Ethanol is vaporized at 78 oc (hfg= 846 kj/kg) in a double-pipe parallel-flow heat exchanger at a rate of 0.04 kg/s by hot oil (cp= 2200 j/kg. k) that enters at 115 oc. if the heat transfer surface area and the overall heat transfer coefficients are 6.2 m2 and 210 w/m2.k, respectively, determine the outlet temperature and the mass flow rate of the oil using
(a) the lmtd method and
(b) the effectiveness method.

Asolid cylinder is concentric with a straight pipe. the cylinder is 0.5 m long and has an outside diameter of 8 cm. the pipe has an inside diameter of 8.5 cm. the annulus between the cylinder ad the pipe contains stationary oil. the oil has a specific gravity of 0.92 and a kinematic viscosity of 5.57 x 10-4 m2/s. most nearly, what is the force needed to move the cylinder along the pipe at a constant velocity of 1 m/s?