Reduced Effective Model for Condensation in Slender Tubes with Rotational Symmetry, Obtained by Generalized Dimensional Analysis

TL;DR

This paper develops a reduced model for condensation in slender, rotationally symmetric tubes using generalized dimensional analysis, capturing the physics with greater flexibility and aligning well with existing models.

Contribution

It introduces a novel reduced model derived from generalized dimensional analysis for condensation in cylindrical tubes, enhancing geometric flexibility and physical accuracy.

Findings

Model agrees well with existing literature

Provides a single ODE for film thickness

Increases geometrical flexibility of condensation modeling

Abstract

Experimental results for condensation in compact heat exchangers show that the heat transfer due to condensation is significantly better compared to classical heat exchangers, especially when using R134a instead of water as the refrigerant. This suggests that surface tension plays a role. Using generalized dimensional analysis we derive reduced model equations and jump conditions for condensation in a vertical tube with cylindrical cross section. Based on this model we derive a single ordinary differential equation for the thickness of the condensate film as function of the tube axis. Our model agrees well with commonly used models from existing literature. It is based on the physical dimensions of the problem and has greater geometrical flexibility.