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Abstract
The Nano materials play a very important role in the heat transfer enhancement. An experimental investigation has been done to understand the behaviors of nano and micro materials on critical heat flux. Pool boiling experiments have used for several concentrations of nano and micro particles on a 0.4 mm diameter nickel chrome (Ni-Cr) wire heater which is heated electrically at atmospheric pressure. Zinc oxide(ZnO) and silica(SiO2) were used as a nano and micro fluids with concentrations (0.01,0.05,0.1,0.3,0.5,1 g/L), a marked enhancement in CHF have been shown in the results for nano and micro fluids for different concentrations compared to distilled water. The deposition of the nano particles on the heater surface was the reason behind the enhancement of the wettability of the surface which will increase the CHF, this nano particles deposition will form a porous layer and the mechanism of the formation of this layers is that as vapor bubbles grow, the evaporating liquid in the micro layer leaves behind Nano particles which then will be concentrated at the base of the bubble to form this pours layer. The higher wettability can produce CHF enhancement, the enhancement ratio of Nano fluid is observed to be higher than that of micro fluid, the optimum enhancement ratios of nano fluid is (1 g/l) which observed to be 9.2 % for ZnO and 8.7% for Sio2, and also (1 g/l) for micro fluid which observed to be 8.1%for ZnO and 7.4%for SiO2.
References
Eastman, J. A., Choi, S. U. S., Li, S., Yu, W., and Thompson, L. J., "Anomalously Increased Effective Thermal Conductivities of Ethylene Glycol- Based Nano fluids Containing Copper Nanoparticles", Appl. Phys. Lett., 78, pp. (718–720), 2001.
Wen, D., and Ding, Y., "Experimental Investigation into Convective Heat Transfer of Nano fluids at the Entrance Region Under Laminar Flow Conditions", Int. J. Heat Mass Transfer, 47, pp. (5181–5188), 2004.
Barber, J., Brutin, D., and Tadrist, L., "A review on boiling heat transfer enhancement with Nano fluids'', Nano scale Research Letters, 2:280, 2011.
Cooke, D., "Experimental study of pool boiling heat transfer enhancement over micro channeled surfaces", M. Sc Thesis, Rochester Institute of Technology, Rochester, New York, 2011.
Vassallo, P., Kumar, R., and D’Amico, S.," Pool boiling heat transfer experiments in silica-water Nano fluids", Int. J. Heat Mass Transfer, 47, pp. (407–411), 2004.
Madhusree, K., and Dey, K.T., "Investigations on the pool boiling heat transfer and critical heat flux of ZnO-ethylene glycol Nano fluids", Applied Thermal Engineering ,37, pp. (112-119), 2012.
Milanova, D., and Kumar, R.," Role of ions in pool boiling heat transfer of pure and silica Nano fluids", Appl. Phys. Lett ,87, pp. (185–194), 2005.
Bang, C. I., and Chang, H.S., " Boiling heat transfer performance and phenomena of Al2O3-water Nano fluids from a plain surface in a pool", Int. J. Heat Mass Transfer, 48, pp. (2407–2419), 2005.
Kim, J.S., Bang, I.C., Buongiorno, J., and Hu, L.W., " Effects of nanoparticle deposition on surface wettability influencing boiling heat transfer in Nano fluids", Appl Phys Lett, 89, 153107, pp. (1-3), 2006.
Bergman, L. T., Lavine, S. A., INCROPERA, P. F., and Dewitt, P. D.," Fundamentals of Heat and Mass Transfer" ,7th ed,2011.
Vassallo, P., Kumar, R., and D’Amico, S.," Pool boiling heat transfer experiments in silica-water Nano fluids", Int. J. Heat Mass Transfer, 47, pp. (407–411),2003.
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