Show that for a perfect gas the Mach number at the nose of the Fanno line (friction and no heating) and at the nose of the Rayleigh line (heating and no friction) is unity. The nose of these lines, examples of which are given in Figs. 3.6 and 3.7, is defined by ds/dT = 0. If a duct is sufficiently long that frictional effects (with no heating) have driven the Mach number at exit to unity, what would happen to the flow rate if, without changing the upstream values of p 0 and T0, the length of pipe suddenly increased?

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?