Turbulator - in Pipe Flow

In Pipe Flow

The heat transfer coefficient for liquids and gases flowing through pipes in heat exchangers tends to be limited due to a fluid boundary layer close to the pipe wall that is stagnant or moves at slow speed, thus acting as an insulating layer. Such heat exchangers are, for example, in domestic central heating systems. This boundary layer can be broken or reduced in thickness if turbulators are placed in the pipe, which create a turbulent flow that reduces the boundary-layer thickness and thereby increase the heat-transfer coefficient.

Examples of turbulators for pipe flow are:

• Twisted-tape turbulators, a twisted ribbon that forces the fluid to move in a helicoidal path rather than in a straight line;
• Brock turbulators, a zig-zag folded ribbon;
• Wire turbulators, typically an open structure of looped and entangled wires that extends over the entire pipe length.

Turbulators can also be put to use in certain internal combustion engines - particularly, a ramjet engine. A simple porous wire mesh placed in the diffuser of the ramjet can increase turbulence in the flow entering the combustion chamber, which aids in fuel mixing.