Image made using the COMSOL Multiphysics® software and is provided courtesy of COMSOL.
Cooling of a steering wheel injection mold: Non-isothermal pipe flow is fully coupled to the heat transfer simulation of the mold and polyurethane part.
The Pipe Flow Module is used for simulations of fluid flow, heat and mass transfer, hydraulic transients, and acoustics in pipe and channel networks. It can be easily integrated with any of the other modules in the COMSOL® Product Suite for modeling the effects piping has on larger entities, such as cooling pipes in engine blocks or feeding and product channels connected to vessels. This allows for the conservation of computational resources in your overall modeling of processes that consist of piping networks, while still allowing you to consider a full description of your process variables within these networks. Pipe flow simulations provide the velocity, pressure, material concentrations, and temperature distributions along pipes and channels, while it can also simulate acoustic wave propagation and the water hammer effect.
The Pipe Flow Module is suitable for modeling incompressible flow in pipes and channels whose lengths are large enough that flow can be considered fully developed. With this assumption it uses edge elements, solving for the tangential cross-section averaged velocity along the edges, to avoid meshing the cross section of the pipe with a full 3D mesh. This means that the modeled variables are averaged in the pipe’s cross sections and vary only along the length of the pipe. Built-in expressions for Darcy friction factors cover the entire flow regime including laminar and turbulent flow, Newtonian and non-Newtonian fluids, different cross-sectional shapes or geometries, and a wide range of relative surface roughness values. These can be varied according to their position in the network, or directly related to the variables you are modeling.
Friction is not the only contribution to pressure loss in pipe networks. The Pipe Flow Module also considers the effects of bends, contractions, expansions, T-junctions, and valves that are computed through an extensive library of industry standard loss coefficients, while pumps are also available as flow-inducing devices. As with any physics interface in the COMSOL Product Suite, you can freely manipulate the underlying equations, add your own source or sink terms, and express physical property as functions of any model variable. COMSOL Multiphysics® also allows you to bring in data to describe a certain material property or process parameter, as well as subroutines written in MATLAB®.