FLUID DYNAMICS FOR PIPING DESIGN
Design factors that contribute to corrosion and erosion inside pipes are elements that increase velocity or that cause turbulent flow. Except when necessary, avoid restrictions in piping and limit bends and elbows. In some cases, a design problem causes both noise and damage. High velocity flow and sudden pressure changes not only increase damage to interior pipe surfaces or pumps, but they increase noise.
Water hammer occurs with sudden pressure changes within a pipe, such as when a valve is quickly closed. This is more than a simple noise issue, however. The sudden pressure change creates a pressure wave that can damage pipes. Poor valve choice or operation is a common culprit.
Sudden changes in pressure can also cause cavitation. Vapor forms in the pipe due to low pressure or very high velocities. Once the pressure increases above the fluid’s vapor pressure, the fluid rushes into the collapsing vapor bubble. This creates a small area of high pressure that can damage pipes and pumps.
Efficient HVAC systems are more than the best air handling units and chillers. Piping design is equally important. Fluid dynamics and material selection should work together for an efficient piping system.
Patti Dees is a chemical engineer turned writer. She spins her polymath nature to produce clear and informative pieces on technical topics.
- Cooke, Richard, (January 2015). Flow in Pipes. Land and Water Management Systems. Retrieved September 2019.