Abstract
A flow visualization with a smoke sheet method is applied to obtain the relationship between flow patterns and heat transfer for a combined natural and forced convection of developing laminar flow in rectangular duct. Characteristics of flow patterns and heat transfer results are explained in terms of Reynolds number and Rayleigh number.
The duct is placed long side horizontal as well as short side horizontal, and heated from two shorter side walls, and the opposite side of two walls are kept with heat insulator. The aspect ratios of the channel height to the width examined are 1/10 and 10, the range of Reynolds number and Rayleigh number are of 140.45 to 148.49 and 1.03X107 to 3.16X107, respectively.
The flow pattern is found, to be simillar to that of the case with one side-wall heating reported in reference (1) and (2) with some minor modification. The heat transfer results are related with the flow pattern observed. The flow rate of heat when the channel is heated from two side walls is shown to be much higher than the one side-wall heating.
