) Air at 20 kPa and 5 °C enters a 1.5 cm diameter tube at a uniform velocity of 1.5 m/s. The tube walls are maintained at a uniform temperature of 45 °C. Estimate the distance from the entrance at which the flow becomes fully developed. For air, use = 0.25 kg/m3 , µ = 1.746 × 10−5 kg/(m ∙ s), k = 0.0247 W/(m ∙ K), cp = 1004.47 /(kg ∙ K), Pr = 0.709

Fluids at rest possess no flow energy. a)- true b)- false

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater