Aspherical, underwater instrument pod used to make soundings and to measure conditions in the water has a diameter of 85mm and dissipates 300 w.

a. estimate the surface temperature of the pod when suspended in a bay where the current is 1 m/s and the water temperature is 15 c.

b. inadvertenly, the pod is hauled out of the water and suspended in ambient air without deactivating the power. estimate the surface temperature of the pod if the air temperature is 15 c and the wind speed is 3 m/s.

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?

Determine whether or not it is possible to compress air adiabatically from k to 140 kpa and 400 k. what is the entropy change during this process?

Carbon dioxide gas expands isotherm a turbine from 1 mpa, 500 k at 200 kpa. assuming the ideal gas model and neglecting the kinetic and potential energies, determine the change in entropy, heat transfer and work for each kilogram of co2.