parâmetros operacionais. As experiências realizadas permitiram uma melhor compreensão do comportamento termofluidodinâmico do reator, ajudando no aperfeiçoamento de sua modelagem e contribuindo para a sua segurança operacional / Abstract: The TRIGA-IPR-R1 Research Nuclear Reactor has completed 44 years in operation in November 2004. Its initial nominal thermal power was 30 kW. In 1979 its power was increased to 100 kW by adding new fuel elements to the reactor. Recently some more fuel elements were added to the core increasing the power to 250 kW. The TRIGA-IPR-R1 is a pool type reactor with a natural circulation core cooling system. Although the large number of experiments had been carried out with this reactor, mainly on neutron activation analysis, there is not many data on its thermal-hydraulics processes, whether experimental or theoretical 80 a number of experiments were carried out with the measurement of the temperature inside the fuel element, in the reactor core and along the reactor pool. During these experiments the reactor was set in many different power levels. These experiments are part of the CDTN/CNEN research program, and have the main objective of commissioning the 1RIGA-IPR-Rl reactor for routine operation at 250 kW. This work presents the experimental and theoretical analyses to determine the temperature distribution in the reactor. A methodology for the calibration and monitoring the reactor thermal power was also developed. This methodology allowed adding others power measuring channels to 1he reactor by using thermal processes. The fuel thermal conductivity and the heat transfer coefficient from the cladding to the coolant were also experimentatly valued. It was also presented a correlation for the gap conductance between the fuel and the cladding. The experimental results were compared with theoretical calculations and with data obtained from technical literature. A data acquisition and processing system and a software were developed to help the investigation. This system allows on line monitoring and registration of the main reactor operational parameters. The experiments have given better comprehension of the reactor thermal-fluid - dynamics and helped to develop numerical models, contributing to operational safety improvements / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

The current study is a part of a long term experimental project devoted to investigate flow boiling heat transfer, pressure drop and flow visualization of R134a in small to mini/micro-diameter tubes. The experimental facility was first designed and constructed by X. Huo (2005) with the contribution of L. Chen (2006). In the present study, the experimental facility was upgraded by changing the heating system from AC to DC heating and also upgrading the logging system through using a faster data logger and developing a new Labview program. The objectives of the current study include (i) contribute in identifying the reasons behind the wide scatter in the published flow boiling heat transfer results, (ii) contribute in understanding the fundamentals of flow boiling heat transfer in mini/micro-diameter tubes and (iii) evaluation of the existing heat transfer and pressure drop prediction methods. Two sizes of stainless steel tubes were investigated in the current study; 0.52 mm and 1.1 mm diameter. In the current study, the 0.52 mm tube was roughly called a “micro-tube” whilst the 1.1 mm tubes were called “mini-tubes”. The present study proposes two possible reasons for the scatter in the published heat transfer results. The first reason is the variations in the heated length from one study to another–there is no criterion for choosing the heated length. The second reason is the variations in the inner surface characteristics of the channels from one study to another. These two important parameters were not taken into consideration by researchers in the past studies. Accordingly, the effect of the heated length was investigated in the current study using a seamless cold drawn tube with diameter of 1.1 mm and heated length ranging from 150 to 450 mm. The effect of the tube inner surface was also tested here by conducting the test in two stainless steel tubes with diameter of 1.1 mm and manufactured by two different processes. The first tube was manufactured by welding technique whilst the second tube was a seamless cold drawn tube. Both tubes were identical in design and dimensions. The inner surface of each tube was examined first using SEM analysis and demonstrated that, the surface morphology is completely different. The local heat transfer coefficient was determined through measuring the local wall temperature using 14 K-type thermocouples attached to the wall using thermally conducting but electrically insulating epoxy supplied by Omega. Pressure drop was measured directly across the heated section and a high speed camera