Refrigerant R-134a enters a steady-flow compressor at 5 °C and as a saturated vapor. a) The refrigerant follows a reversible, adiabatic process in the compressor and leaves at 1.5 MPa. The mass flow rate of the R-134a through the compressor is 0.02 kg/s. Neglecting changes in kinetic energy, calculate the power required by the compressor and the temperature of the R-134a as it leaves the compressor. b) Suppose the compressor in part (a) has friction that generates entropy as the refrigerant flows through the compressor at a rate of 1.5 (J/K) / s. What power would be required by this compressor and what would be the temperature of the refrigerant as it leaves the compressor?

I. Steam flows steadily into a turbine with a mass flow rate of 20 kg/s at 6 MPa and 600°C with a velocity of 120 m/s. The steam exits the turbine at 0.5 MPa and 200°C with a negligible velocity. Determine the power produced by the turbine and the work done per unit mass.

Air at 293 K and 100 kPa is accelerated by being sent to the nozzle after being compressed to 500 kPa in a compressor with a mechanical efficiency of 85%. The pressure at the nozzle outlet is measured as 100 kPa. Considering that the air exhibits an ideal gas behavior, the heat capacity is constant, the nozzle operates adiabatically and reversibly, and that the velocity at its inlet is negligible: a) The temperature at the compressor outlet (K) andb) Calculate the velocity (m / s) at the nozzle outlet. (Cphava = 1.005 kJ / kg.K)

Steam enters a turbine with a mass flow rate of 15 kg/s at 500°C and 8 MPa. 30% of the steam is removed in the middle of the turbine where the steam is at saturated vapor state at 300 kPa. The remainder of the steam leaves turbine exit at 10 kPa and quality of 10 percent. If the turbine is adiabatic, what is the power generated by this turbine?

Air at a rate of 50 m3/min enters an adiabatic compressor at a pressure of 100 kPa and a temperature of 24.3 C and exits at 500 kPa and 189.55 C. It then enters an insulated heat exchanger where it gets cooled by water. The air exits the heat exchanger at a temperature of 57.35 C. Water enters the heat exchanger at 20 C and exits at 50 C. Calculate the compressor power in kW, the mass for rate of the cooling water in kg/sec, and the rate of entropy generation for the compressor and the heat exchanger. Assume a mean heat capacity of water at ?? = 4.18 ??/???. You may also assume that there is no pressure drop in the heat exchanger)

A compressor performs 200 hp of shaft work to compress 0.2 kg/sec of steam from saturated vapor at 147degC to state 2 with P2, T2 = 2 MPa and 357degC. The compressor is NON-adiabatic so it is also transferring heat to the surroundings in the process. Determine the heat transfer rate from the compressor. You can assume the changes in velocity and height of the system are negligible.

One mole of carbon dioxide is to be compressed adiabatically from 1 bar and 25⁰C to 10 bar. Because of irreversibilities and poor design of the compressor, the compressor work required is found to be 25 % greater than that in a well-designed (reversible) compressor. Compute the outlet temperature of the carbon dioxide and the work that must be supplied to the compressor for both the reversible and irreversible compressors. Assume carbon dioxide is an ideal gas with the constant-pressure heat capacity (in J/mol.K) given below. (Please write assumptions) ??(?) = 22.243 + 5.977 ∗ 10^-2∗ ? − 3.499 ∗ 10^-5∗ ?2 + 7.464 ∗ 10^-9∗ ?3

Thermodynamic question

An adiabatic capillary tube is used in some refrigeration systems to drop the pressure of the refrigerant from the condenser level to the evaporator level. R-134a enters the capillary tube as a saturated liquid at 65.9 oC, and leaves at -12 oC. Determine the rate of entropy generation in the capillary tube for a mass flow rate of 0.83 kg/s.     s1 (kJ/kgK)  Format : 0.3382 x2  Format : 0.335 s2 (kJ/kgK)  Format : 0.4832 Sgen (kW/K)  Format : 0.0504