Mechanical Engineering Exam > Mechanical Engineering Questions > The air with enthalpy of 100kJ/kg is compress...
Start Learning for Free
The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as· the air passes through it. Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:
- a)30kW
- b)50kW
- c)70 kW
- d)90 kW
Correct answer is option 'C'. Can you explain this answer?
| FREE This question is part of | Download PDF Attempt this Test |
Most Upvoted Answer
The air with enthalpy of 100kJ/kg is compressed by an air compressor t...
All the data is give in specific which is in J/Kg but the answers are asked in Rate so you have to multiply by mass flow rate which is given in question and you will get -70 kW because work is done on the system.
Free Test
FREE
| Start Free Test |
Community Answer
The air with enthalpy of 100kJ/kg is compressed by an air compressor t...
Given data:
- Enthalpy of air before compression (h1) = 100 kJ/kg
- Enthalpy of air after compression (h2) = 200 kJ/kg
- Heat loss from the compressor (Q) = 40 kJ/kg
- Mass flow rate of air (m) = 0.5 kg/s
Approach:
To find the power required for the air compressor, we need to calculate the change in enthalpy of the air and the work done by the compressor.
Calculations:
1. Change in enthalpy (Δh):
The change in enthalpy of the air can be calculated using the formula:
Δh = h2 - h1
Δh = 200 kJ/kg - 100 kJ/kg
Δh = 100 kJ/kg
2. Work done by the compressor (W):
The work done by the compressor can be calculated using the formula:
W = m * Δh - Q
W = 0.5 kg/s * 100 kJ/kg - 40 kJ/kg
W = 50 kJ/s - 40 kJ/s
W = 10 kJ/s
3. Power required for the air compressor (P):
The power required for the air compressor can be calculated using the formula:
P = W / η
Where η is the efficiency of the compressor, which is typically given as a percentage.
Since the efficiency of the compressor is not given in the question, we cannot determine the exact power required. However, we can assume a typical efficiency of around 70% for an air compressor.
Assuming an efficiency of 70% (η = 0.7):
P = 10 kJ/s / 0.7
P = 14.29 kW
Conclusion:
The power required for an air mass flow of 0.5 kg/s, assuming an efficiency of 70%, is approximately 14.29 kW. Since this value is not provided in the answer options, the closest option is 70 kW (option C).
- Enthalpy of air before compression (h1) = 100 kJ/kg
- Enthalpy of air after compression (h2) = 200 kJ/kg
- Heat loss from the compressor (Q) = 40 kJ/kg
- Mass flow rate of air (m) = 0.5 kg/s
Approach:
To find the power required for the air compressor, we need to calculate the change in enthalpy of the air and the work done by the compressor.
Calculations:
1. Change in enthalpy (Δh):
The change in enthalpy of the air can be calculated using the formula:
Δh = h2 - h1
Δh = 200 kJ/kg - 100 kJ/kg
Δh = 100 kJ/kg
2. Work done by the compressor (W):
The work done by the compressor can be calculated using the formula:
W = m * Δh - Q
W = 0.5 kg/s * 100 kJ/kg - 40 kJ/kg
W = 50 kJ/s - 40 kJ/s
W = 10 kJ/s
3. Power required for the air compressor (P):
The power required for the air compressor can be calculated using the formula:
P = W / η
Where η is the efficiency of the compressor, which is typically given as a percentage.
Since the efficiency of the compressor is not given in the question, we cannot determine the exact power required. However, we can assume a typical efficiency of around 70% for an air compressor.
Assuming an efficiency of 70% (η = 0.7):
P = 10 kJ/s / 0.7
P = 14.29 kW
Conclusion:
The power required for an air mass flow of 0.5 kg/s, assuming an efficiency of 70%, is approximately 14.29 kW. Since this value is not provided in the answer options, the closest option is 70 kW (option C).
Attention Mechanical Engineering Students!
To make sure you are not studying endlessly, EduRev has designed Mechanical Engineering study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Mechanical Engineering.
|
Explore Courses for Mechanical Engineering exam
|
|
Similar Mechanical Engineering Doubts
Top Courses for Mechanical EngineeringView all
The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer?
Question Description
The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer?.
The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? for Mechanical Engineering 2024 is part of Mechanical Engineering preparation. The Question and answers have been prepared according to the Mechanical Engineering exam syllabus. Information about The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Mechanical Engineering 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer?.
Solutions for The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Mechanical Engineering.
Download more important topics, notes, lectures and mock test series for Mechanical Engineering Exam by signing up for free.
Here you can find the meaning of The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of
The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer?, a detailed solution for The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? has been provided alongside types of The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? theory, EduRev gives you an
ample number of questions to practice The air with enthalpy of 100kJ/kg is compressed by an air compressor to a pressure and temperature at which its enthalpy becomes 200kJ/kg. The loss of heat is 40 kJ/kg from the compressor as the air passes through it.Neglecting kinetic and potential energies, the power required for an air mass flow of 0.5kg/s is:a)30kW b)50kW c)70 kW d)90 kWCorrect answer is option 'C'. Can you explain this answer? tests, examples and also practice Mechanical Engineering tests.
|
|
Explore Courses for Mechanical Engineering exam
|
|
Suggested Free Tests
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
|
© EduRev
|
Education Revolution
|
Follow Us
|
Signup to see your scores
go up within 7 days!
Access 1000+ FREE Docs, Videos and Tests
Takes less than 10 seconds to signup