was used for the flow visualization at 1000 frames/s. All measurements were recorded after the system attained steady state. The experimental conditions include mass flux range of 100 – 500 kg/m2 s, system pressure range of 6 – 10 bar, inlet sub-cooling of about 5K and exit quality up to about 0.9. The most frequently observed flow regimes in the 0.52 mm tube were found to be slug (elongated bubble), transition to annular and annular flow regimes. In the 1.1 mm tube, the observed regimes were found to be slug, churn and annular. The transition from slug flow to annular flow in the 0.52 mm tube occurred smoothly with little disturbances at the liquid vapour interface compared to the 1.1 mm tube. Additionally, increasing the heated length of the 1.1 mm tube was found to shift the transition to annular flow to occur at lower vapour quality. The heat transfer results demonstrated that the behaviour of the local heat transfer coefficient in the 0.52 mm diameter tube is different compared to that in the 1.1 mm tubes. Also, the tube inner surface characteristics and the heated length were found to strongly influence the local behaviour of the heat transfer coefficient. Flow boiling hysteresis was investigated and the results indicated that hysteresis exists only at very low heat fluxes near the boiling incipience. Existing heat transfer and pressure drop correlations were examined using the results of the 0.52 and 1.1 mm seamless cold drawn tubes. The pressure drop data were predicted very well using the Muller-Stienhagen and Heck (1986) correlation, the homogeneous flow model and the correlation of Mishima and Hibiki (1996). On the contrary, all macro and microscale heat correlations failed to predict the current experimental data. The mechanistic models failed to predict the data of all tubes with the same accuracy. Accordingly, two heat transfer correlations were proposed in the current study. The first correlation is based on dimensionless groups whilst the second is based on the superposition model of Chen (1966). Both correlations predicted the current experimental data and the data of Huo (2005) and Shiferaw (2008) very well.

L'industrie automobile cherche à réduire son utilisation des liquides de coupe en usinage pour des raisons économiques, environnementales et sanitaires. Les fabricants développent ainsi la démarche Minimum Quantity Lubrication qui vise à réduire au strict minimum l'utilisation des liquides de coupes en usinage. En l'absence de liquide de coupe, la stabilisation thermique de la pièce n'est plus assurée et des échauffements locaux apparaissent. Ces échauffements créent des déformations qui doivent être quantifiés et pris en compte afin d'assurer la conformité de la géométrie produite.Une démarche de modélisation de l'échauffement d'une pièce pendant l'usinage est présentée. Le modèle obtenu permet à la fois de quantifier la quantité de chaleur introduit dans la pièce pour des usinages simples et de simuler les déformations d'une pièce complexe lors de l'enchainement d'opération d'usinage. Cette quantification repose sur une méthode inverse. Elle est appliquée à des opérations de fraisage, perçage et taraudage d'un alliage d'aluminium AS9U3. Dans un second temps, une étude de l'influence de l'ordonnancement des opérations d'usinage d'un carter de boite de vitesses automobile sur la qualité de la géométrie produite est conduite. Cette étude illustre l'intérêt du modèle de simulation et des outils développés pendant la thèse. Enfin, les enjeux économiques et environnementaux de la technologie MQL seront abordés. / The application of MQL or dry machining in mass production becomes more and more accepted. Dry (MQL) machining is a very efficient solution to reduce the usage of cutting fluids and represents an effective measure for an environmental friendly production. However, these techniques do not benefit any more from the stabilization in temperature obtained with cutting fluids. More important and more heterogeneous increases of the temperature are observed. This leads to distortions of the work piece during machining which are necessary to be taken into account to maintain the geometrical quality of the manufactured surfaces.A model of the warm-up of a part during machining is presented. The obtained model allows to quantify heat introduced into the work piece for simple operations and to feign the distortions of a complex part when operations are enchained. This quantification is based on an inverse method. It is applied for reaming, drilling and tapping process for an aluminum alloy AS9U3. Secondly, a study about influence of operations organization is done. We use the model to quantify distortions an aluminum clutch case along machining. This study illustrates interest of the model and of tools developed during the PhD. In a last part, economic and environmental stakes of the MQL approach are discussed.

