Study on the turning of inner pipe flow into outer annulus flow in a concentric double pipe (flow visualization and head loss)

摘要

Concentric double pipes are used in engineering design such as a bayonet heat exchanger and a biochemical reaction tube. It is important to know the relation between the head losses and flow patterns of the turning flow into the annulus from the inner pipe, for various values of the ratios of cross-sectional area A, (A, is defined as the annulus area divided by the inner pipe area) and nondimensional clearance length L/d, (defined as the distance L between the bottom of outer pipe and the outlet of inner pipe, divided by the inner pipe diameter di).