## THERMAL SCIENCE

International Scientific Journal

### NUMERICAL AND EXPERIMENTAL INVESTIGATION OF HEAT TRANSFER OF ZNO/WATER NANOFLUID IN THE CONCENTRIC TUBE AND PLATE HEAT EXCHANGERS

**ABSTRACT**

The plate and concentric tube heat exchangers are tested by using the water-water and nanofluid-water streams. The ZnO/Water (0.5%v/v) nanofluid has been used as the hot stream. The heat transfer rate omitted of hot stream and overall heat transfer coefficients in both heat exchangers are measured as a function of hot and cold streams mass flow rates. The experimental results show that the heat transfer rate and heat transfer coefficients of the nanofluid in both of the heat exchangers is higher than that of the base liquid (i.e., water) and the efficiency of plate heat exchange is higher than concentric tube heat exchanger. In the plate heat exchanger the heat transfer coefficient of nanofluid at mcold = mhot = 10 gr/sec is about 20% higher than base fluid and under the same conditions in the concentric heat exchanger is 14% higher than base fluid. The heat transfer rate and heat transfer coefficients increases with increase in mass flow rates of hot and cold streams. Also the CFD1 code is used to simulate the performance of the mentioned heat exchangers. The CFD results are compared to the experimental data and showed good agreement. It is shown that the CFD is a reliable tool for investigation of heat transfer of nanofluids in the various heat exchangers.

