convective heat transfer coefficient
Hello everybody! I want to calculate the convective heat transfer coefficient of a cylinder with Fluent.  diameter of the cylinder : d = 0,1524 m  temperature of the cylinder: Tcyl = 273,15 K  temperature of the airflow: Ta = 268,30 K  air velocity : u = 90 m/s  air pressure : p = 100 000 Pa  y+ : between 20 and 50
at "XY Plot"  "Wall Fluxes"  "surface heat coefficient" I receive a value hc=90 W/m²K at the stagnation point. In an article about NASAs LEWICE, they maintain a value of hc=170 W/m²K. In another article, there is a equation für the coefficient for a cylinder: hc = thermal conductivity * Nusselt number/diameter with Nusselt Number = 1,14 * (Prandtl^0,4)*(Reynold^0,5); there you get a value hc = 165 W/m²K Do I have to consider something tricky with fluent because my value is pretty low? 
Re: convective heat transfer coefficient
Heat transfer is very sensitive to the y+ value used. You are probably going to need to reduce your y+ down substantially to get a good value (possibly down as low as 0.10.2). No trickery involved, just getting good resolution of the temperature gradient.

Re: convective heat transfer coefficient
you should check the reference value for temperature!

Re: convective heat transfer coefficient
Dear sir,
I want to calculate the convective heat transfer coefficient of a cylinder casing with temperature 200 deg c, tempearature of air flow outside the casing will be 45 deg c with humidity 95%, please assist me in this regard to proceed with calculation by providing reference material or sample calculations. regards, p k saloni 
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