Nucleate Pool Boiling Characteristics of Gewa-T Finned Surfaces in Freon-113.
Abstract
Pool boiling heat-transfer measurements were made using seven Gewa-T copper tubes in R-113. The first tube (18-mm OD x 0.75 fins/mm x 0.25 mm gap) was tested under three conditions: (a) plain, (b) with four shrouds and (c) with up to 5 wires (0.13 mm diameter) wrapped in the inter-fin trough area. Verifying prior data, the shroud with longitudinal openings of 60 deg at the top and 8.5 deg at at the bottom gave the best performance among the four shrouds tested. This shroud increased the boiling heat-transfer coefficient by 253 percent (over the smooth tube case) at a heat flux of 10,000 W/sq m while it showed only a 18 percent increase at 100,000 W/sq m. When wire wraps were provided, in all cases, the heat-transfer coefficient was improved at all heat fluxes. The use of three wires gave the best performance with 341-percent increase in heat-transfer coefficient at 10,000 W/sq m and a 130 percent increase at 100,000 W/sq m. The next three Fewa-T tubes had dimensions of 25 mm OD x 0.75 fins/mm with fin-tip gaps of 0.15, 0.25, and 0.35 mm, respectively. The last three Gewa-T tubes had the same dimensions except that the fin density was 1.02 fins/mm. For each of these fin densities, the 0.25 mm fin-tip gap produced the best boiling performance at all heat fluxes. Originator supplied keywords include: Nucleate pool boiling; Gewa-T finned surfaces.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1984
- Accession Number
- ADA152286
Entities
People
- R. J. Pulido
Organizations
- Naval Postgraduate School