Ce travail aborde la problématique des systèmes de refroidissement ou de contrôle thermique industriels. Nous avons particulièrement mis l'accent sur le refroidissement des serveurs informatiques. Une première partie consiste en l'étude des moyens d'amélioration des techniques de refroidissement existantes, tandis que la deuxième partie est une réflexion sur des techniques de refroidissement alternatives potentiellement plus efficaces et répondant aux demandes actuelles du contrôle thermique industriel. Dans le premier chapitre, nous analysons la bibliographie et la théorie relatives aux phénomènes physiques derrière les techniques de refroidissement étudiées. Ensuite, une classification des techniques de refroidissement est proposée en fin de chapitre. Ce chapitre a servi de base pour l'amélioration des technologies de refroidissement existantes et à la réflexion sur de nouvelles techniques plus efficaces. Le second chapitre porte sur l'optimisation d'une plaque froide, destinée au refroidissement des serveurs informatiques, en s'aidant d'un outil numérique et d'essais expérimentaux. Nous avons noté une augmentation des transferts de chaleur dans la plaque froide en utilisant des inserts, notamment ceux en forme de losange disposés en quinconce. A l'inverse, l'utilisation de certains nanofluides en tant que fluides caloporteurs ne semble pas apporter de gain significatif. Dans le troisième chapitre nous détaillons la démarche suivie pour la conception d'un dissipateur de chaleur basé sur une technologie caloducs, destiné au refroidissement des cartes électroniques. En premier lieu, nous présentons le modèle thermohydraulique de dimensionnement d'un caloduc cylindrique ; une étude paramétrique (géométrique, type de fluide,...) nous a permis d'identifier le jeu de paramètres donnant la meilleure performance du caloduc. En second lieu, nous évoquons les tests réalisés sur le dissipateur de chaleur à caloduc qui nous amènent à valider en partie le modèle thermohydraulique développé. Le dernier chapitre porte sur la réalisation et l'étude d'un démonstrateur pour le refroidissement des cartes électroniques par immersion dans un liquide à basse température de saturation. On commence par la mise en place et l'utilisation d'un modèle numérique pour la conception du démonstrateur, puis des tests expérimentaux sont réalisés. Les premiers résultats obtenus en utilisant le SES-36 comme fluide de travail sont assez prometteurs.Mots clés : modélisation, transfert de chaleur, refroidissement, datacenter, liquid-cooling, caloducs, échangeurs, nanofluides, ébullition en vase, simulation numérique / The present work is about industrial thermal control systems issues, a focus is done on IT servers cooling. The first part of this document is about cooling techniques optimization. The second part concerns investigations for new cooling techniques potentially more efficient and which can address today's challenges of industrial thermal control systems. In the first chapter, we have done a literature survey and a theoretical analysis of physical phenomena behind studied cooling techniques. Then, we have sorted those techniques according to some criteria. This chapter is a basis for optimization studies we have achieved in the second chapter and for our new cooling techniques investigations in the two last chapters. In the second chapter, we have presented a study about heat transfer enhancement in a cold plate developed for IT servers liquid-cooling. We have observed great heat transfer enhancement when adding lozenge shaped fins inside the cold plate channels. No gain was noted when using some nanofluids as heat transfer liquids. We have shown, in the third chapter, a conception algorithm of a heat spreading device destined for IT servers cooling. The heat spreader is based on a heatpipe technology. First of all, we have presented the thermohydraulic model for cylindrical heatpipes design. A parametric study (geometric, working fluids ...) showed the best combination to obtain the highest heatpipe performance. Then, the heat spreader has been tested and we have validated partially the heatpipe model. The last chapter of this work is a study of a demonstrator destined for cooling down electronic components by immersion in a dielectric fluid with a low saturation temperature. We first built a numerical model to design the demonstrator and then it has been tested. The first results are very encouraging, when using SES-36 as a working fluid.Keywords : modeling, heat transfer, cooling, datacenter, liquid-cooling, heat pipes, heat exchangers, nanofluids, pool boiling, numerical simulation

