Syftet med detta arbete är att simulera ett värmesystem i COMSOL Multiphysics, Pipe Flow Module, Non-Isothermal Pipe Flow som innehåller ekvationer och randvillkor för att modellera inkompressibel strömning och värmeöverföring i rör. Data om processen och dess komponenter har samlats in från industrin där arbetet är utfört och i vissa fall modifierats för att bättre beskrivas i programmet. Utifrån insamlad data har en modell byggts upp och två simuleringar har gjorts. En stationär för starten av systemet, den har sedan legat till grund för en dynamisk som simulerar förloppet från start till normaldrift. Tiden det tar för det aktuella fallet att nå drifttemperatur är 16 timmar. En felströmning upptäcktes samt att en av pumparna inte kommer att klara en start från 20 °C.

<p> </p><p>The cooling system of a DC-motor is examined in this thesis. A change of direction of the cooling air is desired to prevent the generated coal dust from entering into the windings of the machine. Ultimately this will have a negative effect on the cooling in the machine and the loss of cooling needs to be compensated through other ways. The purpose of this thesis is to work for an improved operational safety and performance of the DC-motor and to make it more competitive in the market. By modelling the interior geometry of the machine and defining the boundaries in the software programs Gambit and FLUENT respectively, the motion and the heat transfer of the airflow could be simulated. The simulation results would give us an understanding of the flow pattern which later could be used to develop design modifications on the cooling system of a DC-motor. In this thesis the main focus lies on creating a simulation model with a sufficiently fine mesh size.</p>

<p>The objective of this thesis work was to construct and implement an algorithm into the programADAPDT to calculate the zero-lift drag profile for defined aircraft geometries. ADAPDT, shortfor AeroDynamic Analysis and Preliminary Design Tool, is a program that calculates forces andmoments about a flat plate geometry based on potential flow theory. Zero-lift drag will becalculated by means of different hand-book methods found suitable for the objective andapplicable to the geometry definition that ADAPDT utilizes.</p><p>Drag has two main sources of origin: friction and pressure distribution, all drag acting on theaircraft can be traced back to one of these two physical phenomena. In aviation drag is dividedinto induced drag that depends on the lift produced and zero-lift drag that depends on the geometry of the aircraft.</p><p>How reliable and accurate the zero-lift drag computations are depends on the geometry data thatcan be extracted and used. ADAPDT‟s geometry definition is limited to flat plate geometrieshowever although simple it has the potential to provide a huge amount of data and also delivergood results for the intended use. The flat plate representation of the geometry proved to beleast sufficient for the body while wing elements could be described with much more accuracy.</p><p>Different empirical hand-book methods were used to create the zero-lift drag algorithm. Whenchoosing equations and formulas, great care had to be taken as to what input was required sothat ADAPDT could provide the corresponding output. At the same time the equations shouldnot be so basic that level of accuracy would be compromised beyond what should be expectedfrom the intended use.</p><p>Finally, four well known aircraft configurations, with available zero-lift drag data, weremodeled with ADAPDT‟s flat plate geometry in order to validate, verify and evaluate the zeroliftdrag algorithm‟s magnitude of reliability. The results for conventional aircraft geometriesprovided a relative error within 0-15 % of the reference data given in the speed range of zero toMach 1.2. While for an aircraft with more complicated body geometry the error could go up to40 % in the same speed regime. But even though the limited geometry is grounds foruncertainties the final product provides ADAPDT with very good zero-lift drag estimationcapability earlier not available. A capability that overtime as ADAPDT continues to evolve hasthe potential to further develop in terms of improved accuracy.</p> / <p>Målet med detta examensarbete var att skapa och implementera en algoritm som införmöjligheten att beräkna nollmotstånd för givna flygplansgeometrier i programmet ADAPDT.ADAPDT, kort för AeroDynamic Analysis and Preliminary Design Tool, är ett program som,baserat på potential strömnings teori, beräknar krafter och moment på en geometri uppbyggd avplana plattor. Nollmotståndet kommer att baseras en kombination av handboksmetoder somfunnits lämpliga och applicerbara på geometridefinitionen given i ADAPDT.</p><p>Motstånd har sitt ursprung i två fysikaliska fenomen: friktion och tryckfördelning, ur vilka alltmotstånd som agerar på ett flygplan härrör. Inom flyget delar man in motståndet ilyftkraftsberoende inducerat motstånd samt geometriberoende nollmotstånd.</p><p>Hur pålitliga och noggranna motståndsberäkningarna kan förväntas vara beror på mängdengeometriska data som finns att tillgå. ADAPDT:s geometridefinition är begränsad till planaplattor men trots detta finns potential att leverera stora mängder data och resultat med rimlignoggrannhet. Plan plattgeometrin visade sig, för kroppsgeometrin, väldigt begränsad ochotillräcklig medan ving element kunde beskrivas med större noggrannhet.</p><p>En rad olika empiriska handboksmetoder användes för att skapa nollmotståndsalgoritmen. Vidvalet av formler och ekvationer var det viktigt att välja sådana som ADAPDT kunde försetillräckligt med data till. Samtidigt fick formlerna inte vara alltför simpla så att måttet avnoggrannhet i resultaten vart alltför låg mot för vad som, för ändamålet, är förväntat.</p><p>Slutligen valdes fyra kända flygplan, med nollmotståndsdata tillgängligt, att modeleras medADAPDT:s plan plattgeometri för att validera, verifiera och utvärdera algoritmens mått avtillförlitlighet. Resultaten för mer konventionella flygplanskonfigurationer visade på ett relativtfel mellan 0-15 % mot de givna referensflygplanens nollmotståndsdata inom hastigheterna 0 tillMach 1,2. För mer komplicerade konfigurationer steg det relativa felet omedelbart upp mot 40% inom samma hastighetsregim. Men även om den begränsade geometridefinitionen iADAPDT är grunden för mycket osäkerheter förser den slutliga produkten ändå programmetmed en väldigt god möjlighet till skattning av nollmotståndet som inte tidigare fanns. Enmöjlighet som över tid, allteftersom ADAPDT forstätter att utvecklas, har all potential till attförbättras med avseende på noggrannhet och tillförlitlighet.</p>

