# Motores dc

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GUÍA No 1 DE ACTIVIDADES

TRABAJO INDEPENDIENTE T.I.
ASIGNATURA
MAQUINAS TERMICAS

DOCENTE: Maria Vilma García B.

ESTUDIANTE_______________________________ CARNET_________IDENTIFICACIÓN DE LA ACTIVIDAD:

COMPETENCIA: Aplicar los conceptos de entropía con el fin de mejorar las eficiencias
OBJETIVO: Aprender, comprender y aplicar los conceptos básicos relacionados con entropíaaplicándolo como
RECURSOS: Notas de clase, textos descritos en bibliografía, Biblioteca, Internet.

• PROBLEMAS DE APLICACIÓN - SITUACIONES EN CONTEXTO

1. Combustion gases enter an adiabatic gasturbine at 1540°F and 120 psia and leave at 60 psia with a low velocity. Treating the combustion gases as air and assuming an isentropic efficiency of 82 percent, determine the work output of theturbine. Answer: 71.7 Btu/lbm (7.132)
2. Argon gas enters an adiabatic turbine at 800°C and 1.5 MPa at a rate of 80 kg/min and exhausts at 200 kPa. If the power output of the turbine is 370 kW,determine the isentropic efficiency of the turbine. (7.133)
3. Air is compressed by an adiabatic compressor from 100 kPa and 12°C to a pressure of 800 kPa at a steady rate of 0.2 kg/s. If the isentropicefficiency of the compressor is 80 percent, determine (a) the exit temperature of air and (b) the required power input to the compressor.
4. Air is compressed by an adiabatic compressor from 95 kPa and27°C to 600 kPa and 277°C. Assuming variable specific heats and neglecting the changes in kinetic and potential energies, determine (a) the isentropic efficiency of the compressor and (b) the exittemperatur of air if the process were reversible. Answers: (a) 81.9 percent, (b) 505.5 K
5. Air at 200 kPa and 950 K enters an adiabatic nozzle at low velocity and is discharged at a pressure of 80 kPa.If the isentropic efficiency of the nozzle is 92 percent, determine (a) the maximum possible exit velocity, (b) the exit temperature, and (c) the actual exit velocity of the air. Assume constant...