Forced flow laminar filmwise condensation of a pure saturated vapor in a vertical tube

Flavio Dobran, Richard Thorsen

Research output: Contribution to journalArticle

Abstract

An analytical study of steady laminar, filmwise condensation of a saturated vapor in forced flow in a vertical tube has been conducted for the case when the vapor velocity profile at the tube inlet is fully developed and the tube wall temperature is maintained constant. Equations and boundary conditions governing the condensation process have been examined in detail in order to determine relevant parameters of the problem. For a wide range of conditions of practical interest it is found that the condensation process is governed by five parameters. These are the ratio of vapor Froude to Reynolds number, Buoyancy number, vapor to liquid viscosity ratio, liquid Prandtl number and Subcooling number. A numerical solution of the resulting set of equations shows considerable differences in hydrodynamics and heat transfer with variations in these parameters. Comparison of the results with Nusselt's analytic solution of constant interphase shear is also made and it is found that at high pressures, high Prandtl numbers and high ratios of Froude to Reynolds numbers, his analytic solution underpredicts the condensation length and film thickness and overpredicts the interphase mass and heat transfer. Significant disparities at low Prandtl numbers are found between analytic and numerical solutions for heat-transfer results as well as the hydrodynamic results. These disparities are a consequence of neglecting inertia terms in the liquid and vapor equations of motion in the analytic model and their inclusion in the model presented in this work.

Original languageEnglish (US)
Pages (from-to)161-177
Number of pages17
JournalInternational Journal of Heat and Mass Transfer
Volume23
Issue number2
DOIs
StatePublished - 1980

Fingerprint

laminar flow
Laminar flow
Condensation
condensation
Vapors
vapors
tubes
Prandtl number
heat transfer
Heat transfer
Reynolds number
Hydrodynamics
liquids
hydrodynamics
Viscosity of liquids
wall temperature
Liquids
Buoyancy
buoyancy
inertia

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Energy(all)
  • Mechanical Engineering

Cite this

Forced flow laminar filmwise condensation of a pure saturated vapor in a vertical tube. / Dobran, Flavio; Thorsen, Richard.

In: International Journal of Heat and Mass Transfer, Vol. 23, No. 2, 1980, p. 161-177.

Research output: Contribution to journalArticle

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