Nitrogen gas enters a turbine operating at steady state through a 2-in.-diameter duct with a velocity of 200 ft/s, a pressure of 50 lbf/in.2 , and a temperature of 1000R. At the exit, the velocity is 2 ft/s, the pressure is 20 lbf/in.2 , and the temperature is 700R. Heat transfer from the surface of the turbine to the surroundings occurs at a rate of 16 Btu per lb of nitrogen flowing. Neglecting potential energy effects and using the ideal gas model, determine the power developed by the turbine, in horsepower

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

Manometers are good examples of measuring instruments, nowadays they are not as common as before. a)-capacitive probe gauges b)-gravitational gauges deformation ) gauges d)-digital gauges