Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Numerical and Experimental Investigation of an Electric Vehicle Battery Module Thermal Management System(Izmir Institute of Technology, 2022) Gediksiz, Çağlar; Çetkin, ErdalToday, electric vehicles play an essential role in preventing pollution from fossil sources. Therefore, it is vital to develop battery technology in electric vehicles. The biggest problem experienced is the thermal runaways, which is a phenomenon that may cause burning and explosions following the decrease in battery capacities. The thermal runaway problem can be solved by using the thermal management system to keep the temperature range under control. In this study, a 6.7 kWh battery pack was produced. Battery pack operation consists of two parts, mechanical and thermal. In the mechanical part, battery pack assembly and drop tests, one of the mechanical tests, were carried out. At the end of the battery pack assembly, voltage measurements were made, and the accuracy of the assembly was demonstrated. Besides, a numerical and experimental study supported drop tests. As a result of this study, the battery case did not show permanent deformation (2.529x 108 N/m2) as suggested in the numerical experiments (1.263x 108 N/m2). Discharge characteristics and battery module model were discussed in the thermal management part. The information in the literature confirmed the discharge characteristic. The gap between the battery cells reached its most efficient value at 8 mm. In the developed battery module, thermal management was attempted using a heat plate and a cooling pipe. According to the numerical results, the battery module reaches 311.37K at 10C discharge. In the experimental process, the battery pack was charged with 15 amps and discharged with 30 amps. Moreover, the temperature values reached a maximum of 31 degrees. In the experiment on electric vehicles, a maximum discharge level of 255 A was observed. In this experiment, the battery pack reached a maximum of 36 degrees.Master Thesis Computational Fluid Dynamics (cfd) Analysis of Latent Heat Storage in Heat Exchangers by Using Phase Change Materials (pcm)(Izmir Institute of Technology, 2020) Demirkıran, İsmail Gürkan; Çetkin, Erdal; Rocha, Luiz Aberto OliveiraThe development of TES applications and materials takes the attention of many researchers, but the current literature rarely involves studies concerning medium temperature applications. This thesis compares available phase change materials (PCMs) for the medium temperature range. For this aim, Erythritol was defined as PCM in the numerical analyses. The effect of heat transfer fluid (HTF) tube position and shell shape on the melting time and sensible energy requirement for melting a phase change material (PCM) in a latent heat thermal energy storage (LHTES) application were investigated. Tube location and shell shape are essential due to the shape of the melted region, i.e., similar to the boundary layer. Results show that the S-curve of melting becomes steeper if the tubes are distributed such that the intersection of melted regions is delayed. Therefore, melted regions should be packed into a finite space which uncovers the shape of the shell that minimizes melting time and required sensible energy. Results show that, rectangular-shaped shell design where the tubes located near the bottom end decreases melting time and sensible energy from 67 minutes to 32 minutes and from 161.8 kJ/kg to 136.3 kJ/kg for %72.3 liquid fraction relative to the circular-shaped shell, respectively. In the four-tube cases, then the required melting time and sensible energy decrease 80% and 3.8% through the rectangular-shaped shell design for the PCM to melt completely, respectively. Overall, the results show that sensible energy storage and especially melting time can be decreased greatly by just varying the design.