- Author
- Kedzierski, M. A. | Han, D. H.
- Title
- Influence of Concentration and Additives on R123/Paraffinic Material Oil Boiling Heat Transfer Performance.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD Korea Univ., Seoul
- Report
- NISTIR 7336, September 2006, 46 p.
- Keywords
- refrigerants | additives | boiling | heat transfer | mixtures | paraffinic mineral oil | enhanced heat transfer | lubricants
- Identifiers
- refrigerant/lubricant mixtures; additive potential; liquid density measurements; capillary rise measurement; lubricant viscosity measurements
- Abstract
- This report investigates the effect that oil concentration had on the boiling performance of an R123/paraffinic mineral oil mixture on a roughened, horizontal flat surface. For all compositions (0.5 %, 1%, and 2%), the lubricant caused a heat transfer degradation relative to the heat transfer of pure R123 of between 2% and 70% for the range of measured heat fluxes. The heat transfer degradation was shown to increase with lubricant mass fraction. The minimum heat transfer degradation for each mixture ranged between 2% and 12% and occurred at approximately 20 kW/m2. For a given composition, the heat transfer degradation increased as the heat flux increased from roughly 20 kW/m2 to 90 kW/m2. In addition, the effect of two trial additives on the pool boiling heat transfer of an R123/paraffinic mineral oil mixture was examined in order to test the validity of a theory for choosing oil additives to enhance boiling performance. The verification tests were inconclusive. More research with lubricants and additives with greater differences in surface tensions is required to develop a more rigorous and quantifiable theory for designing additives that improve boiling heat transfer.