N. Dombrowski et al., THE INFLUENCE OF REYNOLDS-NUMBER ON THE ENTRY LENGTH AND PRESSURE-DROP FOR LAMINAR PIPE-FLOW, Canadian journal of chemical engineering, 71(3), 1993, pp. 472-476
A numerical analysis of the laminar flow of a Newtonian fluid in the i
nlet section of a circular pipe has been carried out for a Reynolds nu
mber range of 0 to 500, employing a finite element based CFD code. A n
ew flow phenomenon has been identified at low Reynolds numbers (< 50),
viz, the existence of a peak in the axial pressure profile at a small
distance from the entrance. Existing correlations for the entry lengt
h are shown to be insufficient and a new correlation for the entry len
gth is proposed.