Les fluctuations thermiques présentes dans les tés de mélange provoquent des contraintes thermiques qui peuvent mener à l'apparition de fissures qui se propagent plus ou moins rapidement dans la structure. Une possibilité pour réduire ces risques est d'installer des mélangeurs statiques (statics mixers) pour accroître le mélange. Une telle technologie a été utilisée par Utveckling AB depuis 1980 dans des installations nucléaires. Toutefois, ces technologies sont très coûteuses. C'est pour cette raison que plusieurs investigations numériques ont été faites pour prédire les fluctuations de température causées par le mélange turbulent dans cette configuration d'écoulement. On effectue la simulation numérique de l'écoulement sur deux types de té de mélange. L'un avec des bords droits et une paroi en Plexiglas, et l'autre avec des bords arrondis et une paroi en inox 304L. Dans le premier cas la condition de paroi est adiabatique et dans le second cas on effectue un couplage entre le code CFD (Computational Fluid Dynamic) Code_Saturne et le code SYRTHES pour l'analyse de la température dans le solide. L'apport principal de la thèse est la détermination des statistiques temporelles d'ordre élevé dans une configuration aussi complexe. En effet, les équations de transport de l'énergie cinétique turbulente, de la variance de la température et des flux thermiques turbulents sont déterminées dans les deux configurations (adiabatique et avec des parois en inox), ce qui montre l'influence de la paroi sur le transfert de chaleur en région proche paroi. / Thermal fluctuations present in mixing tees cause thermal stresses that can lead to the appearation of cracks, which spread more or less quickly in the structure. One possibility to reduce these risks is to set static mixers (statics mixers) to increase the mixture. Such technology has been used by Utveckling AB since 1980 in nuclear installations. However, these technologies are very expensive. It is for this reason that many numerical investigations have been made to predict temperature fluctuations caused by turbulent mixing in this configuration flow. The resolution of the conservation equations is made with a finite volume approach using large eddy simulation or LES . The subgrid models used are Smagorinsky, WALE (Wall Adapted Local Eddy) and dynamic Smagorinsky. The SGDH model (Simple Gradient Di? Usion Hypothesis) is used for modeling greeting thermal subgrid and the turbulent Prandtl number is fixed one. Generation turbulence input field is made using the SEM method (Synthetic Eddy Method). The main contribution of this thesis is the determination of time turbulent statistic in a complex configuration. Indeed, the transport equations of turbulent kinetic energy, temperature variance and turbulent heat flux are determined in both configurations (adiabatic walls and stainless steel), which shows the influence of the wall on heat transfer in near-wall region.

Le projet porte sur le développement d'une pompe à chaleur magnétocalorique pour l'entreprise NextPAC. Une étude a été réalisée sur les transferts thermiques se déroulant dans le régénérateur de la pompe. Cette étude a permis de développer un modèle numérique permettant de simuler les échanges thermiques au sein du régénérateur et de développer un démonstrateur afin de pouvoir réaliser des mesures thermiques sur un matériau magnétocalorique échangeant avec un fluide caloporteur en écoulement alterné. De plus, une étude critique et approfondie a été réalisée sur le premier prototype de NextPAC afin d'évaluer son bon fonctionnement. De nombreuses propositions d'amélioration ont été proposées pour la réalisation d'un second prototype. / The project involves the development of a magnetocaloric heat pump for the NextPAC company. A study has been realized on the thermal transfers in the pump's regenerator. This study allowed us to develop a digital model that simulates the thermal exchanges in the regeneratot and to develop a demonstrator in order to collect thermal measurements of a magnetocaloric material. This last exchanges heat transfers with an oscillating fluid flow. Moreover, a study on a first industrial prototype hads been carry out in order to check and to show improvements that have to be carry out fo a second planned prototype.

