Modeling of airflow resistance in grain bulk requires knowledge of the tortuosity and velocity of the air flow through the grain bulk. In this study, experiments were carried out to determine these characteristics of airflow paths by analyzing digital images of smoke-visualized airflow paths inside a grain bulk obtained with a high speed camera. Colored smoke with approximately the same density as air was introduced into the test box for the visualization of the airflow through the grain bulk. Soybeans with a moisture content of 8.82% on wet basis were used in this study. The high quality videos obtained by recoding the fast movement of the smoke through the grain bulk was first separated into frames using a commercial software, VirtualDub (CRIM, Montreal, Québec, Canada), and the 512× 384 pixel RGB image files (frames) extracted from the recorded videos and read into ImageJ an image processing Java-based software developed by the United State National institute of Health, to track the movement of the smoke in the images, frame by frame to determine lengths, tortuosities of the different flow paths, as well as their velocities.

Modeling of airflow resistance in grain bulk requires knowledge of the tortuosity and velocity of the air flow through the grain bulk. In this study, experiments were carried out to determine these characteristics of airflow paths by analyzing digital images of smoke-visualized airflow paths inside a grain bulk obtained with a high speed camera. Colored smoke with approximately the same density as air was introduced into the test box for the visualization of the airflow through the grain bulk. Soybeans with a moisture content of 8.82% on wet basis were used in this study. The high quality videos obtained by recoding the fast movement of the smoke through the grain bulk was first separated into frames using a commercial software, VirtualDub (CRIM, Montreal, Québec, Canada), and the 512× 384 pixel RGB image files (frames) extracted from the recorded videos and read into ImageJ an image processing Java-based software developed by the United State National institute of Health, to track the movement of the smoke in the images, frame by frame to determine lengths, tortuosities of the different flow paths, as well as their velocities.

Within the company Infinera, there is a need for an improved thermal design of an existing chassis product for use in telecommunications for distribution of services within the Edge & Metro network. To enable an optimized airflow design of the chassis, there is a need of analyzingdifferent simulation cases performed in FloTHERM. Mechanical and electrical airflow design has been examined in different cases that cover the system requirements.Thermal analyzes of the product have been performed using the FloTHERM tool, and changes and improvements to the design have been performed via the CAD SolidWorks software tool.Problem formulation for this thesis is to further develop the design of the chassis for improved airflow for electrical and optical components that are placed in an existing chassis for the temperature range of 0-70 ℃ according to the industry standard NEBS (Level 3). The slot-in card has been analyzed in a worst-case scenario to identify the most critical components on the PCB board. The result that has been achieved is six different simulation cases with different airflow designs and models of fans that are adapted to today's existing chassis. An updated final version based on simulation results has been modeled as a proposal for the product in the CAD program. A 2D drawing of the design of the product is included as an appendix.The conclusion of this work has shown an improved airflow design on a chassis with a side-byside airflow configuration with the use of four replaceable fans within a fan bay. A bypass block ontop of the cover has shown good results as a cooling method on electrical and optical components. In this work, due to limited time, the bypass block has not been completed as a 3D modeling part. This will be continued as a suggested future work. In addition, a front-to-side airflow design has been analyzed in FloTHERM, this can also be further developed and investigated in more detail in future work for an optimized airflow design of the chassis.Keywords: Airflow systems for electronics, thermal management, telecommunication equipment, airflow resistance, cooling of electronics. Keywords: Airflow systems for electronics, thermal management, telecommunication equipment, airflow resistance, cooling of electronics. / Inom företaget Infinera finns det ett behov av en förbättrad termisk design av en existerande chassiprodukt för användning inom telekommunikation för distribution av tjänster inom Edge &Metro nätverk. För att kunna optimera luftflödet av chassit behövs termiska simuleringar utförastillsammans med mekaniska och elektroniska designflöden för att kunna undersöka luftflödet i olika situationer som täcker systemkraven. Termiska analyser på produkten har utförts genom simuleringsverktyget FloTHERM, samtförändringar och förbättringar av konstruktionen har utförts via programverktyget CAD SolidWorks. Problemformulering för det här examensarbetet är att vidareutveckla designen för chassit för ett förbättrat luftflöde för elektriska och optiska komponenter som placeras i ett existerande chassitför temperaturområdet 0–70 ℃. Samt att chassit förhåller sig till bransch standarden NEBS (Nivå 3) och analyseras i värsta utfallscenariot av ett slott-in kort.Det resultat som har uppnåtts är sex olika utfall av chassit med olika luftflödes design och modeller av fläktar som är anpassade för dagens chassiprodukt med uppföljda kravkriterier. En uppdaterad slutgiltig version baserat på simuleringsresultat har modellerats som förslag på produkten i CAD programmet. En 3D ritning på designen av produkten medföljs som bilaga. Slutsatsen för det här arbetet i syfte till ett förbättrad luftflödes design är ett chassi med en sida-tillsida luftflödes design med fyra utbytbara fläktar i ett utbytbart fläktpaket. Ett nedsänkt tak i chassit ovanför kortet har visat goda resultat som en kylningsmetod på elektriska och optiska komponenter. I detta arbete, på grund av begränsad tid, har ett nedsänkt tak inte fullföljts som en 3D modellering som en tillhörande del av chassit. Ett sänkt innertak kommer att behövaskompletteras i ett fortsatt arbete för framtiden. Även en luftflödesdesign som har undersökts framifrån-till-sida av chassit i FloTHERM kan vidareutvecklas och undersökas närmare i ett framtida arbete för en optimerad luftflödesdesign av chassi produkten. Nyckelord: Luftflödessystem för elektronik, termisk hantering, telekommunikations applikationer, luftflödesmotstånd, kylning av elektronik. Nyckelord: Luftflödessystem för elektronik, termisk hantering, telekommunikations applikationer, luftflödesmotstånd, kylning av elektronik