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Effect of refrigerant oil additive on R-134a and R-123 boiling heat transfer performance.

Impacto de aditivos en lubricantes sobre la transmisión de calor en la ebullición del R-134a y R-123.

Author(s) : KEDZIERSKI M. A.

Type of article: Periodical article

Summary

This article is the Spanish translation of an article published in the International Journal of Refrigeration (see Bulletin of the IIR, reference 2006-2852). This paper investigates the effect that an additive had on the boiling performance of an R-134a/polyolester lubricant (POE) mixture and an R-123/naphthenic mineral oil mixture on a roughened, horizontal flat surface. Both pool boiling heat transfer data and lubricant excess surface density data are given for the R134a/POE (98% mass fraction/2% mass fraction) mixture before and after use of the additive. A spectrofluorometer was used to measure the lubricant excess density that was established by the boiling of the R-134a/POE lubricant mixture before and after use of the additive. The measurements obtained from the spectrofluorometer suggest that the additive increases the total mass of lubricant on the boiling surface. The heat transfer data show that the additive caused an average and a maximum enhancement of the R-134a/POE heat flux between 5 and 22 kW/m2 of approximately 73 and 95%, respectively. Conversely, for nearly the same heat flux range, the additive caused essentially no change in the pool boiling heat flux of an R-123/mineral oil mixture. The lubricant excess surface density and interfacial surface tension measurements of this study were used to form the basis of a hypothesis for predicting when additives will enhance or degrade refrigerant/lubricant pool boiling.

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Pages: 12-30 (13 p.)

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Details

  • Original title: Impacto de aditivos en lubricantes sobre la transmisión de calor en la ebullición del R-134a y R-123.
  • Record ID : 2007-1459
  • Languages: Spanish
  • Source: IIF-IIR/Frío Calor Aire acond. - vol. 35 - n. 392
  • Publication date: 2007/05

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