Hot water (cph = 4188 J/kg∙K) enters a thin-walled double-pipe counterflow heat exchanger at 2.5 kg/s and 100°C. The overall heat transfer coefficient and the surface area are 1000 W/m2 ∙K and 21 m2 , respectively. For the cold stream, cold water (cpc = 4178 J/kg∙K) enters the heat exchanger at 5 kg/s and 20°C. (a) Determine the heat transfer rate for the heat exchanger (in W)

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