擬塑性流体の二重管内乱流速度分布

Abstract

The velocity distributions in fully developed turbulent flow of pseudoplastic fluids in annuli were investigated by dimensional analysis method employed by Millikan.The validity of the theory in this study was examined by using the experimental data. Mean velocity distribution and the location of the maximum velocity were measured in the turbulent flow of Newtonian fluid and pseudoplastic fluids in annuli. Diameter ratio k of annuli and flow behavior index n were varied between k=0.118-0.642 and n=0.870, 0.823, 0.760, respectively and Reynolds numbers were ranged from 4580 to 102000.It has been found that the point of maximum velocity in turbulent flow in an annulus do not depend on flow behaviorn, but diameter ratio k.In addition, the analysis permitted the prediction of mean velocity of turbulent flow of pseudoplastics fluids in an annulus.V=u*0[A0nkln{R0nρu*02-n/K(1-λ)n}+B0nk]-n/2(1+k) A0nku*0 (3+3k-2λ)k=ratio of radius, λ= dimensionless radial distance of maximum velocity, n=flow behavior index, K= fluid consistencyi ndex, ρ= density, R0= radius of outer tube of annuli.u*0=frictionvelocityreferredtoouterwallofannulus, Aonk, Bonk=fhnction of n and k in the outer regions.To confirm the results due to theoretical analysis, the experimeptal tests were carried out by using the bentonite slurrles under the turbulent flow, and almost experimental data showed the validity about the above mentioned analysis within the mean deviation of 2.5%.