Research Information System
Thesis Type: Doctorate
Institution Of The Thesis: Gazi University, Fen Bilimleri Enstitüsü, Turkey
Approval Date: 2022
Thesis Language: Turkish
Student: MURAT PARLAK
Principal Supervisor (For Co-Supervisor Theses): Abuzer Özsunar
Co-Supervisor: Ali Koşal
Open Archive Collection: AVESIS Open Access Collection
Abstract:
Due to the confined space allocated for cooling, the thermal problem of electronics has continuously increased for the last two decades. Every year, the equipment size gets smaller and its power dissipation goes up to obtain a compact and high-performance product. It is well known that the performance and life directly depend on the temperature. In this study, a straight rectangular microchannel has been studied due to its high performance and relatively easier producibility compared to other fin designs. In a rectangular channel, the channel aspect ratio is a very important parameter affecting both thermal and hydrodynamic performance. Because of this, a high aspect ratio channel has been deliberately studied to have high cooling performance and lower pressure drop. Aluminum 6063-T05 has been used as the solid material and ethylene glycol distilled water mixture (EGW) has been selected as the liquid to have sufficient cooling performance. EGW is mostly the preferred liquid in industrial and military cooling applications due to its low freezing point. Totally 216 3D conjugated CFD analyses are carried out to find the optimum solution which enables Rth< 0.2 °C/W and the lowest pump power. After analyzing all results, it is seen that the channel with the parameters of total fin thickness = 120 µm, channel space = 120 µm, and channel height = 2 mm is the best that fits all requirements at the pressure drop of P= 20 kPa through the channel. The optimized channel has been produced with EDM technology and a highly accurate test set-up has been prepared to minimize any error at the measurement stage. The microchannel heat sink has been tested with different flow rates and Nu numbers, Rth, and h are calculated both numerically and experimentally. The results are compared with the literature and it is evaluated that the experimental Nu number in the thermal developing region is higher than both numerical and suggested correlations in the literature. In addition, pressure drop through the channel has been measured and it is evaluated that the experimental results are higher than the numerical values
Key Words : Minimum Power Consumption, Constructal Law, High Aspect Ratio,
Rectangular Microchannel, Thermally Developing Region