Chapter 7, Problem 7.21CU

In a closed cycle gas turbine there is two stage compressor and two - stage turbine. All the components are mounted on the same shaft. The pressure and temperature of air at inlet to the first stage compressor are 1.5 bar and 20 °C respectively . The maximum cycle pressure and temperature are limited to 750 ° C and 6 bar. A perfect intercooling and reheating are used between the compressors and the turbines. A regenerator whose effectiveness is 0.7 was employed. Assuming the compressors and turbines efficiencies as 0.82 , calculate : a . Thermal efficiency of the cycle. b. Mass of working fluid for a power output of 350 kW. Assume the working fluid is air has c = 1.005 kJ / kg K , y = 1.4

Gaseous Methane actuates a Carnot power cycle in which the respective volumes at the four corners of the cycle,starting at the beginning of the isothermal expansion, are V1 = 10.10 L, V2 = 14.53 L, V3 = 226.54 L, and V4 157.73L. The cycle receives 21.1 kJ of heat. Determine a) the work and b) the mean effective pressure.

Determine the statement is true or false ASAP

True or False   An isentropic process is always reversible adiabatic.   An internally reversible compressor requires minimum power.   For a steady flow compressor, the heat loss due to irreversibility occurring in a heat transfer process across a finite temperature difference from the system boundary can be determined if the following quantities are known: the surrounding and exit temperature values and the entropy difference in working fluid between inlet and exit conditions.    The Q_loss term is same as the exergy destruction term in an exergy balance equation.   If an adiabatic compressor becomes internally reversible then we can consider it as a reversible adiabatic compressor.

Shown below is P-V diagram for a reversible cycle enclosed by 4 reversible process curves.  The curve 1-2 and the curve 3-4 are  reversible isothermal processes, and the curve 2-3 and the curve 1-4 are reversible adiabatic processes. If the cycle direction is counter clockwise, answer the question below. Select curve(s) which represent process(es) having heat interactions?____       A. curve 1-2     B. curve 2-3   C. curve 1-4   D. curve 3-4

SHOW COMPLETE AND LEGIBLE SOLUTION. FAST ANSWERS WILL BE GIVEN UPVOTE. ANSWER B ONLY.

Figure P6.90 shows a simple vapor power cycle operating at steady state with water as the working fluid. Data at key locations are given on the figure. Flow through the turbine and pump occurs isentropically. Flow through the steam generator and condenser occurs at constant pressure. Stray heat transfer and kinetic and potential energy effects are negligible. Sketch the four processes of this cycle in series on a T-s diagram. Determine the thermal efficiency.

6 A reversible power cycle R and an irreversible power cycle I te between the same two reservoirs. Each receives Qy from the hot reservoir. reversible cycle dev elops work Wy while the irreversible cycle develops work W, (a) Evaluate the rate of entropy generation o for cycle I in terms of Wy, Wg and the rature Te of the cold reservoir. (b) Demonstrate that ¢ must be positive.

Which of the following statements best describes the 2nd law of thermodynamics? The total entropy of a a reservoir must stay the same or increase. The change in internal energy for an ideal gas is given as A U=mc _▲T. V Heat energy will always be transferred from a hotter object to a colder object. Around a complete cycle, the net heat and net work additions must sum to zero. O A reversible cyclic engine can convert all the heat input it receives into useful work output.