Hot air flowing through a counter-flow double-pipe heat exchanger at a rate of 0.5 kg/s must be cooled from 250°c to about 100°c by water in the annulus initially at 15°c. the thermal resistance of the heat exchanger is 1.845x10 k/w. the specific heat capacities of the air and water may be taken as 1050 and 4190 j/kgk respectively. will this exchanger do the job when cooling water flow is 1.2 kg/s. use the ntu-effectiveness method.

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