Chapter 6, Problem 6.121P

Q4: A centrifugal fan for ventilation plant has inlet and outlet area of 0.14 m2 and 0.15 m2 respectively. The static pressure of the fan inlet is -120 Pa and the static pressure of the fan outlet is 200 Pa. The fan consume about 1 kw when deliver 2 m3/s. Determine; a- The total pressure of the fan inlet and outlet. b- Fan total pressure and fan static pressure. c- Total and static fan efficiency.

Still Air, 101.3 kPa, 15°C The image above is of a jet engine flying to the right at speed 254 meters/sec through still air. The engine inlet area is 0.9 m². Determine the mass flow rate of the air into the engine in kg/sec. You answer should include one unit after the decimal place.

An oil pump operating at steady state delivers oil at a rate of 10 Ib/s through a 1-in.-diameter exit pipe. The oil, which can be modeled as incompressible, has a density of 100 lb/ft and experiences a pressure rise from inlet to exit of 40 Ibf/in?. There is no significant elevation difference between inlet and exit, and the inlet kinetic energy is negligible. Heat transfer between the pump and its surroundings is negligible, and there is no significant change in temperature as the oil passes through the pump. Determine the velocity of the oil at the exit of the pump, in ft/s, and the power required for the pump, in hp.

Q2: A perfect gas has a kinetic energy at inlet the compressor 8 m/s at rate of 0.35 kg/s, where the specific volume and a pressure is 0.77 m'/kg, 0.5 bar respectively and leaving with a pressure of (56) bar with 6 m/s, and specific volume 0.16 m/kg. The differential between the specific internal energy in outlet and inlet is 94 kJ/kg. The heat reject from it at rate of 3540 kJ/min. find the power done on the compressor and find the cross- sectional area of the pipe inlet and outlet. P 3:22 /

Refrigerant 134a enters an insulated diffuser as a saturated vapor at 80°F with a velocity of 1400 ft/s. The inlet area is 1.4 in?. At the exit, the pressure is 400 lb;/in? and the velocity is negligible. The diffuser operates at steady state and potential energy effects can be neglected. Determine the mass flow rate, in Ib/s, and the exit temperature, in °F.

3. A desktop computer is to be cooled by a fan whose flow rate is 0.34 m/min. Determine the mass flow rate of air, in kg/s, through the fan at an elevation of 3400 m where the air density is 0.7 kg/m³. Also, if the average velocity of air is not to exceed 110 m/min, find the diameter of the casing of the fan, in mm.

Air at 15 degree Celsius and 95 kpa enters the diffuser of a jet engine and steadily with a velocity of 250 m/s. The inlet area of the diffuser is 0.5 m^2. The air leaves the diffuser with a velocity that is very small compared with the inlet velocity. Find the mass flow of air, temperature of air leaving diffuser, power and rate of heat transfer within diffuser.

3. 12 kg of air per minute is delivered by a centrifugal air compressor. The inlet and outlet conditions of air are: V1 = 12 , P1 = 100 KPa , V1 = 0.5 - m3 and kg V2 = 904, P2 = 800 KPa , v2 = 0.14 m3 The increase in enthalpy of air passing kg KJ and heat loss to the surroundings is 700 kg KJ min through the compressor is 150 Find the work in KW.

Water vapor is a stable working device with 30 bar pressure, 320°C temperature and 100 m/s speed. enters the nozzle. The outlet pressure and temperature are 10 bar and 200°C, respectively. Mass flow rate is 2 kg/s. Neglecting heat transfer and potential energy; a) Determine the ascent velocity in m/s. b) Determine the inlet and outlet flow areas in cm2.