Friction coefficients for compressible, large radial Reynolds number, vapor flow in heat pipes
Abstract
Expressions for friction coefficients are presented that can be used to design heat pipes for compressibleflow situations (Mach numbers as high as 1) with very large massinjection/extraction rates (radial Reynolds numbers ranging from + or  100 to + or  20,000). In order to establish these relationships, the flow in a simulated heat pipe, consisting of a porous pipe with air injection and extraction, was numerically modeled. The compressible nonsteady axisymmetric, NavierStokes equations were solved numerically using MacCormack's explicit finitedifference method. No boundarylayer assumptions were made. Also, pressure variations axially and velocity variations axially and radially along the simulated heat pipe were experimentally measured. The experimental data show that numerical solutions gave valid results. Friction coefficient expressions developed using the numerical data were shown to give excellent results when used in a onedimensional model to predict compressible flow dynamics resulting from mass injection/extraction.
 Publication:

26th AIAA Aerospace Sciences Meeting
 Pub Date:
 January 1988
 Bibcode:
 1988aiaa.meetQV...B
 Keywords:

 Coefficient Of Friction;
 Compressible Flow;
 Digital Simulation;
 Gas Flow;
 Heat Pipes;
 Reynolds Number;
 Axisymmetric Flow;
 Laminar Flow;
 NavierStokes Equation;
 One Dimensional Flow;
 Shear Stress;
 Turbulent Flow;
 Fluid Mechanics and Heat Transfer