Papers by Author: Antar M.M. Abdala

Abstract: In the present work, computational simulations was made using ANSYS CFX to predict the improvements of internal heat transfer in rectangular ribbed channel using different coolants. Several coolants such as air, steam, air/mist and steam/mist were investigated. The shear stress transport (SST) turbulence model is selected by comparing the predictions of different turbulence models with experimental results. The results indicate that the heat transfer coefficients enhance in ribbed channel at injection small amount of mist. The heat transfer coefficients of air/mist, steam and steam/mist increase by 1.13, 1.57 and 2.07 times than that of air, respectively. Furthermore, comparing with droplets size, the proper size is from 6 to 10 µm. which had the best enhancement performance in ribbed duct.

Abstract: In this study, computational simulations were made using ANSYS CFX to predict the improvements in film cooling performance with multi trench. Multi-trench configuration consists of two trenches together, one wider trench and the other is narrow trench that extruded from the wider one. Several blowing ratios in the range (0.5, 1, 2 and 3) were investigated. By using the multi trench configuration, the coolant jet impacted the trench wall two times allowing increasing the spreading of coolant laterally in the trench, reducing jet velocity and jet completely covered on the surface. The results indicate that this configuration increased adiabatic effectiveness as blowing ratio increased. The multi trench configuration increased adiabatic effectiveness up to 100% near the hole, 43% at X/D = 40 and 31% at downstream X/D = 137 for blowing ratio of 3 and no observed film blow-off at this blowing ratio. The adiabatic film effectiveness of multi trench configuration outperformed the narrow trench at different blowing ratios