In a jet engine rotor the high pressure axial compressor rotates at a speed of 14750 rpm. the overall stagnation pressure ratio due to compression is 9.1. it was recorded that the air flows at a rate of 15.7 kg/s. the stagnation properties at the inlet are 205 kpa and 450k. the poly-tropic efficiency of the compressor is 92%. assume the mean radius of the compressor is constant and equal to 0.25m. calculate the total-to-total isentropic efficiency of the compressor. estimate the number of stages required, if the stage loading to be less than 0.4. why was the values of the area used to calculate t2?

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?

Compute the pressure drop of 30°c air flowing with a mean velocity of 8 m/s in a circular sheet-metal duct 300 mm in diameter and 15 m long. use a friction factor, f 0.02, and pair = 1.1644 kg/m a. 37.26 pa b. 25.27 pa n c. 29.34 pa d. 30.52 pa

Vibration monitoring this technique uses the noise or vibration created by mechanical equipment and in seme cases by plant systems to detemine their actual condtion. a)- true b)- false