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 : NOV 1972

Pagination or Media Count : 148

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 Condition, Heating, Lighting & Ventilating
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE