Accession Number:

AD0760037

Title:

The Mechanism and the Magnitude of Flow Boiling Augmentation in Tubes with Discrete Surface Roughness Elements (III).

Descriptive Note:

Final rept.,

Corporate Author:

RAYTHEON CO BEDFORD MASS MISSILE SYSTEMS DIV

Personal Author(s):

• Murphy,Richard W.
• Truesdale,Keith L.

Report Date:

1972-11-01

Pagination or Media Count:

148.0

Abstract:

Related to other research on the effectiveness of flow boiling heat transfer augmentation using various types of turbulators this investigation comprises a definitive study of the effect of large discrete roughness elements on heat transfer over the entire range of forced convection operation -- from single-phase to critical heat flux. It was found that such elements provide significant augmentation 5-6 times smooth tube levels at equal Reynolds number in the single-phase and partial boiling modes. However, the augmentation rapidly degrades as the developed boiling mode is entered. Critical heat flux was, in fact, lowered by 15 - 30 percent with the use of the large roughness elements. Author Modified Abstract

Descriptors:

• (*PIPES
• HEAT TRANSFER)
• (*HEATING ELEMENTS
• COOLING)
• BOILING
• HEAT FLUX
• TEMPERATURE SENSITIVE ELEMENTS
• TURBULENCE
• THERMODYNAMICS
• EXPERIMENTAL DATA

Subject Categories:

• Air Conditioning, Heating, Lighting and Ventilating
• Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE