Engineering Answers

A piston cylinder containing steam at 700 kPa at 250 degrees celcius undergoes a constant pressure process until the quality is 70%. Determine: a). Work done b). Heat transferred c). Change in internal energy d). Change in enthalpy NOTE: - INDICATE THE PV and TS DIAGRAM - INDICATE THE INITIAL AND FINAL STATE OF THE SUBSTANCE

Ans. (a) -101.4 kJ/kg (b) -810 kJ/kg (c) -708.5 kJ/kg (d) -810 kJ/kg

A steam engine isentropically expands 7.382 kg/sec of steam from 0.68 Mpa,

220°C, the exhaust is dry and saturated. Determine (a) the work of nonflow

process in kW and (b) the work of a steady flow process in kW. NOTE: - INDICATE THE HS and TS DIAGRAM - INDICATE THE INITIAL AND FINAL STATE OF THE SUBSTANCE

Water at 2.5 MPa and 200°C is heated at constant temperature up to a quality of 80%. Find (a) the quantity of heat received by the water, (b) the change in internal energy, and (c) the work of a nonflow process. NOTE: - INDICATE THE HS and TS DIAGRAM - INDICATE THE INITIAL AND FINAL STATE OF THE SUBSTANCE

Ans. (a) 2025.7 kJ/kg; (b) 1396.5 kJ/kg; (c) 629.17 kJ/kg

6.371 kg of water vapour are contained at 150 kPa ad 90 per cent quality in a

suitable enclosure. Calculate the heat which must be added in order to just

produce a saturated vapor. What will the pressure be at the end of the

heating process? NOTE: - INDICATE THE HS and TS DIAGRAM - INDICATE THE INITIAL AND FINAL STATE OF THE SUBSTANCE

6.86 kg of water vapour are contained at 150 kPa ad 90 per cent quality in a

suitable enclosure. Calculate the heat which must be added in order to just

produce a saturated vapor. What will the pressure be at the end of the

heating process? NOTE: - INDICATE THE HS and TS DIAGRAM - INDICATE THE INITIAL AND FINAL STATE OF THE SUBSTANCE

6.86 kg of water vapor are contained at 150 kPa ad 90 percent quality in a

suitable enclosure. Calculate the heat in kJ which must be added in order to just

produce a saturated vapor. NOTE: - INDICATE THE HS and TS DIAGRAM - INDICATE THE INITIAL AND FINAL STATE OF THE SUBSTANCE

A piston cylinder containing steam at 700 kPa at 250 degrees celcius undergoes a constant pressure process until the quality is 70%. Determine: a). Work done b). Heat transferred c). Change in internal energy d). Change in enthalpy NOTE: - INDICATE THE HS and TS DIAGRAM - INDICATE THE INITIAL AND FINAL STATE OF THE SUBSTANCE