Numerical Simulation on Effect of Air Attack Angle on Wake and Vortex Formation for Tandem Elliptical Cylinders
6 Pages Posted: 12 Feb 2018
Date Written: December 21, 2017
The cross flow heat exchanger is used most commonly used in process heat transfer applications. The most commonly used tube geometry is a circular tube. However elliptical tube section is prominently used in recent times due to streamline tube profile. The present work is on elliptic tubes in cross flow with different attack angle from 0° to 90°. The effect of oncoming fluid attack angle on boundary layer, wake and vortex formation at the tube downstream is studied at Reynolds number of 7000. The pumping power increases as the attack angle is increased from 0° to 90°, which increases the turbulence within tubes. The numerical simulation is performed in ANSYS 14.5 with RNG k-ε turbulence model. The vortex formation also intensifies with the attack angle of the cross fluid. This increases the turbulence and pressure drop with the tubes which is not desirable. The pumping power is relatively low at the lower attack angle of the air but increases drastically above at 60° and above angles. The attack angle up to 30° is recommended by considering the heat transfer enhancement and pumping power both for the present study.
Keywords: elliptic tubes, cross flow
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