Question

1. Water enters the constant 130-mm inside-diameter tubes of a boiler at 7 MPa and 65°C and leaves the tubes at 6 MPa and 450°C with a velocity of 80 m/s. Calculate the velocity of the water at the tube inlet and the inlet volume flow rate. [5-14] 2. Air enters a nozzle steadily at 50 psia, 140°F, and 150 ft/s and leaves at 14.7 psia and 900 ft/s. The heat loss from the nozzle is estimated to be 6.5 Btu/lbm of air flowing. The inlet area of the nozzle is 0.1 ft. Determine (a) the exit temperature of air and (b) the exit area of the nozzle. [5-30,*] 3. Carbon dioxide enters an adiabatic nozzle steadily at 1 MPa and 500°C with a mass flow rate of 6000 kg/h and leaves at 100 kPa and 450 m/s. The inlet area of the nozzle is 40 cm?. Determine (a) the inlet velocity and (b) the exit temperature. [5-32] 4. Steam flows steadily through a turbine at a rate of 45,000 lbm/h, entering at 1000 psia and 900°F and leaving at 5 psia as saturated vapor. If the power generated by the turbine is 4 MW, determine the rate of heat loss from the steam. [5-50,*] 5. Steam flows steadily into a turbine with a mass flow rate of 26 kg/s and a negligible velocity at 6 MPa and 600°C. The steam leaves the turbine at 0.5 MPa and 200°C with a velocity of 180 m/s. The rate of work done by the steam in the turbine is measured to be 20,350 kW. If the elevation change between the turbine inlet and exit is negligible, determine the rate of heat transfer associated with this process. [5-54]

Answer 1

9.1 Given:. (1) d = 130 mm = 0.13 m (2) Inlet Area, A, - Az Coutlet area) Co d = constant) (3) Outlet velocity, V2 = 80 m. To find : (1) Inlet velocity, Vi . (2) Inlet volume flow rate 9, Solution : at inlet of boiler, - Pi = 7 Mpa, Ti = 65°C at P, = 7 Mpa, Tsat = 285.83°C " T, 2 Tsat & at inlet of boiler , water is in sub cooled liquid from sub cooled water table, ... at P,= 7Mpa, T,= 65°c specific volume, "=0.00101672 m3 at outlet of boiler, P2 = 6 MPa , Tz = 4505 - at P2 = 6 MPa, Tsat = 275.59°C Tz > Trat : It is super heated steam at enit

from superheated steam table, at P2 = 6MPa, T2 = 450°c specific rolume, 12 = 0.0521660 miliona Applying continuity equation at inlet and outlet of tube of boiler, .: A, E A on jo 1672 = 0.0521666 80 0.0521660 0-00101672 Inlet velocity, V, = 1.56 m Inlet volume flow rate, Q, = Aivi , = The DX Vi Q. = 170.13*x 1.56 Q, = 0.02071 og OR