Numerical Comparison of Temperature Distribution in an Annular Diffuser Fitted with Helical Screw-Tape Hub and Pimpled Hub

摘要

Numerical simulations of temperature distribution in an annular diffuser fitted with helical screw-tape hub and pimpled hub are carried out in this work. Three twist ratios (Y/H) 4, 6 and 8 for the helical screw-tape hub and three twist ratios (Y/H) 4.5, 5.7 and 8 for the pimpled hub are numerically analyzed and compared. The geometry of the annular diffuser and the inlet condition for both hub configurations are kept constant with inlet Reynolds Number 2.5 x 104. The analysis of the flow features with different twist ratios for the helical screw-tape hub and pimpled hub will help the temperature to redistribute in a helical direction (axial and radial directions);; however the helical screw-tape hub gives more effective results. More importantly, the results showed that enhancement of the temperature distribution can be well achieved by decreasing the twist ratio (Y/H).