| An experimental facility with relevance for many industrial applications incorporating continuous processes was built, and flow visualization and particle image velocimetry implemented in order to investigate the effect of complex confinement and moving boundaries on the flow characteristics. Extensive experimental and computational investigations of a slot jet, a 3 x 11 jet array and of a row of 13 square jets are discussed. The experiments and numerical simulations investigated the effects of the impingement surface velocity, jet Reynolds number, impingement distance and separation distance between rollers. The Reynolds number was varied from 500 to 2000, and the non-dimensional impingement surface velocity, Vs/Vj, from 0 to 1. Non-dimensional impingement distances of 3 and 5 were investigated and computations were performed for non-dimensional separation distance of 6, 8, 10 and 16.8. The results obtained for the slot jet document a notable jet deflection in the direction opposite to the impingement surface direction of movement. The jet deflection increases with the impingement surface velocity and with the impingement distance and decreases with increasing Reynolds number. Simulations showed that the boundary layer thickness reaches a local maximum at the impingement point, which can be related to the local maximum shear stress. For the jet array and the row of jets, the jet-to-jet interaction and the flow complexity increased with increasing impingement distance. Complex secondary flows with a dominant direction of motion in the opposite direction of the impingement surface movement were documented. A comparison of the heat transport performance showed that the row of jets has a higher heat transport effectiveness than the slot jets for the same flow rate. The moving boundaries intensify mixing and the flow unsteadiness and augment the heat transfer at the impingement surface for all investigated nozzles. |