<p>In modern gas turbines parts of combustion chamber and turbine section are under heavy heat load, for example, the rotor inlet temperature is far higher than the melting point of the rotor blade material. These high temperatures causes thermal stresses in the material, therefore it is very important to cool the components for safe operation and to achieve desired component life. But on the other hand the cooling reduces the turbine efficiency, for that reason it is vital to understand and optimize the cooling technique.</p><p>In this project Thermochromic Liquid Crystals (TLCs) are used to measure distribution of heat transfer coefficient over a scaled up combustor liner section. TLCs change their color with the variation of temperature in a particular temperature range. The color-temperature change relation of a TLC is sharp and precise; therefore TLCs are used to measure surface temperature by painting the TLC over a test surface. This method is called Liquid Crystal Thermography (LCT). LCT is getting popular in industry due to its high-resolution results, repeatability and ease of use.</p><p>Test model in present study consists of two plates, target plate and impingement plate. Cooling of the target plate is achieved by impingement of air coming through holes in the impingement plate. The downstream surface of the impingement plate is then cooled by cross flow and re-impingement of the coolant air.</p><p>Heat transfer on the target plate is not uniform; areas under the jet which are called stagnation points have high heat transfer as compare to the areas away from the center of jet. It is almost the same situation for the impingement plate but the location of stagnation point is different. A transient technique is used to measure this non-uniform heat transfer distribution. It is assumed that the plates are semi-infinitely thick and there is no lateral heat transfer in the plates. To fulfill the assumptions a calculated time limit is followed and the test plates are made of Plexiglas which has very low thermal conductivity.</p><p>The transient technique requires a step-change in the mainstream temperature of the test section. However, in practical a delayed increase in mainstream temperature is attained. This issue is dealt by applying Duhamel’s theorem on the step-change heat transfer equation. MATLAB is used to get the Hue data of the recorded video frames and calculate the time taken for each pixel to reach a predefined surface temperature. Having all temperatures and time values the heat transfer equation is iteratively solved to get the value of heat transfer coefficient of each and every pixel of the test surface.</p><p>In total fifteen tests are conducted with different Reynolds number and different jet-to-target plate distances. It is concluded that for both the target and impingement plates, a high Reynolds number provides better overall heat transfer and increase in jet-to-target distance</p><p>decreases the overall heat transfer.</p>

