A Three Dimensional Numerical Study on Heat Transfer of a Backward-facing Step Flow in a Rectangular Duct - Effects of the Inlet Velocity Profile and Channel Aspect Ratio

摘要

Three dimensional flow and thermal fields have been solved numerically for the stepped duct flow for different inlet flow conditions, uniform flow and fully developed flow. Larger maximum heat transfer near the side wall and unique lower heat transfer at the center are attained in the developed flow case while more uniform heat transfer is obtained in the uniform flow case. Particle trajectory analysis revealed that this larger maximum heat transfer is produced by intensive downward fluid motion and the lower heat transfer is caused by the large scale spiral fluid motion flowing downstream from the centerline of the duct.