A cylinder, 6 mm in diameter, has a length of 24 mm. One end of the cylinder is open while all other surfaces have external insulation. The inside of the cylinder is diffuse and gray having an emissivity of 0.8 and a uniform temperature of 1000 K. Required:
a. Draw a sketch and state your assumptions.
b. Determine the radiant power leaving the open end of the cylinder.
c. Calculate the effective emissivity of the cylinder.

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?

An ideal otto cycle with air as the working fluid has a compression ratio of 8. the minimum and maximum temperatures in the cycle are 300 k and 1340 k. use constant specific heats at room temperature to determine (a) the amount of heat transferred to the air during the heat- addition kj/kg, (b) the thermal efficiency, and (c) the thermal efficiency of a carnot cycle ope limits. process, in rating between the same temperature

For a gate width of 2 m into the paper, determine the force required to hold the gate abc at its location.