Energy dissipation in a nozzle

Example 3.3 Energy dissipation in a nozzle Steam enters a nozzle at 30 psia and 300°F, and exits as a saturated vapor at 300°F. The steam enters at a velocity of 1467 ft/s, and leaves at 75 ft/s. The nozzle has an exit area of 0.5 ft2. Determine the rate of energy dissipation when the environmental temperature is T0 = 500 R. 

Assume that there are no work interactions, the potential energy effects are negligible, and the nozzle operates at steady state. 

The energy balance for a nozzle at steady-state conditions yields 

By estimating the steam flow rate, we can determine the heat loss from the nozzle  

The entropy balance contains the nozzle and its surroundings, and we have 

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