Accession Number : AD0762368


Title :   Effects of Surface Conditions on Boiling Characteristics,


Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE ENGINEERING PROJECTS LAB


Personal Author(s) : Lorenz,J. J. ; Mikic,B. B. ; Rohsenow,W. M.


Report Date : DEC 1972


Pagination or Media Count : 35


Abstract : A unified model relating surface variables to the nucleate pool boiling characteristics was developed. A simple vapor trapping mechanism was postulated and a geometrical model constructed for idealized conical cavities relating the effective radius for nucleation to cavity radius, cone angle and contact angle. This model for individual cavities was extended to the entire surface providing an expression for the cumulative site density in terms of geometrical parameters. A gas diffusion technique was developed to measure the effective radius for natural cavities and was used successfully to verify the nucleation criteria Delta T = 2(sigma)(T sub s)(V sub fg)/h(fg)rho. A transient heat conduction model was esxperimentally verified for water and organics at atmospheric pressure and was incorporated into a unified expression showing explicitly the role of surface geometry and contact angle. (Author)


Descriptors :   (*NUCLEATE BOILING, *SURFACE PROPERTIES), NUCLEATION, THEORY, NUMERICAL ANALYSIS, HEAT TRANSFER, DIFFUSION


Subject Categories : PHYSICAL CHEMISTRY
      THERMODYNAMICS


Distribution Statement : APPROVED FOR PUBLIC RELEASE