Question

6. The working substance for a Carnot cycle is 8 lb m of air. The volume at the beginning of isothermal

compression is 9 ft 3 and the pressure is 300 psia. The ratio of expansion during the addition of heat is

2 and the temperature of the cold body is 90 o F. Find: a) Q A and Q R (BTU), b) V 3 and P 3 , c) V 4 and P 4 , d) mean effective pressure (psia).

Answer 1

a)

$$Q_A=346.4\ Btu\\Q_R= -209.1 Btu$$

b)

$$V_3=63.57\ ft^3\\p_3=25.64\ psia$$

c)

$$V_4=31.79\ ft^3\\p_4=51.28\ psia$$

d)

$$p_m=13.59\ psia$$