Chapter 6, Problem 6.69P

(15%) A small expander (a turbine with heat transfer) has 0.05 kg/s helium entering at 1000 kPa, 550 K and leaving at 250 kPa, 300 K. The power output on the shaft measures 55 kW. Find the rate of heat transfer, neglecting kinetic energies.

A multistage air compressor compresses air from 1 bar to 40 bar. The maximum temperature in Ony stage is not to exeed 400k. If the law. of compression for all the stages is putes, const and the initial temperature is 300k, find the i) Number of stages for minimum power Intermediate pressure for optimum compression as well as the power needed

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During an isentropic non-flow process with air, the pressure drops from 75psia to 30psia. The air has mass of 0.25 lbm and the initial temperature was 265°F. Find: a. The final temperature, in °F b. The heat transferred, in BTU C. The change in internal energy, in BTU d. The work done, in BTU

A steam turbine has an inlet of 2 kg/s water at 1000 kPa, 350 °C and velocity of 15 m/s. The exit is at 100 kPa, 150 °C and very low velocity (assume zero). Find the specific work (kJ/kg) and the power (kW) produced.

a 15hp motor is used to drive an air compressor. the compressor efficiency  is 75% and the air is available at 29c . find the mass of air needed if the pressure compresses to 7times initial pressure.

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During an isentropic process of 3 lb/sec of air, the temperature increases from 50 deg F to 290 deg F. Find the work for a nonflow process.

A rigid insulated tank is separated into two rooms by a stiff plate. Room A of 0.5 m3 contains air at 250 Kpa, 300 K and room B is 1 m3 has air at 200 Kpa, 1000 K. the plate is removed and the air comes to a uniform state without any heat transferred. find the final temp and pressure of the room. An ideal gas is 45 psig and 800F is heated in a closed container to 130 0F. What is the final pressure? An air bubble rises from the bottom of a well where the temperature is 25 0C, to the surface where the temperature is 27 0C. Find the percent increase in the volume of the bubble if the depth of the well is 5m. Atmospheric pressure is 101.528 kPaa. A 3000 cm3 tank initially contains compressed air at 600 kPag and 28 oC. Determine the mass of air to be withdrawn from the tank to reduce its pressure to 80 kPag while the temperature remains unchanged.