<p>A first part of a ”Heat Transfer Handbook” about correlations for internal cooling of gas turbine vanes and blades has been created. The work is based on the cooling of vanes and blades 1 and 2 on different Siemens Gas Turbines. The cooling methods increase the heat transfer in the cooling channels by increasing the heat transfer coefficient and/or increasing the heat transfer surface area. The penalty paid for the increased heat transfer is higher pressure losses.</p><p>Three cooling methods, called rib turbulated cooling, matrix cooling and impingement cooling were investigated. Rib turbulated cooling and impingement cooling are typically used in the leading edge or mid region of the airfoil and matrix cooling is mostly applied in the trailing edge region.</p><p>Literature studies for each cooling method, covering both open literature and internal reports, were carried out in order to find correlations developed from tests. The correlations were compared and analyzed with focus on suitability for use in turbine conditions. The analysis resulted in recommendations about what correlations to use for each cooling method.</p><p>For rib turbulated cooling in square or rectangular ducts, four correlations developed by Han and his co-workers [3.5], [3.8], [3.9] and [3.6] are recommended, each valid for different channel and rib geometries. For U-shaped channels, correlations of Nagoga [3.4] are recommended.</p><p>Matrix cooling is relatively unknown in west, but has been used for many years in the former Soviet Union. Therefore available information in open literature is limited. Only one source of correlations was found. The correlations were developed by Nagoga [4.2] and are valid for closed matrixes. Siemens Gas Turbines are cooled with open matrixes, why further work with developing correlations is needed.</p><p>For impingement cooling on a flat target plate, a correlation of Florschuetz et al. [5.7] is recommended for inline impingement arrays. For staggered arrays, both the correlations of Florschuetz et al. [5.7] and Höglund [5.8] are suitable. The correlations for impingement on curved target plate gave very different results. The correlation of Nagoga is recommended, but it is also advised to consult the other correlations when calculating heat transfer for a specific case.</p><p>Another part of the work has been to investigate the codes of two heat transfer programs named Q3D and Multipass, used in the Siemens offices in Finspång and Lincoln, respectively. Certain changes in the code are recommended.</p>

<p>The thesis investigates if it is possible to replace several pumpimpellers with one controllable pumpimpeller, with a economical and a manufacturing analisys aspect. The studied pumpimpeller is mounted on a midrange wastewaterpump, N3127MT.</p><p>In the thesis a contemplated manufacturing process is evaluated for a concept that are supposed to act as a controllable pumpimpeller. The pumpimpeller are studied in a manufacturing and flow matter and are presented in the thesis.</p><p>The manufacturing cost is also estimated, and this has been compared to the storage cost and other costs that the existing pumpimpeller generates.</p><p>The thesis also shows that the concept has minor losses in cutting quality aswell as the effiency comparing to the existing pumpimpeller.</p><p>The concept also raises the manufacturing cost and this increasing cost makes the presented concept to expensive to carry through.</p><p>An investigation of the costs that the existing pumpimpeller produces has also been done, and this shows that there is not that much expenses to earn regarding to for example the storage cost. The storage cost includes information from Flygt’s central storagecenter in Lindas, Sweden and Metz, France, and also an inventory about the pumpimpellers located at Flygt’s different distributors worldwide.</p><p>The thesis shows that a controllable pumpimpeller will generally increase the cost for the pumpimpeller and the performance of the pumpimpeller will decrease.</p>

