SURFACE ROUGHNESS EFFECTS ON NUCLEATE BOILING HEAT TRANSFER RATES
Abstract
Heat transfer rates were measured for pool boiling, in the nucleate regime at one atmosphere pressure, for distilled water on a horizontal, flat, stainless steel (Type 304) plate. Results are presented as delta tm, temperature difference between the heating surface and the distilled water, as a function of heat rate, q/A for a given surface roughness. Heat rates covered a range from a maximum of 29,000 Btu/hr sq ft to a minimum of 2550 Btu/hr sq ft while delta tm varied from 39 to 0.5 F. Ten surface roughnesses were tested in the range of 3 to 100 micro inches rms. One specimen with .005 in. grooves and another with . 008 in. grooves were also tested. The results indicate that as surface roughness increased the delta tm necessary to maintain a given heat rate decreased until a roughness of about 30 micro inch rms. Thereafter, little effect of increased roughness was noted. As an example for a heat rate, q/A, of 20,000 Btu/hr sq ft, delta tm was 36.5 F for a roughness of 3.1 micro inch rms. and decreased to 17.5 F at 23 micro inch rms.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1962
- Accession Number
- AD0481219
Entities
People
- James C. Gibson Jr.
Organizations
- Naval Postgraduate School