External Heating of a Circular Annulus Cavity filled with Nano Fluid.

Nowadays, progress in direct absorption solar collectors requires further investigations to realize heat transfer occurring a horizontal annulus cavity exposed external from different angles. An filled with nano-fluid is numerically simulated by using Ansys-Fluent for Rayleigh number equals 105. The wall of two-dimensional model the equally divided into six parts simulate heating isothermal walls placed internal has constant low temperature simulating pipe conveys cold fluid and acting as sink. Hot set angles several cases according hot element position. “Upper”, “lower”, “upper-right”, “lower-right”, “upper & upper-right”, “lower lower-right”, “lower-right “upper-half”, “lower-half” are investigated assess effectiveness all possible directions heating. It found that “lower” “lower-right” about time “upper” case. In addition, improves slightly case compared Heating two or three upper side appears less than lower side. Enlarging area not always reflects multiplication amount, natural convection on decreases significantly due restricted weakened stream motion near poor cases. conclusion, choosing correct direction demonstrates effective earned enlarging area.