Chapter 7, Problem 7.51P

Air contained in a rigid, insulated tank fitted with a paddle wheel, initially at 4 bar, 40 °C, and a volume of 0.2 m, is stirred until its temperature is 353 °C. Assuming the ideal gas model with k = 1.4 for the air, determine (a) the final pressure, in bar (b) the work, in kJ (c) the amount of entropy produced, in kJ/K. Ignore kinetic and potential energy.

Thermodynamics 1

Air contained in a rigid, insulated tank fitted with a .paddle wheel, initially at 300 K, 2 bar, and a volume of 2 m2, is stirred until its temperature is 500 K. Assuming the ideal gas model for the air, and ignoring kinetic and potential energy, determine (a) the final pressure, in bar, (b) the work, in kJ, and (c) the amount of entropy produced, in kJ/K. Solve using

A rigid, insulated tank whose volume is 2 L is initially evacuated. A pinhole leak develops and air from the surroundings at 1 bar, 30°C enters the tank until the pressure in the tank becomes 1 bar. Assuming the ideal gas model with k = 1.4 for the air, determine: (a) the final temperature in the tank, in °C, the amount of air that leaks into the tank, in g, and (b) the amount of entropy produced, in J/K.

Figure shows data for a portion of the ducting in ventilation system operating at steady state. The ducts are well insulated and the pressure is very nearly 1 bar throughout. Assuming the ideal gas model for air with Cp  = 1 kJ/kg · K. and ignoring kinetic and potential energy effects, determine: (a) the temperature of the air at the exit, in °C. (b) the exit diameter, in m. (c) the rate of entropy production within the duct, in kJ/min.

Steam enters a counterflow heat exchanger operating at steady state at 0.07 MPa with a quality of 0.9 and exits at the same pressure as saturated liquid. The steam mass flow rate is 1.8 kg/min. A separate stream of air with a mass flow rate of 100 kg/min enters at 30°C and exits at 60°C. The ideal gas model with c, = 1.005 kJ/kg-Kcan be assumed for air. Kinetic and potential energy effects are negligible. Determine the temperature of the entering steam, in °C. For the overall heat exchanger as the control volume, what is the rate of heat transfer, in kW.

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A well-insulated turbine operating at steady state develops 20 MW of power for a steam flow rate of 50 kg/s. The steam enters at 5 bar with a velocity of 61 m/s and exits as saturated vapor at 0.06 bar with a velocity of 130 m/s. Neglecting potential energy effects, determine the inlet temperature, in °C. T₁= i eTextbook and Media Save for Later °℃ Attempts: 0 of 5 used Submit Answer

Twenty m³/hr of air at 600 kPa, 330 K enters a well-insulated, horizontal pipe having a diameter of 1.2 cm and exits at 120 kPa. Assume steady state and use the ideal gas model for the air. Also assume constant specific heat, cp = 1.007 kJ/kg-K for air at 330 K. Determine the mass flow rate, in kg/s, and the exit velocity, in m/s. Step 1 Your Answer Determine the mass flow rate, in kg/s. mi = Step 2 Correct Answer (Used) 0.0352 * Your answer is incorrect. kg/s Determine the exit velocity, in m/s.