Conjugate conduction and natural convection heat transfer in a cavity filled with nanofluid and purefluid which separated with an obstacle

The purpose of present paper is numerical study of the effect of pure fluid (water, air and ethilen glicon) on flow field and heat transfer rate of a cavity contatining nano fluid and pure fluid which separated with an obstacle. we used water-copper oxide as nano fluid. governing equations are derived based on volume controll method and solved base on SIMPLE method together. results show that, increasing Grashof number will cause rise of flow speed and heat transfer rate in cavity. in ( , ) Grashof numbers, conduction is the dominated heat transfer and with increasement of Grashof number ( , ), mechanism changes from conduction to convection. in cavity containing air-nano fluid, the strength of vorticities in cavity containg air () is greater than the nano fluid one (). while in the cavity containing nano fluid-ethilen glicon (), vorticity strength is greater in cavity containing nano fluid (). in low Grashof numbers, heat transfer rate on hot wall, while the pure fluid is air (95.77%), is greater than ethilen glicon (70.34%) and ethilen glicon is greater than water (50.14%). in high Grashof numbers heat trasnfer rate on hot wall, while the pure fluid is ethilen glicon (67.33%), is greater than air (56.41%) and air is greater than water (50.93%). while in all Grashof numbers heat transfer rate on cold wall,