[pt] Os coeficientes de transferência de calor e os dados de perda de carga foram determinados experimentalmente, para o escoamento turbulento, em dutos circulares providos internamente de anéis transversais. Os resultados foram obtidos tanto para a região de entrada como na região totalmente desenvolvida. Foram investigados os efeitos da altura do anel, do espaçamento entre os anéis e do número de Reynolds. Variou-se o número de Reynolds de 5.000 a 75.000, enquanto que a faixa de passo p/H foi de 4 a 15. Duas alturas do anel foram estudadas, a saber, 0,05 e 0,10 vezes o diâmetro interno do tubo. O fator de atrito para as geometrias periódicas mostrou ser sempre bem superior ao fator de atrito para o tubo liso, crescendo rapidamente com H/D. Para os tubos com anéis de pequena altura, o fator de atrito decresce com o aumento do passo, enquanto o oposto é observado para os tubos com anéis maiores, na faixa pesquisada. Para H/D = 0,05, o coeficiente de transferência de calor é máximo para valores de p/H em torno de 10 e para baixos números de Reynolds. Para H/D e 0,10, o maior coeficiente de transferência de calor medido foi para p/H = 10, que mostrou ser praticamente independente do número de Reynolds. Uma comparação de desempenho entre os tubos anelados e liso foi realizada sob dois tipos de restrições, a saber, a iguais vazões mássicas e iguais potências de bombeamento. Os tubos anelados mostraram um melhor desempenho em todos os casos pesquisados, exceto para H/D = 0,10 com Re > 60.000. / [en] Heat transfer coefficients and pressure drop data were determine experimentally for turbulent flow in circular ducts equipped with internal transverse ribs. Both fully developed and entrance region results were obtained. The effects of the rib height, rib spacing, and Reynolds number were investigated. The Reynolds number ranged from 5,000 to 75,000, whereas the pitch p/H was varied in the range 4 to 15. Two rib heights were investigated, namely, 0.05 e 0,10 times the tube inside diameter. The friction factor for the periodic geometric was found to be always much larger than the smooth tube friction factor, increasing rapidly with H/D. For the tubes with short ribs, the friction factor decreases with increasing pitch, but the opposite is true for the tall ribbed tubes in the range investigated. For H/D = 0.05, tha heat transfer coefficient is highest for values of p/H around 10 and low Reynolds number. For H/D = 0,10, the highest heat transfer coefficients measured were for p/H = 10, where it was found to be nearly independent of the Reynolds number. Performance comparisons between the ribbed and smooth tubes were made under two types of constraints, namely, equal mass flow rate and equal pump power. It was found that the ribbed tubes have higher heat transfer perFormance for all cases investigated, except for H/D = 0.10 with Re > 60,000.

This experimental research aims at investigating the single-phase flow heat transfer and friction factor, flow boiling heat transfer and pressure drop, and flow visualisation in microchannels using de-ionized water. In the literature, many studies failed to explain the effect of aspect ratio on the single-phase and two-phase flow heat transfer rate and pressure drop. Because the channel aspect ratios and hydraulic diameters were varied together in those studies. Also, there is a discrepancy between past studies and the conventional theory for the flow boiling heat transfer characteristics. Accordingly, the objectives of this research can be listed as follows: (i) modifying the existing experimental facility to perform single-phase and two-phase flow heat transfer and pressure drop and two-phase flow pattern visualization experiments in microchannels, (ii) clarifying the fundamental aspects of flow boiling in micro passages, (iii) investigating the aspect ratio, heat flux, mass flux and vapour quality effects on flow patterns, heat transfer rate and pressure drop in single-phase and two-phase flow, (iv) comparing the obtained results with heat transfer and pressure drop correlations and flow pattern maps available in the literature. Consequently, the pre-existing experimental facility was modified in the current research by changing the pre-heaters, flowmeter and piping in order to achieve the goals of this study. Four copper rectangular microchannels were designed and manufactured. Three microchannel test sections having the same hydraulic diameter and length but different aspect ratios were investigated to reveal the effect of aspect ratio on the single-phase and two-phase flow heat transfer rate and pressure drop. The surface roughness of each microchannel was also examined. It was found that the surface roughnesses of all microchannels are similar. Moreover, an additional microchannel test section was used to examine the effect of heated length on the flow boiling heat transfer coefficient and pressure drop. The single-phase flow results demonstrated that the channel aspect ratio has no influence on the friction factor and heat transfer rate for the tested microchannels and experimental range. In the flow boiling experiments, bubbly, bubbly/slug, slug, churn and annular flow regimes were observed in the tested microchannels. The channel aspect ratio