While the basic formula for calculating pipe velocity (PV = .408 * Q / D^2) is generally applicable, adjustments may be needed for fluids with significantly different properties from water, such as high viscosity oils or gases. The formula assumes a Newtonian fluid with a density and viscosity similar to water. For non-Newtonian fluids or those with very different properties, more complex calculations that account for these differences may be required.

Several factors can influence pipe velocity, including the viscosity of the fluid, the roughness of the pipe’s internal surface, the temperature of the fluid, and any bends, fittings, or obstructions in the pipe that may cause resistance to flow.

According to the continuity equation and the pipe velocity formula, if the volumetric flow rate remains constant, increasing the internal diameter of the pipe will decrease the velocity of the fluid. Conversely, decreasing the internal diameter will increase the fluid’s velocity. This is because the fluid has less space to flow through, requiring it to move faster.

Next, determine the internal diameter of the pipe. In this case, the internal diameter of the pipe is measured to be 5 in.

Gravitypipeflow calculator

Enter the volumetric flow rate of the liquid through the pipe and the internal pipe diameter into the calculator to determine the pipe velocity.

Pipe velocity

A pipe velocity describes the linear speed at which a liquid flows through a pipe. The pipe velocity depends on the volumetric flow rate of the liquid and the pipe’s internal diameter.

First, determine the volumetric flow rate through the pipe. In this example, the volumetric flow rate through the pipe is found to be 50 gpm.