الفهرس 
Introduction and literature reviewOnly 14 pages are availabe for public view
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Abstract
Forced convective heat transfer and friction factor for nanofluid flows inside circular horizontal tube with inserting helical tape, is experimentally studied under uniform heat flux. Experiments are conducted with adding nanoparticles (Al2O3) to water up to 0.3% by volume to obtain different concentrations of nanofluids. An experimental test loop equipped with the required measuring instruments is designed and constructed to assess the effects of nanoparticles concentration, mass flow rate, and applied heat rate on the convection heat transfer process and pressure drop. The measurements of temperature, flow rate, applied voltage to the heater and pressure DROP across the tube length are recorded and manipulated to calculate the convective heat transfer coefficient and friction factor, and in turns Nusselt number. The obtained experimental results showed that, the wall temperature is reduced by using nanofluid compared with pure water. Accordingly, the convection heat transfer coefficient increased when using nanofluid and it also increased with increasing heat rate and mass flow 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 convection heat transfer coefficient characterized by a swirling flow as a result of the secondary flow of the fluid flow inside tube with helical tape and the area of the tape inserted because the flow stream become longer. The average value for the thermal–hydraulic performance () for tube with inserting helical tape is 1.38 for water only, and 1.5 for nanofluid at concentration 0.2%. Comparison with the previous work shows fairly agreement. A correlation is obtained between Nusselt number and operating parameters. The comparison between the experimental correlation and the previous work is fairly in good agreement.