Chemical Engineering - Chemical Engineering Basics - Discussion

The correct option is "pipe length" and "mass flow rate of fluid".

The friction factor for fluid flow in a pipe depends on the pipe's roughness, fluid density and viscosity, and the flow conditions, such as the Reynolds number and the velocity of the fluid. However, it does not depend on the length of the pipe. This is because the friction factor is a property of the pipe and fluid system, and is independent of the distance over which the fluid flows.

Similarly, the friction factor is not directly dependent on the mass flow rate of the fluid. However, the mass flow rate can indirectly affect the friction factor by influencing the velocity and Reynolds number of the fluid.

@A.K.

The formula is hf = 4fLv2/2gD.

Which is made to find out the friction loss in the pipe, so the friction loss hf (frictional head) is dependent on length (how long we want to pump a fluid).

To find out friction factor value we prefer Analogies (Reynold or Colburn Analogy etc) which are fully based on dimensionless numbers(Prandtl and Stanton number) in those numbers you will never find any length factor.

On this basis I'm claiming the friction factor is independent of length.

Hope this answers your question.

Friction factor depends on the Reynolds number of the fluid and the Reynolds number depend on the velocity, density and viscosity of the fluid regardless if that fluid is laminar or turbulent, we can say that all choices affect fluid properties except option A, now you might asking whats about option B (pipe roughness), pipe roughness effect fluid velocity that is why.

The only option that doesn't have any effect on the friction factor is the length of the pipe.

Hi Guys.
Greetings.

As far as the friction factor is concerned it is true that the friction factor is independent of length, why ?

The answer is f is a dimensionless number and is a ratio of the shear stress at the wall of a conduit to the kinetic energy or velocity head of the flow, and thus you will not find any dependence of f(friction factor) on length.

Hope this answers your question.

They asked f for the pipe.

f equals 16/re.
for a pipe Reynolds no. diameter is considered.
re for a flat plate length is considered.
So for a pipe, since diameter is considered to calculate Reynolds no.
Pipe length is not required.
Friction factor is independent of pipe length.

Pressure drop due to frictional loss is (4fLv^2)/(2gD). Where f is the fanning friction factor. And that is dependent on Reynolds number which is Dv*rho/mu.

Question asked is related to frictional factor and not pressure drop die to frictional losses.

For laminar flow in pipe f=16/Re. & for turbulent flow in pipe f=0.0791*Re^-0.25. And Re depends upon fluid density, dynamic viscosity, dia of the pipe, fluid velocity. So Re does not depend upon length. That is why f is independent of length.

Friction is the resistance of slipping a fluid to fluid particles or layers and its boundary.

The factors considered are the roughness of the pipe, viscosity and density of the fluids, velocity or flow rate of the fluid and diameter of the pipe.

For laminar flow friction factor doesn't depend on length & diameter of the pipe.

But in the turbulent flow, it definitely depends on length and diameter because friction factor is a relative shear stress between fluid layers.

Pipe roughness; fluid density & viscosity and mass flow rate of fluid if these parameters u alter, frictional losses of particular will change. Isn't it? What is going to do by increasing or decreasing length.