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Experimental Study on the Stability and Viscosity for the Blends of Functionalized MWCNTs with Refrigeration Compressor Oils

[ Vol. 14 , Issue. 3 ]

Author(s):

Ahmet Selim Dalkilic*, Omid Mahian, Bedri Onur Kucukyildirim, Aysegul Akdogan Eker, Tarik Hamza Ozturk, Chaiwat Jumpholkul and Somchai Wongwises*   Pages 216 - 226 ( 11 )

Abstract:


Background: Adding nanoparticles to working fluids such as compressor oil can be a solution to ameliorate the efficiency of refrigeration systems. Using the mixture of nanoparticles and oil that is called nanolubricant (or nanofluid) can augment the heat removal in refrigeration systems, however, in the same time, the pumping power will be increased as the viscosity of nanolubricants is higher than that of usual oils. Therefore, the measurement of nanolubricant viscosity is a prerequisite to estimating the pumping power in refrigeration systems.

Methods: Experiments section has been divided into three sections. First, the functionalization method of MWCNTs is presented. Then, the preparation of nanolubricants is explained. Finally, the viscosity measurement approach is explained.

Results: To increase the dispersibility of MWCNTs in compressor oil, functionalization of MWCNTs was done through attaching −OH and −COOH groups with the aid of 65 wt% nitric acid solution. It was observed that with increasing the viscosity of the base oil, the stability of MWCNTs based nanofluids improves. Then, the viscosity of nanofluids has been measured at a temperature range of 15°C to 50°C. It was found that at 50°C and mass concentration of 0.1%, viscosity enhances between 40 and 90%, depends on the type of base compressor oil.

Conclusion: Four correlations involving plane, paraboloid, Gaussian, and Lorentzian functions were suggested for the viscosity of nanolubricants. In the near future, it is expected from the results of this study that refrigeration systems will have included their Freon based refrigerants with nanoparticles.

Keywords:

Functionalized carbon nanotubes, nanofluids, viscosity, stability, compressor oil, fourier transform infrared spectroscopy.

Affiliation:

Heat and Thermodynamics Division, Department of Mechanical Engineering, Faculty of Mechanical Engineering, Yildiz Technical University (YTU), Yildiz, Besiktas, Istanbul 34349, Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi (KMUTT), Bangmod, Bangkok 10140, Materials Science and Manufacturing Technologies Division, Department of Mechanical Engineering, Yildiz Technical University (YTU), Yildiz, Besiktas, Istanbul 34349, Materials Science and Manufacturing Technologies Division, Department of Mechanical Engineering, Yildiz Technical University (YTU), Yildiz, Besiktas, Istanbul 34349, Heat and Thermodynamics Division, Department of Mechanical Engineering, Faculty of Mechanical Engineering, Yildiz Technical University (YTU), Yildiz, Besiktas, Istanbul 34349, Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi (KMUTT), Bangmod, Bangkok 10140, Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi (KMUTT), Bangmod, Bangkok 10140

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