During steady-state operation, a parallel –shaft transmission receives 600 kw through the high-speed shaft, but owing to friction and other irreversibilities, delivers 588 kw through the low-speed shaft. the transmission is cooled on its outer surface according to:

q = -ha(ttrans – t.)

where h is the heat transfer coefficient, a is the outer surface area, ttrans is the uniform temperature of the outer surface of the transmission and to is the uniform temperature of the surroundings away from the immediate vicinity of the gearbox.

evaluate the rate of entropy production for :

(a) the gearbox system
(b) an enlarged system consisting of the gearbox and enough of its surroundings that the heat transfer occurs at t0.

let h=0.17 kw/m2-k, a=1.8 m2 and t0=239 k.

Apump is used to circulate hot water in a home heating system. water enters the well-insulated pump operating at steady state at a rate of 0.42 gal/min. the inlet pressure and temperature are 14.7 lbf/in.2, and 180°f, respectively; at the exit the pressure is 60 lbf/in.2 the pump requires 1/15 hp of power input. water can be modeled as an incompressible substance with constant density of 60.58 lb/ft3 and constant specific heat of 1 btu/lb or. neglecting kinetic and potential energy effects, determine the temperature change, in °r, as the water flows through the pump.

Courses that are developed by subject matter experts, internal or extemal to the college or university. these programs are marketed by the school (clo2) marks a)-vocational schools b)-vendor training c)-colleges & universities d)-continuing education programs

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w