**KEYWORDS**

PAPER SUBMITTED: 2009-11-03

PAPER REVISED: 2010-03-03

PAPER ACCEPTED: 2010-04-11

**THERMAL SCIENCE** YEAR

**2011**, VOLUME

**15**, ISSUE

**Issue 1**, PAGES [183 - 194]

- Gut, J. A.W. et al., Thermal model validation of plate heat exchangers with generalized configurations, Chemical Engineering Science 59 (2004) pp.4591 - 4600
- Vlasogiannis, P. et al., Air-water two-phase flow and heat transfer in a plate heat exchanger, International Journal of Multiphase Flow 28 (2002)pp.757-772
- Jassim , E. W. Newell, T. A. Chato, J. C., Refrigerant pressure drop in chevron and bumpy style flat plate heat exchangers, Experimental Thermal and Fluid Science 30 (2006) pp.213-222
- Dwivedi, A. K. Das, K. S., Dynamics of plate heat exchangers subject to flow variations, International Journal of Heat and Mass Transfer 50 (2007)pp. 2733-2740
- . Maiga, S. E. B. et al., Heat transfer behavior of nanofluids in a uniformly heated tube, Superlattices and Microstructures, 35(2004)pp.543-557.
- . Xuan, Y. and Roetzel, W. Conceptions of heat transfer correlations of nanofluids, International Journal of Heat and Mass Transfer, 43(2000)pp. 3701-3707.
- . Abu-Nada, E. Masoud, Z. and Hijazi, A. Natural convection heat transfer enhancement in horizontal concentric annuli using nanofluids, International Journal of Heat and Mass Transfer, 35(2008) pp.657-665.
- . Trisakasri, V. and Wongwises, S., Critical review of heat transfer characteristic of nanofluids, Renewable and sustainable energy reviews, 11(2007) pp. 512-523.
- . Daungthongsuk, W. and Wongwises, S., A critical review of convective heat transfer of nanofluids, Renewable and sustainable energy reviews, 11(2007) pp.797-817.
- . Jung, J. Y. Oh, H. S. and Kwak, H. Y., Forced convective heat transfer of nanofluids in micro channels, International Journal of Heat and Mass Transfer, 52(2009) pp.466-472.
- . Li, Q. Xuang, Y., Convective heat transfer and flow characteristic of Cu-Water nanofluid, Science in China, Series E, 45, 4 (2002), pp.408-416.
- Choi S. U. S., Enhancing thermal conductivity of fluids with nanoparticles. In: D.A. Siginer and H.P. Wang, Editors, Developments and Applications of Non-Newtonian Flows, FED, vol. 231/MD vol. 66, ASME, New York (1995), pp. 99-103.
- . Yang, Y. et al., Heat transfer properties of nanoparticle in fluid dispersions in laminar flow, International Journal of Heat and Mass Transfer, 48(2005) pp.1107-1116.
- Wen D, Ding Y., Experimental Investigation into Convective Heat Transfer of Nanofluids at the Entrance Region under Laminar Flow Conditions. International Journal of Heat and Mass Transfer 47 (2004) pp.5181-5188
- Pantzali, M.N. Mouza, A. A. Paras, S. V., Investigating the efficacy of nanofluids as coolants in plate heat exchangers (PHE), Chemical Engineering Science 64 (2009) pp.3290 -- 3300
- Duangthongsuk, W. Wongwises, S., Heat transfer enhancement and pressure drop characteristics of TiO2-water nanofluid in a double-tube counter flow heat exchanger, International Journal of Heat and Mass Transfer 52 (2009) pp.2059-2067
- Mapa, L. B. Mazhar, S., Heat transfer in the mini heat exchanger using nanofluids, American Society for Engineering Education, 2005 IL/IN Sectional Conference, April 1-2, 2005 - Northern Illinois University, DeKalb, Illinois
- Rennie, T. J. Raghavan, V. G. S., Numerical studies of a double-pipe helical heat exchanger, Applied Thermal Engineering 26 (2006) pp.1266-1273
- Kanaris, A. G. Mouza, A. A. Paras, S. V., Flow and Heat Transfer Prediction in a Corrugated Plate Heat Exchanger using a CFD Code, Chemical Engineering Technology, 29 (2006), 8, pp.923-930.
- Galeazzo, F. C. C. et al., Experimental and numerical heat transfer in a plate heat exchanger, Chemical Engineering Science 61 (2006) pp.7133 - 7138
- Grijspeerdt, K. Hazarika, B. Vucinic, D., Application of computational fluid dynamics to model the hydrodynamics of plate heat exchangers for milk processing, Journal of Food Engineering 57 (2003) pp.237-242
- Fernandes Carla S. et al., Laminar flow in chevron-type plate heat exchangers: CFD analysis of tortuosity, shape factor and friction factor, Chemical Engineering and Processing 46 (2007) pp.825-833
- Pantzali, M. N. et al., Effect of nanofluids on the performance of a miniature plate heat exchanger with modulated surface, International Journal of Heat and Fluid Flow 30 (2009) pp.691-699
- . Patankar, S. V., "Numerical heat transfer and fluid flow", Hemisphere Publishing Corporation, Taylor and Francis Group, New York, 1980.
- . Versteeg and Malasekera, "An introduction to Computational Fluid Dynamics", McGraw Hill, New York, 1960.
- . Drew, D. A. and . Passman, S. L., Theory of multicomponent fluids, Springer, Berlin, (1999).
- . Yu, W. Choi, U. S. The role of international layers in the enhanced thermal conductivity of nanofluids: A renovated Maxwell model, Journal of Nanoparticle Research, 5(2003) pp.167-171.
- . Namburu, P. K., Numerical study of turbulent flow and heat transfer characteristics of nanofluids considering variable properties, International Journal of Thermal Science, 48 (2009)pp.290-302.
- . Akbarnia, A. Behzadmehr, A., Numerical study of laminar mixed convection of a nanofluid in horizontal curved tubes, Applied Thermal Engineering, 27(2007) pp.1327-1337.
- . Xuan, Y. Li, Q., Investigation on convective heat transfer and flow features of nanofluids, ASME Journal of Heat Transfer, 125(2003) pp.151-155.
- Gut, J. A. W. Pinto, J. M., Modeling of plate heat exchangers with generalized configurations, International Journal of Heat and Mass Transfer 46 (2003) 2571-2585
- Lyytikainen, M. Hamalainen,T. Hamalainen, J., A fast modelling tool for plate heat exchangers based on depth-averaged equations, International Journal of Heat and Mass Transfer 52 (2009) pp.1132-1137