## THERMAL SCIENCE

International Scientific Journal

### MIXED CONVECTION HEAT TRANSFER PAST IN-LINE SQUARE CYLINDERS IN A VERTICAL DUCT

**ABSTRACT**

The mixed convection heat transfer around five in-line isothermal square cylinders periodically arranged within a vertical duct is numerically investigated in this paper. Spacing between two cylinders (S) is fixed at one width of the cylinder dimension (d) and the flow confinement of various degrees are studied for the blockage ratios of B = 0%, 10%, 25% and 50%. The buoyancy aided/opposed convection is examined for the Richardson number (Ri) ranges from -1 to +1 with a fixed Prandtl number Pr = 0.7 and Reynolds number Re = 100. The transient numerical simulation for this two-dimensional, incompressible, laminar flow and heat transfer problem is carried out by a finite volume based commercial CFD package FLUENT TM. The representative streamlines and isotherm patterns are presented to interpret the flow and thermal transport visualization. Additionally, the time and surface average skin friction coefficient (Cf), drag (CD) and lift (CL) coefficients as well as the time and surface average Nusselt number (Nu) for representative cylinders are determined to elucidate the effects of Re and Ri on the flow and heat transfer phenomena.

**KEYWORDS**

PAPER SUBMITTED: 2010-10-04

PAPER REVISED: 2012-02-08

PAPER ACCEPTED: 2012-11-24

**THERMAL SCIENCE** YEAR

**2013**, VOLUME

**17**, ISSUE

**Issue 2**, PAGES [567 - 580]

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