Solidification blockage of laminar flow in 90.DEG. bend. With reference to dimensionless representation of curved pipe flow.

Abstract

Experiments on solidification blockage of 90° bend laminar flow were made with two R/a ratio double cylinders. The inner pipe of the cylinder was supplied a developed laminar water flow, and through the outer pipe flowed a low temparature coolant supplied from a reservoir. With the ordinary dimensionless axial coordinate for the straight pipe, two critical curves for blokage were obtained according to the R/a ratios. Available calculated and experimental results were used to see a proper dimensionless axial coordinate which could compactly represent curved pipe flow heat transfer, and ζ* = (z/R)/Prm(De·aR)n was selected with m=1 and n=1/2. The two critical curves fall into a single critical curve with the thus derived ζ*0 = (z0/R)/Pr(De·aR)1/2 [u0 = (π/2)·R for 90° bend].