How to Determine if a Flow is Turbulent or Laminar

Is the current flow in the Alaska Pipeline turbulent?

(a) Is this a turbulent flow?

What would be the maximum rate if the flow were constrained to be laminar?

(b) What would be the maximum rate if the flow were constrained to be laminar?

Answer:

(a) Yes, the flow in the Alaska Pipeline is turbulent.

(b) The maximum rate if the flow were constrained to be laminar would be 3961.7 barrels per day.

The present pumping rate of crude oil through the Alaska Pipeline is 550,000 barrels per day. To determine if the flow is turbulent or laminar, we need to calculate the Reynolds number.

The Reynolds number is defined as Re = (VρD) / μ, where: V = Velocity of Fluid D = Diameter ρ = Density μ = Viscosity

The flow charge is given as Q = VA, where: Q = Flow rate A = Cross-sectional Area

Given values: Density (ρ) = 998 kg/m^3 Viscosity (μ) = 0.0038 kg/m·s Diameter (D) = 1/8" = 1.2192 m Flow rate (Q) = 550,000 barrels/day = 1.012 m^3/s

To determine if the flow is turbulent, we calculate the velocity and Reynolds number. The velocity is 0.867 m/s, and the Reynolds number is 277613, indicating turbulent flow.

To constrain the flow to be laminar, the flow rate should be adjusted to achieve a Reynolds number of 2000. This results in a maximum flow rate of 3961.7 barrels per day for laminar flow.