Consider a flat plate with the surf-ace heat flux specified as ,, l2O W/m2 when 0 { x { 15 cm, 4,, : ll0 W/m2 when x ) 15 cm. Air at atmospheric pressure and 20"C flows over this plate at 3 m/s. Estimate the variation of wall temperature with the distance x fiom the leading edge in the laminar boundary layer region, and evaluate the wall temperature numerically at 30 cm.

On a average work day more than work place firs are reorted

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?

Calculate the bore of a cylinder that has a stroke of 18 inches and an extension time of 6 seconds at a flow rate of 4 gal/min.