effect was found to be small on the observed flow patterns. The experimental flow patterns were predicted well by the flow pattern map proposed by Galvis and Culham (2012) except for the slug flow regime. The flow pattern maps of Sobierska et al. (2006) and Harirchian and Garimella (2009) reasonably predicted the experimental flow pattern data. The flow boiling heat transfer results showed that the prevailing heat transfer mechanism is nucleate boiling for the low and medium heat flux inputs. On the other hand, the dominant heat transfer mechanism is unclear at the high heat flux inputs while smaller aspect ratio microchannel has better heat transfer performance for low and medium heat flux inputs. However, at high heat flux inputs the channel aspect ratio effect was found to be insignificant on the flow boiling heat transfer coefficient. The experimental flow boiling heat transfer coefficient data were reasonably predicted by the correlations of Sun and Mishima (2009), Li and Wu (2010) and Mahmoud and Karayiannis (2011) from the literature. The flow boiling pressure drop characteristics were also examined in the tested microchannels. Outcome of the experiments consistently indicated a highly linear trend between the increasing flow boiling pressure drop and the heat and mass flux. Also, the flow boiling pressure drop increased with the increase in vapour quality. The effect of channel aspect ratio on the flow boiling pressure drop was also assessed. It was found that when the channel aspect ratio decreased, the flow boiling pressure drop increased. The experimental flow boiling pressure drop data were compared to correlations from the literature. Mishima and Hibiki (1996), Yu et al. (2002) and Zhang et al. (2010) correlations reasonably predicted the experimental flow boiling pressure drop results.

Additive manufacturing involves the layer-wise patterned addition of material to create 3D parts, allowing for parts with complex geometries that traditional subtractive manufacturing processes cannot create, while offering good value for low run production parts by eliminating the cost of tooling. Large Area Sintering is a form of powder based additive manufacturing where entire layer cross sections are heated and fused in a single continuous exposure process. This layer by layer powder sintering process is similar to selective laser sintering, but by heating the cross section at a slower and controllable rate there is an opportunity to achieve tighter control over thermal history. This thesis discusses the design, construction, and validation of a large area sintering test platform, as well as a preliminary study on feature resolution. A key component of this system was the integration of an infrared camera, allowing point-wise temperature control of the sintering cross section. There is a hypothesis that longer and controlled heating rates in Large Area Sintering (in comparison to Selective Laser Sintering) would allow the capability to process a wider range of materials, and give more control over the resulting final part properties. The test platform created a repeatable test environment, and successfully demonstrated the capability for point wise temperature control of the sintering cross section, enabling the ability to examine the effects of slower controlled heating rates. Available power on the system was 2.22 W/cm2 for heating, with a temperature control loop time of 160 – 180 ms. The results of the preliminary study on feature resolution also suggested a positive correlation between point wise closed loop temperature control and improved feature resolution, giving motivation for further study.

Sebastian Zetterström, Master of Science in energy systems, Mälardalens University in Västerås. Abstract of Master’s thesis, submitted 16th of August. Evaluation of a suction pyrometer by heat and mass transfer methods. The aim of the thesis is to evaluate the cooling of a specific suction pyrometer which is designed by Jan Skvaril, doctorate at Mälardalens University. First part is explained how the balances and correlations are performed before being implemented in MATLAB, after this  a ANSYS Fluent model is constructed and explained, which is used for the comparison of results. The cooling is performed by using water at an inlet temperature of 10°C and an assumed flue gas temperature of 810°C. Sensitivity analysis are performed to test the stability of the models which yield good results for stability, done by adjusting both flue gas temperature and inlet cooling water temperature which are as well presented for observation. From doing further MATLAB sensitivity analysis which show that the model still performs well and is stable. The resulting cooling water is heated to approximately 24, 8°C and the flue gas is cooled to 22, 4°C, in ANSYS Fluent the answer differs approximately 2°C and results in 20, 4°C which can be considered by looking at the flue gas inlet temperature of 810°C that this can be deemed an insignificant change and can therefore conclude that the comparison between the two platforms match each other good and that calculations can be considered accurate. Keywords:  Suction pyrometer, cooling, heat transfer, thermal resistance network, MATLAB, ANSYS Fluent, simulation