Air contained in a rigid, insulated cubic tank of edge 1 m, fitted with a paddle wheel, undergoes a stirring process between state 1: t1 = 40 °c, p1 = 400 kpa; and state 2: p2 = 800 kpa.(a). determine the temperature change in this process.
(b). determine the work done by the paddle wheel in this stirring process.
(c). determine the entropy generation in this process.
Given that the tank is insulated and rigid, heat transfer to the surrounding is zero and there is no change in volume of system(container).
p1=400kpa, T1= 40°c= 313k, p2=800kpa
volume of container = volume of cube= a³=1³=1m³
Air is acting as an ideal gas, hence, applying ideal gas equatin R= 287J/kg.k for air
a.) Process 1-2 constant volume process v1=v2
b.) According to first law of thermodynamics
where r= specific heat ratio; for air, r=1.4, R= 0.287KJ/kg.k
The negative sign means work done of system is in reverse.
c.) Entropy generation = change in system + change in surrounding
change in surrounding is zero
change in system=
v1=v2; v2/v1=1; ln(1)=0
entropy gen= 4.453*0.7175*ln(626/313) + 0 =2.215KJ/k
constructing a building's framework requires a solid foundation
try looking it up that is always