Question

Pressure loss for laminar flow through pipeline is dependent
1. Inversely on flow of velocity
2. Directly on square of pipe radius
3. Directly on length of pipe
4. Inversely on viscosity of flowing Medium

Answer 1

Correct Answer - Option 3 : Directly on length of pipe

Concept:

For pipe:

The loss of pressure head in case of laminar flow is given by:

\({h_{L}} = \frac{{32{μ \bar UL}}}{{ ρ gd^2}}\)

Parallel plate:

\({h_L} = \frac{{12\mu \bar UL}}{{ρ g{t^2}}}\)

where μ = viscosity, L = length of pipe/plate, U̅ = average velocity, d = diameter of the pipe.

Explanation:

From the above head loss expression, it is clear that 

Head loss is directly proportional to the length of the pipe.

∴ Pressure loss (ρgh_L) is also directly proportional to the length of the pipe.