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Velocity distributions in (r,θ) directions for laminar flow of a film around horizontal circular tube

Abyaneh, M. H. J ; Sharif University of Technology | 2006

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  1. Type of Document: Article
  2. Publisher: 2006
  3. Abstract:
  4. Velocity distributions in (r,θ) directions are evaluated by solving simultaneous simplified Navier-Stokes equations (NSE) and continuity equation (CE) in polar coordinate. The analysis is based on steady state laminar flow of thin falling liquid film on a horizontal circular tube, for cases in which traction on the film surface is considered negligible. It is a common geometry for part of engineering problems such as evaporator, condenser, absorber, generator of absorption chillers and other similar units in mechanical and chemical engineering. Knowledge of the velocity profiles is usually needed for: 1- solving governing energy and species equations 2- estimating the average and film surface velocity, and 3- evaluating film thickness distribution and its gradient. Two models of velocity distributions are considered, namely actual model and simplified model. Models are compared not only with each other but also with semi actual model in (x,y) coordinate given in the literatures. The average and film surface velocity profiles and film thickness distribution for these models have been shown in various conditions. The results clearly show that the larger flow rates and / or smaller tube diameter increases the calculation error. Copyright © 2006 by ASME
  5. Keywords:
  6. Mathematical models ; Navier Stokes equations ; Thickness measurement ; Thin films ; Absorption chillers ; Circular tubes ; Continuity equation (CE) ; Falling liquid films ; Velocity distributions ; Laminar flow
  7. Source: 2006 2nd ASME Joint U.S.-European Fluids Engineering Summer Meeting, FEDSM 2006, Miami, FL, 17 July 2006 through 20 July 2006 ; Volume 2006 , 2006 ; 0791837831 (ISBN); 9780791837832 (ISBN)
  8. URL: https://asmedigitalcollection.asme.org/FEDSM/proceedings-abstract/FEDSM2006/47500/11/319046