21. In a steady flow air enters the system at a pressure of 10 bar and 200°C with a velocity of 100 m/s and leaves at 1.5 bar and 25°C with a velocity of 50 m/s. The temperature of the surroundings is 25°C and pressure is 1 bar. Determine reversible work and actual work assuming the process to be adiabatic. Determine also the irreversibility and effectiveness of the system on the basis of one kg of air flow. Take for air : e, = 1 kJ/kg K; R = 287 J/kg K. (Ans. 200.65 kJ ; 178.75 kJ/kg, 21.90 kJ/kg ; 0.894]

21. In a steady flow air enters the system at a pressure of 10 bar and 200°C with a velocity of 100 m/s and leaves at 1.5 bar and 25°C with a velocity of 50 m/s. The temperature of the surroundings is 25°C and pressure is 1 bar. Determine reversible work and actual work assuming the process to be adiabatic. Determine also the irreversibility and effectiveness of the system on the basis of one kg of air flow. Take for air : e, = 1 kJ/kg K; R = 287 J/kg K. (Ans. 200.65 kJ ; 178.75 kJ/kg, 21.90 kJ/kg ; 0.894]

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

Steam at 50 bar and 600°C enters an adiabatic turbine and leaves as saturated vapor at 1.5 bar. The elevation of the entrance is 3 m above the exit. The velocities at the entrance and exit are 3 m/s and 0.3 m/s, respectively. a. What is the specific power produced in the turbine? Answer: 972.96 kJ/kg b. How much do potential and kinetic energies contribute to this power? Answers: Kinetic Energy Contribution = 4.6 x 104% Potential Energy Contribution = 2.98 x 105%
A rigid cylindrical tank stores 80 kg of a substance at 400 kPa and 480 K while the outside temperature is 290 K. A paddle wheel stirs the system transferring shaft work at a rate of 0.7 kW. At the same time an internal electrical resistance heater transfers electricity at the rate of 1.6 kW. A. Do an energy analysis to determine the rate of heat transfer for the tank. B. Determine the absolute value of the rate at which entropy leaves the internal system (at a uniform temperature of 480 K). Answer in kW/K C. Determine the rate of entropy increase in the system's surroundings. Answer in kW/K
A quantity of gas at 1.4 bar and 25 oC occupies a volume of 0.1 m3 in a cylinder behind a piston is compressed reversibly to a final pressure of 7 bar and a temperature of 60 oC. Sketch the process line on the p-v and T-s diagrams relative to the process line for a reversible adiabatic process and calculate the work and heat transfers in kJ and the change in entropy in kJ/K. The specific heat capacity at constant pressure, cp is 1.04 kJ/kg K and the specific gas constant, R is 0.297 kJ/kg K.
One kg of a fluid is compressed reversibly according to a law pv = 0.25 where p is in bar. The final volume is 0.25 m³/kg of the initial volume. Calculate the work done on the fluid.
In a piston cylinder system, a fluid at 0.6 bar occupying 0.07 m³ is compressed reversibly to a pressure of 10.7 bar and specific volume of 0.4 m³/ 3/kg according to the law pvn = c. The fluid then expands reversibly according to the law pv² = c to 2.6 bar. A reversible cooling at constant volume then restores the fluid back to initial state. Calculate the work for the expansion in the process in Joules. Claculate to 3 d.p. and insert
0.05 kg of a certain gas in a piston and cylinder is compressed reversibly until the pressure reaches 0.615 MPa. The initial pressure and volume were 0.1025 MPa and 0.03 m3 respectively. Determine the final temperature, the work done on the gas, the heat flow to or from the cylinder walls. i) When the process is according to law PV1.4 = C, ii) When the process is isothermal. iii) When the process takes place in a perfectly thermally insulated cylinder. (the molecular weight of a certain gas is 44 and y = 1.3).
An ideal gas, initially at 30°C and 100 kPa, undergoes the following cyclic processes in a closed system: (a) In mechanically reversible processes, it is first compressed adiabatically to 500 kPa, then cooled at a constant pressure of 500 kPa to 30°C, and finally expanded isothermally to its original state. (b) The cycle traverses exactly the same changes of state, but each step is irreversible with an efficiency of 80% compared with the corresponding mechanically reversible process. Note: The initial step can no longer be adiabatic. Calculate Q, W, ∆U, and ∆H for each step of the process and for the cycle. Take CP = (7/2)R and CV = (5/2)R.
during reversible process, 2.09 kg/s of gas rejects 322.9 kJ/s of heat isothermally at 25.5 degrees C. (for this gas, cp= 2.14 kJ/kg-K and cv= 1.62 kJ/kg-K). The initial pressure is 551.7 kPa. determine the work steady flow of the process if change in PE= 2.8 kJ/s and change in KE= 6.2 kJ/s
During a reversible polytropic process, the following data were observed: V1=4.3ft³, p1= 28.2 psia, V2= 12.8 ft³, p2= 12.6 psia. What is the work in BTU
Water contained in a closed, rigid tank, initially at 100 lbf/in2, 800oF, is cooled to a final state where the pressure is 20 lbf/in2.Determine the quality at the final state and the change in specific entropy, in Btu/lb·oR, for the process.
0.09 m² of fluid at .7 bar is compressed reversibly to a pressure of 3.5 bar according to a law PV"=C. The fluid is then heated reversibly at constant volume until the pressure is 4 bar; the specific volume is 0.5 m³/kg. A reversible expansion according to a law PV²=C restores the fluid to its initial condition. Calculate the mass of the fluid present, the value of n and the net work done on or by the system and sketch the cycle on the P-V diagram. (0.0753 kg, 1.85, 676 N-m)
2. The gain in entropy during an isothermal process of 5 lb of air at 60°F is 0.462 Btu/*R. What is the work in Btu?