Magister Chirurgiae Dentium (MChD) / Water-pipe tobacco smoking (WTS) is a form of tobacco use with different names. There is a misconception that passing tobacco smoke through water reduces its harmful effects to increase its popularity. One million individuals smoke water-pipe daily, resulting in approximately five million deaths per annum globally. The toxic effects of WTS are related to the several components of the tobacco mixture. WTS contains 100 times more tar, four-fold more nicotine, eleven-fold more Carbon Monoxide (CO), and two to five-fold more polycyclic aromatic hydrocarbons than cigarettes.

This project aimed to investigate the capability of the STAR CCM+ software when predicting the flow with particles using Lagrangian Particle Tracking and Discrete Element Method. The first part pertained to rectangular channel flow, with ratio between height of the channel and particle diameter (2h/Dp ) of 15. It was found out that simulations of particles in a channel come with many diculties. Such as, obtaining accurate pressure drop results using DEM when comparing to DNS simulations including particles within a reasonable computational time. The second part consisted of a simulation of the off-centred mixing tank. As the use of DEM caused numerical issues, another modeling approach was used. Therefore, the Lagrangian Particle Tracking was used. The outcome of the project is the sensitivity study of the forces which can be applied to the particles. The finding was that the Shear Lift force and the Virtual Mass force have a negligible contribution in regards to the particles distribution. In addition to this, it was also discovered that the turbulence model has a large effect on the particles in the near-wall region. Choosing an isotropic turbulence model resulted in clustering of the particles near the wall, therefore an anisotorpic turbulence model needed to be used.

The master’s thesis discusses siphon pipes that are used to collect groundwater. The goal of work is to define the most frequent undesired events that may appear on siphon pipes, and verifying the individual springs. The work is addressed in accordance with the metodology of risk analysis WaterRisk. The content of the work is a summary of the hydraulic of siphon pipes and their use in practice, hazard identification, defining the most frequent undesired events and consequences on siphon pipes, and their verification in the spring in a particular case study.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19288号 / 工博第4085号 / 新制||工||1630(附属図書館) / 32290 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 細田 尚, 教授 戸田 圭一, 教授 後藤 仁志 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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Under årens gång har regelverk och byggnormer ändrats, och det har även gjort att utformningen av dessa har påverkats. Utförandekrav har övergått till funktionskrav, vilket har gjort att säkerhetsrisker kan uppstå eftersom olika metoder används vid installation. Ett sådant exempel är risken för legionellatillväxt. För att minimera denna risk har Boverket tagit fram byggregler, däribland att tappkallvattentemperaturen inte får överstiga 24°C under en period på åtta timmar då vattnet är stillastående. Baserat på detta har Säker Vatten AB utvecklat branschregler för VVS-företag och har därmed upptäckt problem då tappkallvattenledningen ligger i ett golv med installerad golvvärme. På denna grund bygger detta arbete som genom simuleringar i Comsol Multiphysics® v. 5.4 undersöker fyra modeller av kallvattenrör i golv med golvvärme. Resultatet för de fyra modellerna visar att kallvattnets temperatur överstiger 24°C vid installation av golvvärme vid användning av smala vattenrör och tunn isolering. Vid undersökning av användning av grövre rör med tjockare isolering blev resultatet att en kombination av 20mm i diameter vattenrör och 80mm isolering respektive 25mm i diameter vattenrör och drygt 50mm isolering klarade Boverkets temperaturkrav. Det framtagna resultatet visar på att det krävs en stor isoleringstjocklek vilket kan göra kallvattenledningen för stor i jämförelse med golvets tjocklek och därmed riskeras golvets stabilitet. Därför kan det vara bättre att använda en annan placering av kallvattenledningen när golvvärme installerats. / Building regulations and standards have changed over the years which has also had an impact on their design. Performance standards have changed to functional standards, which has led to potential safety hazards, as different methods are used by different stakeholders during installation. An example of a potential safety hazard is legionella growth. To minimize this particular hazard, the Swedish Board of Housing, Building and Planning has developed building regulations, including the regulation that the temperature of cold tap water cannot exceed 24°C for a period of eight hours while the water is stagnant. Based on this regulation, Säker Vatten AB has developed a set of trade standards for plumbing companies and has discovered that problems arise when cold-water pipes are situated in floors with underfloor heating. Based on the above, this project studies four models of cold-water pipes situated in floors with underfloor heating through simulations in Comsol Multiphysics® v. 5.4. The results from the four models show that the cold-water temperature exceeds 24°C when underfloor heating is installed and narrow water pipes and thin insulation are used. When studying the use of pipes with larger diameters and thicker insulation, the results show that the combinations of a 20mm diameter pipe with 80mm insulation, and a 25mm diameter pipe with just over 50mm insulation, satisfied the temperature regulations required by the Swedish Board of Housing, Building and Planning. The results obtained show that thick insulation is necessary, which can cause the cold-water pipe to be too large in comparison with the floor’s thickness, risking the floor’s stability. As a result, alternative placement of the cold-water pipe is to is to be preferred when underfloor heating is installed.

I den här rapporten presenteras en konstruktion av en ny rörrensningsmaskin som beställts av ett företag verkande inom rörrensningsbranschen. Konstruktionen som togs fram har; en grund i plast, vilken kan formgjutas i ett stycke, en modul med alla komponenter samlade inne i rörrensningsmaskinens trumma, teleskophandtag som gör den lätt att förvara, samt förvaringsmöjligheter för extra tillbehör. Prestandan på maskinen har optimerats genom mätserier och beräkningar, vilket gett en optimal effekt, vikt och storlek. Rörrensningsmaskinen modellerades i Solid Edge, och vissa av delarna analyserades därefter i Ansys. Till rörrensningsmaskinens vajer konstruerades en växel som ska lösa problemen med vibrationer och värmeutveckling. En prototyptillverkning på denna växel gjordes för att testa om den löste problemen, vilket dock inte kommer att presenteras i denna rapport av konfidentiella skäl. / This report will present a design study of a new development of a pipe cleaning machine, which is ordered by a company working in the plumbing industry. The design that has been developed consists of; a base structure made in plastic material, which can be mold casted in one piece, a module that places all the components inside the drum, telescopic handles which make the machine easy to store, and storage locations for additional accessories. The performance of the machine has been optimized by test studies and calculations, which has given the optimal power, weight and dimensions. The pipe cleaning machine was modeled in Solid Edge, and then imported into Ansys for further calculations. To solve problems with vibrations and heat generations along the wire, a gear was designed. This gear was later manufactured and tested to be able to verify that the described problems were solved. This part is, however, not included in this report for reasons of confidentiality.