Chemical Engineering - Fluid Mechanics - Discussion

Discussion Forum : Fluid Mechanics - Section 1 (Q.No. 7)
7.
The head loss in turbulent flow in a pipe varies
as velocity
as (velocity)2
inversely as the square of diameter
inversely as the velocity
Explanation:
No answer description is available. Let's discuss.
Discussion:
11 comments Page 1 of 2.

Kirub said:   6 months ago
Here, hf​ = fD ​L​v2​/Dg.

Where hf​ is the head loss,
fD​ is the Darcy friction factor,
L is the pipe length,
D is the pipe diameter,
v is the average flow velocity,
And g is the gravitational acceleration.
(1)

Abhishek Kumar Singh said:   2 years ago
(1)

Mandar Mahajan said:   7 years ago
Darcy Weisbach equation use.

Ap = 4flV^2/2D.
(1)

A. Muthuraja said:   7 years ago

Darcy-Weisbach equation, Hf=4fl(V^2)/(2gd) shows that Hf is directly proportional to velocity^2 and f for Turbulent Flow=0.079/Re: Here Re=pvd/μ.

As f is a dimensionless number (Even V term comes in Co-efficient of friction formula), Hf 4flV^2 is correct. We can also refer Dimensional and Model Analysis.

Option A is wrong (Hf is not various with V).
Option B is Correct (Hf is various with V^2).
Option C is Wrong(Hf is not inversely as the square of diameter).
Option D is Wrong (Hf is not inversely as the velocity).
(3)

Avinash kumar said:   7 years ago
One part of erg equation, which is Burke Plummer equation for turbulent gives the relation of head loss is firstly proportional to velocity squared and inversely proportional to diameter.

Riddhi said:   7 years ago

PRASHANT said:   9 years ago

HL = (F)X(L/D)X(V2/2g).

Where,

F = Friction factor related to the roughness inside the pipe.

L = Length of the pipe.

D = Diameter of the pipe.

V = Average liquid velocity in the pipe.

2g = Two times the Universal Gravitation Constant (g=32.2 ft/sec).

Friction factor (f) = (g*D*Head loss) / 2*v^2*L.

This is general equation shows head loss is directly proportional to velocity ^2.