What factors do friction losses through pipes depend on?

Friction losses through pipes are influenced by multiple factors that collectively determine how smoothly a fluid can flow through the pipe.

The inside diameter of the pipe is crucial because a larger diameter decreases the velocity of the fluid for a given flow rate, which in turn reduces friction losses. Conversely, a smaller diameter restricts flow, increasing fluid velocity and consequently raising the friction losses.

Fluid velocity plays a significant role as well. When the velocity of the fluid increases, the amount of friction resulting from the fluid’s movement against the pipe surfaces also increases. This relationship is often described by the Darcy-Weisbach equation, which shows that friction loss is proportional to the square of the fluid velocity.

Lastly, the surface finish of the pipe interior affects friction losses. A rougher surface creates more turbulence and resistance as the fluid flows over it, increasing the frictional forces at play. Smoother surfaces allow for a more laminar flow, reducing the friction loss.

Since friction losses are contingent on these interconnected factors, the correct answer reflects that all the listed factors—inside diameter of the pipe, fluid velocity, and surface finish—are important in determining the friction losses through pipes.