Question

feed water enters a boiler drum at 700 psia, 300°F and a specific volume of 0.0174 ft^3/lb. steam leaves the superheater of the boiler at 600 psia, 550°F and a specific volume of 0.8794 ft^3/lb. calculate: a. the flow work in BTU/lb associated with the water entering the boiler drum, b. the flow in BTU/lb associated with the steam leaving the superheater

Answer 1

$700 psia\approx4826360$ $Pa$

$600 psia\approx4136854$ $Pa$

$0.0174ft^3/lb=0.001086246503444$ $m^3/kg$

$0.8794ft^3/lb=0.05489914799588$ $m^3/kg$

Flow work of fluid as it enters (or exits) the system

$w=p\cdot v$,

where $p$ - pressure, $v$ - specific volume.

(a) $w_1=4826360\cdot0.001086246503444\approx 5.24$ $kJ/kg=2.25$ $Btu/lb$ Answer

(b) $w_1=4136854\cdot0.05489914799588\approx226$ $kJ/kg=97.2$ $Btu/lb$ Answer