Oda sıcaklığı civarındaki uygulamalar için manyetik soğutma sisteminin sayısal incelenmesi

In this thesis, the magnetocaloric effect and engineering applications of magnetocaloric regenerator are examined numerically. Two different types of regenerators, namely, cylindrical and parallel plate regenerators, are considered. Each of them made of Gadolinium element, which is commonly used in magnetic cooling technology as a magnetocaloric material. Parallel plate regenerator consists of Gadolinium plates arranged parallel to each other. The cylindrical regenerator contains cylindrically shaped Gadolinium. Heat transfer fluid is driven with pistons in parallel plate regenerator, but cylindrical regenerator is using pumps for driving heat transfer fluid. Magnetocaloric effect (MCE) was obtained by Weiss's mean field theory, and also dimensionless MCE characteristics are determined with an alternative method, namely mean-field approximation. SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) algorithm was used for the solution of continuity and conservation equations. Basically, the cycle duration, piston velocity, pressure difference value, utilization factor, and design ratio are selected parameters, and the most suitable operating conditions within these parameters are determined. MCE characteristics are obtained coherently with literature. The maximum temperature span is observed as 9.9 K for piston velocity 0.15 cm/s and 8.28 K for 1.2 s cycle duration for parallel plate regenerator and cylindrical regenerator, respectively. Furthermore, structural examination at cylindrical regenerator shows that smaller Gadolinium diameter increases maximum temperature span and temperature span is calculated as 8.85 K for 1.2 s cycle duration and 40 mm Gadolinium radius. In conclusion, the most important result is increasing cycle durations, and heat transfer fluid velocity has a negative effect on regenerator performance.