Modeling Heat Transfer

AFT Fathom can model heat transfer simultaneously with the hydraulic calculations. Since many pipe flow design calculations neglect heat transfer, this capability is turned off by default. Hence temperature and heat loss information is not required to specify a model.

Heat transfer modeling is enabled on the Heat Transfer/Variable Fluids panel by selecting one of the two Heat Transfer With Energy Balance options. Once selected, temperature input is required at boundary junctions such as reservoirs. By default pipes are adiabatic, but different heat transfer models can be selected such as Convective Heat Transfer and Constant Heat Flux. With Convective Heat Transfer pipes can be assigned insulation and convection coefficient data to calculate heat loss or gain.

In addition, heat exchangers provide input for heat transfer with eleven heat exchanger thermal models available. Thermal linking with other heat exchangers is also provided to model cases such as heat transfer between both sides of a heat exchanger.

Finally, heat addition at pumps can also be modeled.

As heat transfer takes place during the system hydraulic solution, physical properties (such as viscosity) are dynamically updated based on resulting temperatures and a system energy balance is performed as part of the simulation.