Aggressive demands for high power density and low-cost power modules in the automotive sector pose significant challenges to the thermal management systems. These challenges necessitate adopting highly effective cooling technologies in power modules to remain competitive in the semiconductor industry. Furthermore, the thermal management strategy must be simple, easy to integrate, compact, effective, efficient, reliable, and economical. This thesis is an effort to investigate the impact of fin geometry on the overall performance of finned-type liquid-cooled power electronic modules in electrified transportation. The cooling system's performance metrics, including thermal resistance, pressure drop, pumping power, and mass, are discussed in depth. Various cooling technologies are benchmarked. The finned-type cooling technique is chosen over other methods due to simplicity and low pressure drop. Integrated cooling or direct cooling of the module’s baseplate is selected due to considerable thermal resistance reduction because of thermal grease elimination. Potential fabrication techniques are thoroughly explored and compared in terms of mass production and prototyping suitability. Four different fin shapes, including circular (baseline), drop-shaped, symmetric convex lens, and offset strip in the staggered arrangement, are studied herein. The cooling agent is Water and Ethylene Glycol 50% volumetric mixture (WEG 50%). Typical operating conditions in electrified vehicles (EVs) such as flow rate and inlet temperature are assumed for the numerical analysis. A grid convergence study is carried out to ensure numerical solutions are within an acceptable error band. The thermal performance evaluation results showed that, on average, offset strip, drop-shaped, and the convex lens performed 39%, 20%, and 6% better than the baseline design, respectively. Additionally, the design candidates are compared in terms of mass and estimated machining cost. The results of the baseline case are verified against empirical correlations from the literature. The maximum deviation is less than 1% and 1.2% for finned-surface temperature and pressure drop, respectively. The difference is attributed to the end-wall effects. / Thesis / Master of Applied Science (MASc)

We have come a long way in the pursuit of reducing our carbon footprint from our way of living, bycontinuously development of batteries and charging infrastructure for electric vehicles to decrease thedemand for fossil fuels, improving the overall energy efficiency and to increase awareness of the problemto the population. One of the industries, that during the last decades has undergone vast improvements,is the development of the airplane engines due to increased emission regulations, for the aviationindustry, and to reduce the costs of air travel. Despite tighter regulations, global impact from travellingby air is increasing due to the explosive increase in number of travels and travellers. In order to copewith the situation, it is of course necessary to further develop fuel and emission effective airplanes, butalso to study the whole chain of emission sources correlated to the air transport industry. So, whilewaiting for improved airplanes there are well known emission effective technologies that can beimplemented already today – implement electric vehicles as support vehicles at airports.Today, and throughout history, most of the focus of air travel has been on the airplane itself. This thesis,that was carried out at KTH Royal Institute of Technology during late spring and autumn 2018, didinstead study the support vehicles used in airports. In this thesis, a generic economic model wasdeveloped in order to estimate the costs involved when replacing traditionally vehicles to suggestedelectrically propelled alternatives. To test and support the development of an economic model, a casestudy has been carried out at Stockholm Arlanda Airport. This case study included a field study to thementioned airport, and in combination with interviews with former employees from one of the groundhandling companies that are currently active in the airport. Raw data was collected over the equipmentand vehicles currently in use. This data was used to describe the vehicles purpose, requirements and toensure that the alternative electric vehicles proposed would offer at least the same performance as thetraditional vehicles. The developed generic economic model was modulated with five stages thatrepresented a selection of input parameters. The collected data became a result in itself and was used asinput to three concurrent theses.The results from the five stages presents the costs during an investment period of between of one tofifteen years. One of the most significant result could be seen from Stage V. This stage showed that thecombined cost to replace all vehicles currently used, with either all new diesel vehicles or electricalternative vehicles, are lower for electric vehicles than for diesel vehicles. Another significant resultcould be seen from the investigation of Stage IV, Stage IV-B, were the model was modulated to representthe case of replacing a vehicle. The results showed that the Letter and Cargo procedures, that travel thefarthest and has the highest fuel consumption of the investigated vehicles, had negative costs throughthe whole investment period. This means that the expenses will always be lower when these vehicles arereplaced. The model was validated through a sensitivity analysis, performed on the discount rates,depreciation rates and as well as costs for battery replacement during the depreciation period. / Vi har kommit långt i vår strävan att minska vårt koldioxidavtryck genom vårat sätt att leva, genom attkontinuerligt utveckla batterier och laddningsinfrastruktur för elfordon med syftet att minskaefterfrågan på fossila bränslen, förbättra den totala energieffektiviteten och öka befolkningensmedvetenhet om problemet. En av de branscher, som under de senaste decennierna har genomgått storaförbättringar, är utvecklingen av flygplansmotorer och regler för flygplan. Men eftersom antaletflygresenärer fortsätter att öka årligen krävs ytterligare arbete för att förbättra den totala effektivitetenoch minska det negativa globala avtrycket från flygresor. Medan väntan på att morgondagens flygplanska utvecklas så finns det teknik som redan kan appliceras idag – elfordon.I dag, och genom historien, har det mesta av all fokus för flygresor varit på flygplanen själva. Dettaexamensarbete, som genomfördes på KTH, Kungliga Tekniska Högskolan, under den senare delen avvåren och hösten 2018, utredde istället de fordon som omger ett flygplan, under den tid flygplanet stårstilla på en flygplats. Under denna uppsats utvecklades en generisk ekonomiskmodell, med syftet attestimera kostnaderna att ersätta och använda elfordon istället för de nuvarande fordonen. För attutveckla den ekonomiska modellen genomfördes en fallstudie på Stockholm Arlanda Airport.Fallstudien innehöll en fältundersökning till den nämnda flygplatsen, och i kombination med intervjuermed tidigare anställda från ett av de marktjänstföretag som är verksamma på flygplatsen, insamladesrådata om vilken utrustning och fordon som vid tillfället användes. Denna data användes för att beskrivafordonens syfte, vilka krav som ställs på fordonen. Detta var för att säkerställa att det valda elfordonetkunde utföra uppgiften. Den utvecklade generiska ekonomiska modellen modulerades med fem steg,som representerade vilka indataparametrar som bör väljas. De insamlade uppgifterna blev ett resultat isig och användes som indata till tre samtidiga avhandlingar.Den generiska modellen resultat presenterade kostnaderna från de fem stegen under en varierandeinvesteringsperiod på ett till femton år. Ett av de viktigaste resultaten var från Steg V, som visade attden sammanlagda kostnaden för att ersätta alla de fordon som för närvarande används, med antingenalla nya dieselfordon eller elektriska alternativa fordon, är lägre för elfordon än för dieselfordon. Detandra betydande resultatet kommer från undersökningen av Steg IV, Steg IV-B. I Steg IV-B moduleradesmodellen i syfte att representera scenariot då ett fordon ska ersättas, där Letter och Cargo procedurernavar de som färdades längst och även har den högsta bränsleförbrukningen utav de undersökta fordonen,hade en negativ kostnad under hela investeringslängden. Detta betyder att kostnaderna alltid är lägre,om fordonet ersätts. Modellen har validerats med hjälp utav en känslighetsanalys som utfördes pådiskonteringsräntan, avskrivningssatsen och kostnader för ersättningsbatterier.

<p dir="ltr">In this thesis, a MATLAB model was used to simulate a 2-vehicle platoon where the lead truck is a conventional class 8 vehicle while the key parameters of the following truck was tested in various road conditions to minimize Inter vehicular Distance (IVD) and maximize fuel savings while ensuring safety</p>