Astraight fin is made from an aluminum alloy (k = 160 w/m-k) and is 0.5 cm in diameter and 30 cm long. the temperature at the base of the fin is 75oc and it is exposed to flowing air at 20oc with h = 20 w/m2-k. that is the rate of heat transfer from this pin?

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?

Find the kinematic pressure of 160kpa. for air, r-287 j/ kg k. and hair al viscosity of air at a temperature of 50°c and an absolute (10 points) (b) find the dynamic viscosity of air at 110 °c. sutherland constant for air is 111k

Along 8-cm diameter steam pipe whose external surface temperature is 900c connects two buildings. the pipe is exposed to ambient air at 70c with a wind speed of 50 km/hr blowing across the pipe. determine the heat loss from the pipe per unit length. (b) air at 500c enters a section of a rectangular duct (15 cm x 20 cm) at an average velocity of 7 m/s. if the walls of the duct are maintained at 100c. a) the length of the tube for an exit temperature of the air to be 40 0c. b)the rate of heat transfer from the air. c) the fan power needed to overcome the pressure drop in this section of the duct.