Prototypes do all of the following except A)allow for experimentation with new ideas.
B) provide a way to test improvements and fix flaws.
C) create a physical model in the early design stages
D) remain unchanged throughout the design process

Apreheater involves the use of condensing steam at 100°c on the inside of a bank of tubes to heat air that enters at 1 atm and 25°c. the air moves at 5 m/s in cross flow over the tubes. each tube is 1 m long and has an outside diameter of 10 mm. what is the minimum value of nl needed to achieve an outlet temperature of t 75 c? what is the corresponding pressure drop across the tube bank?