The effecting of a sudden step change on heat transfer coefficient

الملخص EN

Numerical techniques and theoretical results for incompressible laminar separated flows were presented.

For the case of the internal flow over backward facing step.

The heat transfer processes and the flow behavior were affected with type of the fluid, expansion ratio, and Reynolds number.

It was found that, an increasing in Reynolds number leads to increase the vorticity strength and the size of the recirculation zone in linear relation.

This increasing in each of size of the recirculation zone and vorticity strength depends on the expansion ratio.

Also, it was found that the average Stanton number in the recirculation zone decreases with increasing of Reynolds number at lower expansion ratios.

For high expansion ratios, the average of Stanton number in the recirculation zone, increases with increasing Reynolds number for range of Reynolds number of (Re < 175), and decreasing with increasing Reynolds number for range of Reynolds number of (Re > 175).

The results were represented for the reattachment length (Rl) and for the average Stanton number in recirculation zone ('si).

Also, velocity distribution, vorticity distributions, temperature distributions, were presented for range of Reynolds number greater than 25 and less than 1000 for different conditions.