Thermodynamics (MECH226) Final Exam. June 25 2020 1. An ideal gas in a container of the pressure 0.1 bars is suddenly ex

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Thermodynamics Mech226 Final Exam June 25 2020 1 An Ideal Gas In A Container Of The Pressure 0 1 Bars Is Suddenly Ex 1 (31.84 KiB) Viewed 21 times

Thermodynamics (MECH226) Final Exam. June 25 2020 1. An ideal gas in a container of the pressure 0.1 bars is suddenly expanded with no heat and work communications with its surrounding. The volume becomes double at final state. Find the pressure at final state. (10) 2. Air enters a 0.5 m diameter fan at 20°C, 100 kPa, and exits at 25°C. 105 kP's with a volumetric flow rate 0.5 m/s. Find the mass flow rate and the volumetric flux at inlet. Molecular weight of air 28.97 kg/kmole. Use ideal gas relations) (10) 3. Air of 300K, Ibar and 4kg/s is compressed to 6bar by an air compressor in steady state. The compressing process is a polytropic process of n-1.2. the heat of 46.95k/kg is discharged to surroundings during the process. The C, of air is constant as Ikl/kg, and the changes in potential and kinetic energy can be ignored. Find the compressor work required for the process using the ideal gas model. (10) 4. In the cycle receiving the heat Qe from hot reservoir at Ts and discharging Q to cold reservoir at Tc. the network W... is produced. The thermodynamic efficiency of the cycle can be expressed as n=W/Q. If the cycle is reversible, the efficiency is n-1-T/T- Prove that using the thermodynamic 1 and 2 laws. Chint. Both of energy and entropy couldn't be accumulated during the thermodynamic cycle) (10) 5. The air compressor is operating at steady state. The air enters with 23, 0.12 MPa and exits at 1.5 MPa. The volumetric flow rate is 8 m/min. If the compression is done through the isothermal and internally reversible process, find the mass flow rate in kg/s and the work and heat transfer in kW Ignore the kinetic and potential energy and use the ideal gas model for air. (10)