Characteristics of Refrigerant Film Thickness, Pressure Drop, and Heat Transfer in Annular Flow

Hurlburt, E.T.; Newell, T.A.

Permalink

https://hdl.handle.net/2142/11545 Copy

Description

Title

Characteristics of Refrigerant Film Thickness, Pressure Drop, and Heat Transfer in Annular Flow

Author(s)

• Hurlburt, E.T.
• Newell, T.A.

Issue Date

1997-02

Keyword(s)

• two-phase modeling
• refrigerant-oil mixtures

Abstract

Common refrigeration and air conditioning cycles are dependent on two-phase flow for efficient heat transfer with minimal pressure drop. Design of heat exchangers for these systems is aided by an understanding of the refrigerant pressure drop and local heat transfer coefficient. An estimate of the liquid fraction is also important for predicting the charge required in a system. The present work develops a semi-analytical model for predicting liquid fraction, pressure drop, and heat transfer for pure refrigerants in the annular flow regime. The model uses the approach of coupling a uniformly thick, turbulent liquid film layer with a turbulent vapor core. Model predictions are compared to experimental evaporation and condensation data for Rll, R12, R134a, and R22. These refrigerants represent the low, medium, and high pressure ranges found in common refrigeration systems. The uniform film model, when compared to experimental data, provides a reference for understanding some of the mechanisms that are important to refrigerant two-phase flow.

Publisher

Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.

Series/Report Name or Number

Air Conditioning and Refrigeration Center TR-110

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/11545

Sponsor(s)/Grant Number(s)

Air Conditioning and Refrigeration Project 71

Owning Collections