7.29 A gearbox operating at steady state receives 4 hp along the input shaft and delivers 3 hp along the output shaft. The outer surface of thegearbox is at 130°F. For the gearbox,(a) determine, in Btu/s, the rate of heat transfer and(b) perform a full exergy accounting, in Btu/s, of the input power. Let To 70°F.

(a)Write the expression for exergy balance.

Answered: 7.29 A gearbox operating at steady…

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

At steady state, an electric pump motor develops power along its output shaft of 0.7 hp whiledrawing 6 amps at 100 V. The outer surface of the motor is at 150°F. Let T = 40°F.Determine: (a) the magnitude of the rate of heat transfer leaving the motor, in Btu/h.(b) the exergy flow with input power, exergy flow with output power, magnitude of exergy flowwith heat transfer leaving the motor, and exergy destruction, all in Btu/h.
At a pressure of 1 bar, a temperature of 17 °C and a mass flow of 0.3 kg/s, air enters a stable insulated compressor and exits at 3 bar, 147 °C. Determine the power required by the compressor and the exergy destruction in kW. Express the exergy disappearance as a percentage according to the power required by the compressor. Changes in kinetic and potential energy will be neglected. dead state; T0=17 °C, P0=1 bar
A domestic water heater holds 189 L of water at 60°C, 1 atm. Determine the exergy of the hot water, in kJ. To what elevation, in m, would a 1000-kg mass have to be raised from zero elevation for its exergy to equal that of the hot water? Let T0 = 298 K, p0 = 1 atm, g = 9.81 m/s2 .
EXERGY TRANSFER BY HEAT, WORK, AND MASS
Determin the exergy, in kJ, of the contents of a 1.5 m3 storage tank, if the tank is filled with: a) air as an ideal gas at 440°C and 0.70 bar b) water vapor at 440°C and 0.70 bar Ignore the effects of motion and gravity and let To = 22°C and Po=1 bar.
Water at 20 bar, 400°C enters a turbine operating at steady state and exits at 1.5 bar. Stray heat transfer and kinetic and potential energy effects are negligible. A hard-to-read data sheet indicates that the quality at the turbine exit is 98%. Can this quality value be correct? If no, explain. If yes, determine the power developed by the turbine, in kJ per kg of water flowing.
Consider 100 kg of steam initially at 20 bar and 240°C as the system. Determine the change in exergy, in kJ, for each of the following processes: a) The system is heated at constant pressure until its volume doubles b) The system explands isothermally until its volume doubles Let To = 20°C, Po = 1 bar and ignore the effects of motion and gravity.
Use the following conversions where necessary:1hp = 745.7W; ρwater = 1000 kg/m3; ρmercury = 13600 kg/m3; 1 atm = 101.325 kPa; Cp (water) = 4.18 kJ/kg °C; g = 9.81m/s2; For properties of air, use R = 0.287 kJ/kg K; Cv (air) = 0.718 kJ/kg K; Cp (air) =1.005 kJ/kg K A cogeneration power plant operating in a thermodynamic cycle at steady state. The plant provides electricity to a community at a rate of 80 MW. The energy discharged from the power plant by heat transfer is denoted on the figure by . Of this, 70 MW is provided to the community for water heating and the remainder is discarded to the environment without use. The electricity is valued at $0.08 per kWh. If the cycle thermal efficiency is 40 %, determine the i. rate energy is added by heat transfer, , in MW ii. rate energy is discarded to the environment, in MW iii. value of the electricity generated, in $ per year
At steady state, a reversible heat pump cycle discharges energy at the rate Q˙H to a hot reservoir at temperature TH, while receiving energy at the rate Q˙C from a cold reservoir at temperature TC.(a) If TH = 10°C and TC = 2°C, determine the coefficient of performance.(b) If Q˙H= 15 kW, Q˙C= 8.75 kW, and TC = 0°C, determine TH, in °C.(c) If the coefficient of performance is 5 and TH = 27°C, determine TC, in °C.
Steady-state operating data are shown in the figure for an open feedwater heater.Heat transfer from the feedwater heater to its surroundings occurs at an average outer surfacetemperature of 50°C at a rate of 100 kW. Ignore the effects of motion and gravity and let T 0 =25°C, p0 = 1 bar. Determine(a) the ratio of the incoming mass flow rates, ?̇# /?̇ $ .(b) the rate of exergy destruction, in kW.
Three return steam lines in a chemical processing plant enter a collection tank operating at steady state at 9 bar. Steam enters inlet 1 with flow rate of 2 kg/s and quality of 0.9. Steam enters inlet 2 with flow rate of 2 kg/s at 200°C. Steam enters inlet 3 with flow rate of 1.2 kg/s at 95°C. Steam exits the tank at 9 bar. The rate of heat transfer from the collection tank is 40 kW.Neglecting kinetic and potential energy effects, determine for the steam exiting the tank:(a) the mass flow rate, in kg/s.(b) the temperature, in °C.
Use the following conversions where necessary:1hp = 745.7W; ρwater = 1000 kg/m3; ρmercury = 13600 kg/m3; 1 atm = 101.325 kPa; Cp (water) = 4.18 kJ/kg °C; g = 9.81m/s2; For properties of air, use R = 0.287 kJ/kg K; Cv (air) = 0.718 kJ/kg K; Cp (air) =1.005 kJ/kg K Steam at 80 bar, 440 °C, enters a turbine operating at steady state with a volumetric flow rate of 236 m3/min. Twenty percent of the entering mass flow exits through a diameter of 0.25 m at 60 bar, 400 °C. The rest exits through a diameter of 1.5 m with a pressure of 0.7 bar and a quality of 90 %. Determine the velocity at each exit duct, in m/s.

SEE MORE QUESTIONS

Recommended textbooks for you

Elements Of Electromagnetics

Mechanical Engineering

ISBN:

9780190698614

Author:

Sadiku, Matthew N. O.

Publisher:

Oxford University Press

Mechanics of Materials (10th Edition)

Mechanical Engineering

ISBN:

9780134319650

Author:

Russell C. Hibbeler

Publisher:

PEARSON

Thermodynamics: An Engineering Approach

Mechanical Engineering

ISBN:

9781259822674

Author:

Yunus A. Cengel Dr., Michael A. Boles

Publisher:

McGraw-Hill Education

Elements Of Electromagnetics

Mechanical Engineering

ISBN:

9780190698614

Author:

Sadiku, Matthew N. O.

Publisher:

Oxford University Press

Mechanics of Materials (10th Edition)

Mechanical Engineering

ISBN:

9780134319650

Author:

Russell C. Hibbeler

Publisher:

PEARSON

Thermodynamics: An Engineering Approach

Mechanical Engineering

ISBN:

9781259822674

Author:

Yunus A. Cengel Dr., Michael A. Boles

Publisher:

McGraw-Hill Education

Control Systems Engineering

Mechanical Engineering

ISBN:

9781118170519

Author:

Norman S. Nise

Publisher:

WILEY

Mechanics of Materials (MindTap Course List)

Mechanical Engineering

ISBN:

9781337093347

Author:

Barry J. Goodno, James M. Gere

Publisher:

Cengage Learning

Engineering Mechanics: Statics

Mechanical Engineering

ISBN:

9781118807330

Author:

James L. Meriam, L. G. Kraige, J. N. Bolton

Publisher:

WILEY

SEE MORE TEXTBOOKS