Numerical Investigation of Turbulence Models for Separation Fluid Flow in an Annular Passage in Regenerative Pipe

Document Type: Original Article

Authors

Industrial & Mining Research Center, Cycle Science And Industry Company, Tehran, Iran

Abstract

Separation and reattachment of airflow through a sudden expansion in an annular passage with
uniform heat after step are considered in this paper. The annular passage with step is applied in the
design of many heat related applications where heat transfer is concerned. In this work, numerical
simulation for many turbulence models is performed using computer fluid dynamics package
(commercial software) to study the effect of step flow in an annular passage. The numerical results are
compared with the preliminary experimental data. The annular passage, the flowing fluid was
considered when heated uniformly from the beginning of the expansion. Constant heat flux approach
was also considered for the heat transfer investigation. Annular pipe flow system having Reynolds
number of 17,050 and uniform heat flux equal to 2098 W/m
2 and a step ratio of D/d=1.8 was
considered where
d and D were representing the diameter of the pipe before and after expansion.
Numerical simulation review shows that the reattachment point extends further with the increase of
velocity for different occasions. Finally, experimental results for surface temperature (
Ts) and local
Heat transfer
(h) are compared with CFD results after expansion for many turbulence models

Keywords