NUMERICAL INVESTIGATION OF FLUID FLOW IN CAPILLARY TUBES

Abstract

This study was interested with fluid flow through narrow tubes. Finite volume method has been used as a numerical technique by the aid of computer to achieve the study. Cylindrical narrow tubes, represented as case A and case B have been used. Case A was a tube of radius (2 cm) and length (20 cm) while case B which has been used to investigate the effect of narrow tube on fluid flow was a tube of radius (2 mm) and length (20 mm). The initial conditions and boundary conditions for both cases were similar. Due to its widespread applications, air has been used as fluid material for the both cases. No slip condition at the wall has been used and viscous fluid flow was considered for both cases. Different parameters have been investigated for the two cases and have been compared to each other such as velocity magnitude, dynamic pressure, static pressure and wall shear stress. Case A has Reynold's number (Re) higher than case B. The velocity profiles of fully developed flow were compared with the parabolic velocity profile. Clear difference between the two cases A and B has been shown because of the narrowness of case B. The maximum velocity was at the tube centerline and zero at the tubes wall because of no slip condition was applied. Due to the differences in the diameters of the two cases, the results showed apparent differences between the two cases for velocity magnitude, dynamic pressure, static pressure and wall shear stress as well. The results of this study could be important for applications which include air flow in narrow tubes.