Analysis of variance of nanofluid heat transfer data for forced convection in horizontal spirally coiled tubes

Document Type : Full Lenght Research Article


1 Young Researchers and Elite Club, Karaj Branch, Islamic Azad University, Karaj, Iran

2 Young Researchers and Elite Club, Semnan Branch, Islamic Azad University, Semnan, Iran

3 Solar Energy Group, Energy Department, Materials and Energy Research Center(MERC)


In the present study, an experimental study is carried out to investigate the effect of adding Al and Cu nanoparticles to the base fluid (water) on the heat transfer rate in a spirally coiled tube. The spirally coiled tube is fabricated from the straight copper tube with the inner and outer coil diameters of 100 and 420 mm, respectively. The experiments have been done for water and two types of nanofluids with different concentrations and at various operational conditions. The Thermal conductivities of these fluids have been measured experimentally. The results show that thermal conductivity of Cu-water nanofluid is about 18 % more than Al-water nanofluid at 2.23 vol. %. The forced convective heat transfer has been studied by changing the wall temperature, concentration, Gz number, and nanofluid type. The Results indicate that nanofluids have significant positive effect on convective heat transfer coefficient. Also, the Nusselt number increases with an increase in the Gz number. The most important effective parameters on the heat transfer are found to be the Gz number based on the analysis of variance (ANOVA) method. Based on the statistical analysis, a new correlation for the Nusselt number is introduced.


Main Subjects

[1]     Naphon P, Wongwises S. An experimental study the in-tube convective heat transfer coefficients in aspiral-coil heat exchanger. IntCommun Heat Mass Transfer 29, (2002) 797–809.
[2]     J.C. Ho, N.E. Wijeysundera, S. Rajasekar, T.T. Chandratilleke,Performance of a compact spiral coil heat exchange, Heat RecoverySystem nas CHP 15, (1995) 457–468.
[3]      S. Rahul, S.K Gupta, P.M.V Subbarao, An experimental study for estimating heat transfer coefficient from coiled tube surfaces in cross-flow of air, Proceeding of the third ISHMT-ASME heat and mass transfer conference and Fourth National heat and mass transfer conference, India, December (1997) 381-385.
[4]     M.K. Khan, R. Kumar, P.K. Sahoo, An experimental studyof the flow of R-134a inside an adiabatic spirally coiledcapillary tube, International Journal of Refrigeration (2008); doi:10.1016/j.ijrefrig. 2008.01.008  
[5]     C.E Kalbe and J.D. Seader, Fully developed viscous-flow heat transfer in curved circular tubes with uniform wall temperature, AIChe Journal, 20, (1974) 340-346.
[6]     M.K. Mittal, R. Kumar, A. Gupta, Numerical analysis of adiabatic flow of refrigerantthrough a spiral capillary tube, International Journal of Thermal Sciences 48, (2009) 1348-1354
[7]     M. Mirzaei, M. Dehghan, Investigation of flow and heat transfer of nanofluid in microchannel with variable property approach, Heat Mass Transfer 49 (2013) 1803-1811.
[8]     M. T. Jamal-Abad, A. H. Zamzamian, M. Dehghan, Experimental studies on the heat transfer and pressure drop characteristics of Cu-water and Al-water nanofluids in a spiral coil, Experimental Thermal and Fluid Science 47 (2013) 206-212.
[9]     M.T. Jamal-Abad, M. Dehghan, S. Saedodin, M.S. Valipour, A. Zamzamian, An Experimental investigation of rheological characteristics of non-Newtonian nanofluids, J. Heat Mass Trans. Res. 1 (2014) 17-23.
[10]  Yu, W., France, D. M., Routbort, J. L., Choi, S. U. S., Review and Comparison of Nanofluid Thermal Conductivity and Heat Transfer Enhancements. Heat Transfer Engineering. 29(5) (2008) 432-460.
[11]  M. Dehghan, M. Daneshipour, M.S. Valipour, R. Rafee, S. Saedodin, Enhancing heat transfer in microchannel heat sinks using converging flow passages, Energy Conversion and Management 92 (2015) 244-250.
[12]  Milad Tajik Jamal-Abad,A. Zamzamian,E. Imani, M. Mansour, Experimental Study of the Performance of a Flat-Plate Collector Using Cu–Water Nanofluid, Journal of Thermophysics and Heat Transfer 27(4) (2013) 756-760.
[13]  A. Zamzamiana, M.T Jamal-Abad, Factor  Effect  Estimation  in  the  Convective  Heat  Transfer  Coefficient  Enhancement of Al2O3 /EG Nanofluid  in a Double-pipe Heat Exchanger, IJE TRANSACTIONS B: Application   Vol. 26 (8), (2013) 837-844.
[14]  V. Kubair and N. R. Kuloor, Heat transfer to Newtonian fluids in spiral coils at constant tube walltemperature in laminar flow, Indian J. Technol., Vol. 3, (1965) 144 -146.
[15]  Das, S.K., N. Putra, P. Thiesen, and W. Roetzel, Temperature dependence of thermal conductivity enhancement for nanofluids. Journal of Heat Transfer- Transactions of the Asme, 125(4), (2003) 567-574.
[16]  Xie, H.Q., J.C. Wang, T.G. Xi, Y. Liu, F. Ai, and Q.R. Wu, Thermal conductivity enhancement of suspensions containing nanosized alumina particles. Journal of Applied Physics, 91(7), (2002) 4568-4572.
[17]  Eastman, J.A., U.S. Choi, S. Li, L.J. Thompson, and S. Lee, Enhanced thermal conductivity through the development of nanofluids. Materials Research Society Symposium Proceedings, 457(Nanophase and Nanocomposite Materials II), (1997) 3-11.
[18]  Lee, S., S.U.S. Choi, S. Li, and J.A. Eastman, Measuring thermal conductivity of fluids containing oxide nanoparticles. Journal of Heat Transfer-Transactions of the Asme, 121(2), (1999) 280-289.