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Abstract (summary): In this thesis, a numerical investigation was carried out on Polymerase Chain Reaction (PCR) machine. PCR is used in a wide variety of industrial applications. One of its main applications is in biomedical field where it is used to multiply DNA molecules. To duplicate DNA samples with a high quality and precision, the temperature uniformity on DNA samples plays a significant role. To study the temperature field, a three-dimensional Computational Fluid Dynamics (CFD) model of PCR device was developed in ANSYS CFX. In this study, initially, both the denaturation and post elongation steps were simulated in the complete PCR device, where temperature uniformities of 0.36â and 0.06â were obtained for these steps, respectively. Subsequently, only the air duct and heat sink sections of the PCR device were considered in the simulations to investigate the effect of both the fin length and the gap between the heat sink and air duct on heat removal performance of the device. It was found that by removing the gap between the heat sink and the air duct and cutting the heat sink in half, the efficiency of the heat sink will increase. Finally, an experimental investigation was carried out to compare the performance of aluminum metal foams with regular aluminum heat sinks in terms of heat removal, temperature uniformity, and the outlet temperature of the heat exchanger. It was observed that due to the high surface area to volume ratio of metal foams they can remove heat at a faster rate which leads to a shorter cycling time and a better temperature uniformity in PCR devices.