THE LOCAL HEAT TRANSFER COEFFICIENT AT THE BOILING OF THE ISOBUTANE/ MINERAL OIL SOLUTION FLOW IN THE PIPE
DOI:
https://doi.org/10.15673/0453-8307.2/2014.32589Keywords:
Heat transfer coefficient – Real work fluid –Boiling – Isobutan – Refrigerant/oil solution – Concentration.Abstract
Experimental data for refrigerant R600a mixed with the compressor mineral naphthenic oil ISO VG 15 boiling in the smooth small-diameter (5.4 mm) tube are reported. The tests were conducted at the inlet pressure psuc in the range from 62.3 to 82.2 kPa, heat flux from 2754 to 4105 W/m2, mass velocity varied between 11.90 to 18.54 kg/(m2∙s) and oil concentrations at the inlet to the evaporator from 0.25 to 0.5 % by mass. The results of the research of the local heat transfer coefficient at the boiling of the isobutane/compressor oil solution flow are given in the paper. It is shown that the substantial reduction of heat transfer coefficient was observed at high concentrations of oil. In addition, during the boiling of the refrigerant/oil solution the heat transfer coefficient in the lower part of the pipe is decreasing with mass velocity increasing.
References
REFERENCES
Thome J. R. Boiling of new refrigerants: A state-of-the-art review // International Jornal of Refrigeration-Revue Internationale du Froid. – 1996. – v 19. – p. 435 – 457.doi: 10.1016/s0140-7007(96)00004-7
2.Filho E.P., Cheng L., Thome J.R. Flow boiling characteristics and flow pattern visualization of refrigerant/lubricant oil mixtures // International Jornal of Refrigeration. — 2009. — v 32. — p. 185–202.doi: 10.1016/j.ijrefrig.2008.06.013
3.Hu H., Ding G., Huang X. Measurement and correlation of flow-boiling heat transfer of a R410a/oil mixture inside a 4.18 mm straight smooth tube // HVAC&R Research. — 2009. — v 15. — p. 287–314.doi: 10.1080/10789669.2009.10390838
4.Wei W., Ding G., Hu H. Influence of lubricant oil on heat transfer performance of refrigerant flow boiling inside small diameter tubes. Part 1: Experimental study. // Experimental Thermal and Fluid Science. — 2007. — v 32. — p. 67–76.doi: 10.1016/j.expthermflusci.2006.10.012
5.Eckels, Doerr S., Pate T.M., In-tube heat transfer and pressure drop of R134a and ester lubricant mixtures in a smooth tube and a micro-fin tube: part 1 – evaporation. // ASHRAE. — 1994a. — v 100. — p. 265–282.
6.Schlager L.M., Pate M.B., Bergles A.E. Performance predictions of refrigerant–oil mixtures in smooth and internally finned tubes, part I: literature review // ASHRAE Trans. — 1990a. — v 96. — p. 160–169.
Rabochie tela parokompressornih holodilnih mashin: svoistva, analiz, primenenie: monogr. / V.P. Zhelezny, Y.V. Semenyuk – Odessa: Fenics, 2012. – 420 s.
8.Wen M.Y., Ho C.Y., Jang J.K. Boiling heat trandfer of refrigerant R600a/R290-oil mixtures in the serpentine small-diameter U-tubes // Applied Thermal Engineering. — 2007. — v 27. — p. 2353–2362.doi: 10.1016/j.applthermaleng.2007.03.017
9.Shen B., Groll E. Critical literature review of lubricant influence on refrigerant heat transfer and pressure drop. Final report // HVAC&R Research. — 2003. — p. 199.
Zhelezny V.P., Nichenko S.V., Semenyuk Yu. V., Skripov P. V. Experimental investigation of the enthalpy of isobutane−compressor oil solutions // J. Chem. Eng. Data. — 2010. — v 55. — p. 1322–1326.doi: 10.1021/je900647s
McLinden, M. O., Klein, S. A., Lemmon, E. W. and Peskin, A. P. G. 2003,NIST Standard Reference Database 23,NIST Thermodynamic Properties of Refrigerants and Refrigerants Mixtures Database (REFPROP), Version 7.1 (Gaithersburg: National Institute of Standard and Technology).
Kattan N., Thome J.R., Favrat D. Flow boiling in horizontal tubes: Part 1 – development of a diabatic two-phase flow pattern map // Journal of heat transfer-Transactions of the ASME. — 1998a. — v 120. — p. 140–147.doi: 10.1115/1.2830037
Hambraeus K. Heat transfer of oil-comtaminated HFC134a in a horizontal evaporator. // International Jornal of Refrigeration-Revue Internationale du Froid. — 1995. — v 18. — p. 87–99.doi: 10.1016/0140-7007(94)00004-h
Cho, Tae K. Condensation heat transfer for R22 and R407C refrigerant-oil mixtures in a microfin tube with a U-bend // International Journal of Heat and Mass Transfer. — 2001. — v 44. — p. 2043–2051.doi: 10.1016/s0017-9310(00)00253-2
