3000 kg of water is heated per hour from 30 to 70 0C by pumping it through a certain heated section of a 25 mm diameter tube. If the surface of the heated section is maintained at 110 0C, estimate length of the heated section and the rate of heat transfer from the tube to water. The thermo-physical properties of water are: rho = 971.6 kg/m3 ; μ = 0.355 x 10-3 kg/m-s; k = 0.667 W/m-deg; Cp = 4195 J/kg-deg. Use Nu = 0.023 (Re) 0.8 (pr) 0.4

Ahot wire operates at a temperature of 200°c while the air temperature is 20°c. the hot wire element is a tungsten wire of 5 um diameter and 2 mm in length. plot using excel current, heat transfer and heat generated by the wire for air velocity varying from 1-10 m/s in steps of lm/s? matlab the sensor voltage output, resistance, or assume nu 0.989 re033pr13 take air properties at tr (200°c20°c)/2 = 110°c properties of tungsten: c 0.13 kj/kg. k 3 p 19250 kg/m k (thermal conductivity) = 174 w/m. k