Engineering context

Heat transfer changes a fluid’s temperature as it moves through a network, and because fluid properties depend on temperature, that change feeds back into density, viscosity, vapour pressure, pressure drop, and equipment behaviour across the connected system. Heat-transfer effects are therefore evaluated inside the solved network rather than estimated per pipe, so the temperature change and its knock-on effects on hydraulics and phase behaviour are seen together.

A practical workflow starts by defining the heat-transfer objective and operating cases (hot versus cold, ambient extremes, insulated versus bare), then building and connecting the network with the fluid selected from the database (which carries its temperature-dependent properties) and applied at the boundary, including equipment such as heat exchangers. Engineers apply the appropriate heat-transfer model — from a fixed heat transfer rate or fixed temperature change through to the detailed or buried-pipe models — and, where the detailed or buried-pipe models are used, set the insulation thickness, ambient temperature, wind speed, soil type and temperature, and related parameters those models depend on. After solving, the temperature profile is reviewed alongside pressure drop, velocity, and flow distribution; the impact on fluid properties (density, viscosity, vapour pressure) and any flashing, cavitation, or slug-flow risk is assessed; and insulation, routing, or operating alternatives are compared against the objective.

Engineering workflow

1. Define the heat-transfer objective and operating cases — state what you are evaluating (temperature change along the line, the effect on fluid properties and hydraulics, or a phase-behaviour risk) and the operating cases that expose it (hot versus cold, ambient extremes, insulated versus bare, startup versus steady running).
2. Build and connect the network — place and define the boundary conditions (the fluid is selected from the fluid database, which carries its temperature-dependent properties, and applied at the boundary), then add pipes, fittings, elevations, and equipment such as heat exchangers and connect them with pipes to establish topology.
3. Apply the appropriate heat-transfer model — choose the heat-transfer model that matches the situation and the data available, from a fixed heat transfer rate or a fixed temperature change through to the detailed or buried-pipe models where the surroundings matter.
4. Evaluate the impact of insulation, ambient temperature, and other applicable input parameters — when applying the detailed or buried-pipe heat-transfer models, set the insulation thickness, ambient temperature, wind speed, soil type and temperature, and related parameters those models depend on, since they drive the heat exchanged with the surroundings.
5. Solve and review the network — solve the connected system, then review the temperature profile alongside pressure drop, velocity, and flow distribution, since the temperature change and the hydraulic results are coupled.
6. Evaluate the impact of heat transfer on fluid properties and phase-behaviour risk — assess how the temperature change shifts fluid properties (density, viscosity, vapour pressure) and whether it raises the risk of flashing, cavitation, or slug flow.
7. Compare design and operating alternatives — compare insulation specifications, routing, or operating conditions against the objective and acceptance criteria, and document the model, parameters, and assumptions.

How FluidFlow helps

FluidFlow includes heat-transfer calculations within its steady-state pipe network solver, with model options ranging from a fixed heat transfer rate or fixed temperature change to detailed and buried-pipe models that account for insulation, ambient temperature, and the surrounding environment. It reports the temperature profile alongside pressure drop, velocity, fluid properties, and equipment behaviour across the connected system, so heat-transfer effects and their hydraulic and phase-behaviour consequences are evaluated together. It is not CFD and does not perform full transient thermal or surge analysis.

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