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Heat and mass transfer from or to a horizontal moving water film to airflow flowing over the film inside a rectangular duct wind tunnel is investigated, experimentally. To perform the experimental study for this phenomenon air flows inside a rectangular duct over a moving water film flow inside the duct, which is fixed in the floor of the tunnel. Therefore, some of the water film is evaporated from the water surface to the air flowing over it. The following measurements for velocity of moist air and water, temperature, humidity, are taken at five positions along test section and upstream of the water panel. Also, the amount of water evaporated through each experiment is measured. The results show that, Nusselt and Sherwood numbers increase with increasing Reynolds number. Comparison between the obtained results and the previous works show good agreement.

Heat and mass transfer between a horizontal moving water film and air flowing over the film is theoretically investigated. In the present theoretical model, the flow of air over the moving water film is assumed to be laminar and steady in Cartesian coordinates. The governing equations are the continuity, momentum, energy and concentration equations. These governing equations set of equations to determine the distribution of the dimensionless velocity, temperature are in a dimensionless form. By introducing new proper independent and dependent variables, the governing equations are transformed to a set of dimensionless differential equations. A computer program in FORTRAN language is developed to solve this and concentration. Also, local values of Nusselt and Sherwood numbers for different values of Reynolds number are calculated. Comparison between the obtained results and the previous works show good agreement. The results show that, Nusselt and Sherwood numbers increase with increasing Reynolds number.

The study of natural convection from a heat source located at the bottom of partially top vented enclosure is presented. Air cooling for electronic component situated at the bottom of a top vented enclosure is studied theoretically. The flow is assumed to be laminar, steady and of constant physical properties. The process is described by continuity, momentum and energy partial differential equations, which are be expressed in Cartesian coordinates system. Due to the nature of the studied problem and with proper transformation of the problem dependent and independent variables, these governing equations are transformed to a set of dimensionless partial differential equations. This set of differential equations is transformed to set of difference equations by the implantation of finite difference technique. Accordingly, one can obtain the solutions for this problem, which are obtained by application of the well known Gauss Siedel iteration method. A computer program is developed to solve the present proposed mathematical model. According to this solution, the values of Nusselt number, for different values of Rayleigh number are obtained. Comparisons between the present obtained results and those results obtained in previous theoretical results are performed for parametric variations of the vent opening size and shape. Also a correlation for Nusselt number as a function of Rayleigh number and equivalent diameter of the vent is proposed.

Forced convection heat transfer and friction factor for nanofluid flows inside circular horizontal tube with and without inserting helical tape, was experimentally studied. Electric heater was wrapped around the outer surface of the tube to obtain a constant and uniform heat flux at the tube wall. Experiments are conducted with adding nano-particles (AI2O3) to water up 10, 2% by volume 10 obtain diffrerent concentrations of nanonfluids. An experimental test loop equipped with the required measuring instruments was designed and constructed to assess the effects of nano-particles concentration, mass flow rate, and applied heat flux on the convection heal transfer process and pressure drop. The tested tube fitted with screw helical tape inserts to evaluate its effects on heal transfer rate and friction factor with nanofluid as the working fluid compared with pure water. The measurements of temperature, now rate, applied volt and pressure drop are recorded and manipulated to calculate the convection heat transfer coefficient and friction factor. The obtained experimental results show that, wall temperature was reduced by using nanofluid compared with pure water. Accordingly. the convection heal transfer coefficient;' increased when using nanofluid and increased also with increasing heat flux and mass now rate (Reynolds number). Higher rates of heat transfer and pressure drop are obtained from the tube fitted with screw helical tape insert compared to flow in a plain/tube under similar conditions. This improvement in the heat transfer coefficient characterized by a swirling flow as a result of the secondary flow of the fluid flow inside tube with helical tape. The average value for the thermal-hydraulic performance(ŋ) for tube with inserting helical tape was 1.4 for water only , and 1.8 for nanofluid at concentration 0.8% comparison with the previous work gave good agreement.

Thermal performance of a flat heat pipe cooling system is experimentally investigated. Pure water and Al2O3-water based nanofluids are used as working fluids. An experimental setup is designed and constructed to study its performance under different operating conditions. The effect of working fluid, filling ratio, volume fraction of nano-particle in the base fluid, and heat input rate on the average heat transfer coefficient and in turn the average Nusselt number are investigated. Total thermal resistance of the heat pipe for pure water and Al2O3-water based nanofluid are also predicted. Correlation is obtained to predict the influence of Prandtl number, filling ratio and dimensionless heat coefficient, Kq for Nusselt number. Results showed that the average heat transfer coefficient, using Al2O3-water based nanofluid enhanced by 10.5% up to 37% compared to that of pure water, depending on filling ratio and volume fraction of nano-particles in the base fluid. The experimental data are compared with the available literature and discrepancies between results are discussed.