ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
A THEORETICAL STUDY ON HEAT TRANSFER FOR A DEVELOPING LAMINAR PULSED FLOW OF AIR IN TUBE
Abstract
Some results in heat transfer for a developing
laminar pulsed air flow in duct are presented.
They have been investigated by means of a
finite difference numerical model. This flow is
described in terms of an unsteady pulsed flow superimposed to a steady incompressible flow with the
main following assumptions: a sinusoidal modulation
for the pulsation and a uniform wall temperature.
The model confirms the analytical and experimental
results related to the velocity and temperature
laws in the steady regime. A realistic understanding
of the RICHARDSON' annular effect and especially
its damping in the entry region is proposed.
Unsteady heat transfer characteristics can be explained mainly by the existence of an annular effect in temperature. By pulsating the flow, a significant transfer increase would occur in the developing length and the model suggests the existence of a low frequency promoting an optimum in this zone.