maximal value at about Re ¼ 2500 and decreases afterwards.
The reason is that flow nonuniformity (S) increases
with the Re in laminar flow region. With the
increase of Re, the flow in the central zone of the header
starts to change from laminar into turbulence flow at
about Re ¼ 2500. The change of flow pattern leads to
new distribution of the local flow resistance between the
central zones and the other parts of the header, which
further leads to the flow redistribution in header. Fig. 5
also shows that the working pressure only has a small
influence on flow distribution, so the effect of working
pressure can be neglected in the optimum design of the
header configuration and operation. Oppositely, the
computational results show that the Reynolds number is
an important factor affecting the flow distribution in
plate-fin heat exchangers. Therefore, consideration
should be taken into account for Reynolds number in
the design and operation of heat exchangers.
A comparison was conducted between the flow velocity
predictions and the experiments in Fig. 6. It is
found that the CFD prediction is in good agreement