Mechanical Engineering - Heat Transfer, Refrigeration and Air Conditioning - Discussion


The most commonly used method for the design of duct size is the

[A]. velocity reduction method
[B]. equal friction method
[C]. static regain method
[D]. dual or double method

Answer: Option C


No answer description available for this question.

Syed Khaja Mohinuddin said: (Feb 11, 2015)  
Its a rarely used method and only for circular duct. In gulf equal friction method is used.

Ritzie Argota said: (Mar 15, 2016)  
Static regain has complicated method of calculating the size of duct. The equal friction should be considered as commonly used method in duct sizing.

Wael said: (Oct 4, 2016)  
The equal friction method is the most commonly used.

Charit said: (Oct 25, 2016)  
Please, clarify me. I think it's option B. Equal friction method.

Bholia said: (Apr 23, 2017)  
Why not A?

Anil said: (Sep 27, 2017)  
Option A is correct.

Durgesh Kumar Dubey said: (Nov 3, 2017)  
Equal friction method is correct answer.

Wina said: (Nov 13, 2017)  
Here the total frictional drop and fitting pressure drop is calculated for the ducts, and the line with the biggest pressure drop is taken. This method is the most accurate but take lots of time for calculation.

Shivam Roy said: (Dec 5, 2017)  
Equal friction method is the correct answer.

Ahmed said: (Feb 6, 2018)  
Equal friction method is more efficient.

Akshay Nandwanshi said: (Oct 11, 2018)  
Yes, Equal friction method is the right answer.

Ash said: (Oct 22, 2018)  
It's equal friction method.

Dhaval Chaudhary said: (Nov 13, 2018)  
The Answer A is correct by R.K Jain.

Anilreddy said: (Jan 19, 2019)  
Given answer option C is right.


Naresh said: (Feb 8, 2019)  
B is the Correct answer.

Bmsce said: (Feb 22, 2019)  
Equal friction method is the correct answer.

Static regain method is not suitable for long ducts.

Tony Stark said: (Jun 21, 2019)  
For ducts total pressure (To) = PS + PV.
Where, ps= static pressure.
Pv= velocity pressure, so answer C is right.

Shrivardhan said: (Dec 11, 2019)  
Equal friction method is right answer.

Reference - lesson 38 of nptel R & AC subject.

Nithin John Simon said: (Mar 4, 2020)  
Velocity, equal friction, and static regain are all commonly used methods, but the most simple one among them is velocity method only.

Vinay Bel said: (Sep 11, 2020)  
Equal friction method should be right one.

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