vol14no3pa8

In this research a theoretical study for laminar steady natural convection heat transfer through concentric horizontal annulus heated from inside, it’s contain two different fluids (p_r1:0.7, p_r2:7.0) for radius ratio (5) and for Gr numbers (102-105). A vorticity stream function formula was used in the numerical solution by transforming the governing differential equations into this formula, then turned into algebraic equations solved numerically using (Explicit Successive Over Relaxation finite deference method). To declare the movement of the fluids and the distribution of the temperatures through each of them counters for both streamlines and isotherms through the annulus were used, also the results contain calculating the distribution, of local Nu number along the internal cylinder inside the annulus, also a correlation was found to estimate the amount of heat transfer for both fluids. Through this research it’s found that two separating flows forming above and under the separating interface, also it’s found that the highest local Nu number accrue at the separating interface.