mojtaba daneshi - Department of Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
nader dizadji - Department of Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
mohammad najafi - Department of Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran

In this experimental study of natural convective heat transfer in a Hele-Shaw cell and flow pattern analysis is performed. For this purpose Hele-Shaw cell with dimensions of 20×20 cm plus temperature and flow rate measurement tools built into the cell with the base fluid (water) and nanofluid (water-Copper ) is filled. Nano copper in water-based fluid in three different concentrations of 0.01, 0.02 and 0.04% by volume and made the two-step method for homogenization of physical methods (mixing and vibration by Ultrasonic probe and Ultrasonic bath) and chemical methods (the active surface) was used. Tests on five heat flux, in two different discharges and in three different angles relative to ground level (zero degree, 45 degree and 90 degree) has been done. On this issue, the coefficient of heat transfer, Nusselt and Rayleigh number calculated and how the flow pattern is examined. To view the flow pattern in the display device with Hele-Shaw cell from c-etching method used. Using data obtained from Rayleigh number range between 103 to 105 and the range of heat transfer is between 8 to 105, the highest number in heat flux heat transfer in nanofluids 494 W and is water-copper with 0.04% vol. Analysis of results and calculate the heat transfer coefficient of nanofluids studied for an increase of over 32% compared to pure water. The results show that with increasing discharge, heat transfer coefficient increases. Values are determined with a maximum uncertainty of results is equal to ± 2.2.

Natural convection, Nanofluid, Fluid Flow, Hele-Shaw cell