| Summary: In this master thesis, the effects of the channel lengths on a circular jet flow, caused by a sudden contraction, were investigated. In a circular air jet formed as a result of a sudden contraction at the outlet of a large square-section duct, velocity measurements in the jet flow area, both in the vertical direction and along the jet axis, was performed using a pitot tube. By adding pipes with different channel lengths to the outlet plate, the effect of these channels on the jet flow is investigated. The experiments were carried out for air jets that suddenly turned into a circular section from a square-section duct with a side length of 25,4 cm. The diameter of the circular jet was determined as 44 mm, 68 mm and 102 mm. For jet streams of these diameters, L/D ratios for channel length are 1, 2, 7 and x/D ratios for distance from jet outlet are 0, 1, 2, 5, 10 and 20. In addition to the experimental measurements, the jet flow was also analyzed numerically by using ANSYS FLUENT software. From the results, it was determined that the channel length significantly affects the velocity profile at the jet exit and this effect decreases as you move away from the jet exit.
Keywords: Free Air Jets, Circular Jet Flow, Sudden Contraction, CFD |
