Consider an ideal turbojet at flight conditions: To =220 K, PO = 20 kPa, and Mo= 0.8. Calculate and plot: 1) the specific thrust, 2) f, and 3) ISP versus the compressor stagnation pressure ratio (πc). Perform calculations for Tt, A=1600 K and 1800 K and for πc from 1 to 50. The fuel heat of combustion is hf= 42,800 kJ/kg. What πc maximizes thrust at the two peak stagnation temperatures?

When at a point two solid phase changes to one solid phase on cooling then it is known as a) eutectoid point b) eutectic point c) peritectic point d) peritectoid point

Which of the following is an easy way to remember the modified “x” tire rotation? a. nondrive wheels straight, cross the drive wheels b. drive wheels straight, cross the nondrive wheels c. drive wheels crossed, nondrive wheels straight d. drive wheels crossed, nondrive wheels crossed

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?