<p>The purpose of this thesis for Sapa Heat Transfer is to examine a furnace in which aluminium is pre-heated before hot rolling. The project is modeled in a computer environment in which the air flow in the furnace and the heat transfer to the aluminium solids are included. The computer environment and its governing equations, as well as boundary conditions and generalizations, are presented and explained.</p><p>The simulations are based on two models. The first model has an asymmetric solid placement, which is how it looks in today's ovens. It is validated against collected data. The second model has a symmetric solid placement, in which improvements are introduced and evaluated.</p><p>The results indicate that a symmetric positioning of metal solids in the oven is preferable in order to achieve a good airflow distribution. The use of plates has been proven useful for steering the air to critial areas and to get an even distribution of the airflow. Lastly the simulations indicate that an increased airflow can compensate the less optimal flow distribution that arises with asymmetric solid placements.</p>

<p>The development process for new aircraft configurations needs to be more efficient in terms of performance, cost and time to market. The potential to influence these factors is highest in early design phases. Thus, high confidence must be established in the product earlier than today. To accomplish this, the concept of virtual product development needs to be established. This implies having a mathematical representation of the product and its associated properties and functions, often obtained through numerical simulations. Building confidence in the product early in the development process through simulations postpones expensive testing and verification to later development stages when the design is more mature.</p><p>To use this in aerodynamic design will mean introducing more advanced physical modelling of the flow as well as significantly reducing the turn around time for flow solutions.</p><p>This work describes the benefit of using parallel computers for flow simulations in the aircraft design process. Reduced turn around time for flow simulations is a prerequisite for non-linear flow modelling in early design stages and a condition for introducing high-end turbulence models and unsteady simulations in later stages of the aircraft design process. The outcome also demonstrates the importance of bridging the gap between the research community and industrial applications.</p><p>The computer platforms are very important to reduce the turn around time for flow simulations. With the recent popularity of Linux–clusters it is now possible to design cost efficient systems for a specific application. Two flow solvers are investigated for parallel</p><p>performance on various clusters. Hardware and software factors influencing the efficiency are analyzed and recommendations are made for cost efficiency and peak performance.</p> / Report code: LiU-TEK-LIC-2006:27.

<p>When designing a new fuel management system for a spark ignition engine the amount of air that is fed to the cylinders is highly important. A tool that is being used to improve the performance and reduce emission levels is engine modeling were a fuel management system can be tested and designed in a computer environment thus saving valuable setup time in an engine test cell. One important part of the modeling is the throttle which regulates the air. The current isentropic model has been investigated in this report. A throttle body and intake manifold has been simulated using Computational Fluid Dynamics (CFD) and the influence of surface heating and surface wall roughness has been calculated. A method to calculate the effective flow area has been constructed and tested by simulating at two different throttle plate angles and several pressure ratios across the throttle plate. The results show that both surface wall roughness and wall heating will reduce the mass flow rate compared to a smooth and adiabatic wall respectively. The reduction is both dependent on pressure ratio and throttle plate angle. The effective area has showed to follow the same behaviour as the mass flow rate for the larger simulated throttle plate angle 31 degrees, i.e. an increase as the pressure drop over the throttle plate becomes larger. At the smaller throttle plate angle 21 degrees, the behaviour is completely different and a reduction of the effective area can be seen for the highest pressure drop where a increase is expected.</p> / <p>När ett nytt bränslesystem ska designas till en bensinmotor är det viktigt att veta hur stor mängd luft som hamnar i cylindrarna. Ett verktyg som är på frammarsch för att förbättra prestanda och minska emissioner är modellbaserad simulering. Med hjälp av detta kan ett bränslesystem designas och testas i datormiljö och därigenom spara dyrbar tid som annars måste tillbringas i en motortestcell. En viktig del av denna modellering är spjället eller trotteln vilken reglerar luften. I denna rapport har studier gjort på den nuvarande isentropiska modellen. Ett spjällhus och insugsgrenrör har simulerats med hjälp av Computational Fluid Dynamics (CFD) och påverkan av värme samt ytjämnhet på väggen har beräknats. En metod att beräkna den effektiva genomströmmade arean har konstruerats och testats vid två olika spjällvinklar samt flertalet tryckkvoter över spjället. Resultaten visar att både en uppvärmd vägg och en vägg med skrovlighet kommer att minska massflödet jämfört med en adiabatisk respektive en slät vägg. Minskningen har både spjällvinkel samt tryckkvots beroende. Den effektiva genomströmmade arean har visats sig följa samma beteende som massflödet vid den större simulerade spjällvinkeln 31 grader, det vill säga öka med ökat tryckfall över spjället. Vid den mindre vinkeln 21 grader, är beteendet helt annorlunda jämfört med massflödet och en minskning av den effektiva arean kan ses vid det största tryckfallet där en ökning förväntades.</p>

