Numerical computation of transient coaxial entry tube flows
Abstract
A numerical program was developed to compute transient laminar flows in two dimensions including multicomponent mixing and chemical reaction. The program can compute both incompressible flows and compressible flows at all speeds, and it is applied to describe transient and steady state solutions for low subsonic, coaxial entry, tue flows. Single component, nonreacting flows comprise most of the solutions, but one steady state solution is presented for trace concentration constituents engaging in a second order reaction. Numerical stability was obtained by adding at each calculation point a correction for numerical diffusion errors caused by truncation of the Taylor series used to finite difference the conservation equations. Transient computations were made for fluids initially at rest, then subjected to step velocity inputs that were uniform across each region of the entry plane and were held constant throughout the computation period. For center tube to annulus velocity ratios of 0.5 and 2.0, the bulk fluid in the tube initially moved in plug flow, but strong radial flows developed near the injection plane which moved the fluid into the high shear region between the jets and away from the tube wall.
 Publication:

Computers and Fluids
 Pub Date:
 December 1976
 Bibcode:
 1976CF......4..123W
 Keywords:

 Coaxial Flow;
 Laminar Flow;
 Pipe Flow;
 Subsonic Flow;
 Transient Response;
 Two Dimensional Flow;
 Chemical Reactions;
 Compressible Flow;
 Finite Difference Theory;
 Incompressible Flow;
 Numerical Stability;
 Radial Flow;
 Steady Flow;
 Truncation Errors;
 Fluid Mechanics and Heat Transfer