Numerical simulations of the Navier-Stokes equations are performed to achieve a better understanding of the behaviour of wakes generated by wind turbines. The simulations are performed by combining the in-house developed computer code EllipSys3D with the actuator line and disc methodologies. In the actuator line and disc methods the blades are represented by a line or a disc on which body forces representing the loading are introduced. The body forces are determined by computing local angles of attack and using tabulated aerofoil coefficients. The advantage of using the actuator disc technique is that it is not necessary to resolve blade boundary layers. Instead the computational resources are devoted to simulating the dynamics of the flow structures. In the present study both the actuator line and disc methods are used. Between approximately six to fourteen million mesh points are used to resolve the wake structure in a range from a single turbine wake to wake interaction in a farm containing 80 turbines. These 80 turbines are however represented by 20 actuator discs due to periodicity because of numerical limitations. In step one of this project the objective was to find a numerical method suitable to study both the flow structures in the wake behind a single wind turbine and to simulate complicated interaction between a number of turbines. The study resulted in an increased comprehension of basic flow features in the wake, but more importantly in the use of a numerical method very suitable for the upcoming purpose. The second objective of the project was to study the basic mechanisms controlling the length of the wake to obtain better understanding of the stability properties of wakes generated by wind turbine rotors. The numerical model was based on large eddy simulations of the Navier-Stokes equations using the actuator line method to generate the wake and the tip vortices. To determine critical frequencies the flow is disturbed by inserting a harmonic perturbation. The results showed that instability is dispersive and that growth occurs only for specific frequencies and mode types. The study also provides evidence of a relationship between the turbulence intensity and the length of the wake. The relationship however needs to be calibrated with measurements. In the last project objective, full wake interaction in large wind turbine farms was studied and verified to measurements. Large eddy simulations of the Navier-Stokes equations are performed to simulate the Horns Rev off-shore wind farm 15 km outside the Danish west coast. The aim is to achieve a better understanding of the wake interaction inside the farm. The simulations are performed by using the actuator disc methodology. Approximately 13.6 million mesh points are used to resolve the wake structure in the park containing 80 turbines. Since it is not possible to simulate all turbines, the 2 central columns of turbines have been simulated with periodic boundary conditions. This corresponds to an infinitely wide farm with 10 turbines in downstream direction. Simulations were performed within plus/minus 15 degrees of the turbine alignment. The infinitely wide farm approximation is thus reasonable. The results from the CFD simulations are evaluated and the downstream evolution of the velocity field is depicted. Special interest is given to what extent production is dependent on the inflow angle and turbulence level. The study shows that the applied method captures the main production variation within the wind farm. The result further demonstrates that levels of production correlate well with measurements. However, in some cases the variation of the measurement data is caused by the different measurement conditions during different inflow angles. / QC 20100720