Heat Exchanger
The Heat Exchanger junction type is internal to the piping system and requires two connecting pipes. This junction type allows you to model the irrecoverable loss that occurs through heat exchanger equipment. You also have the ability to specify loss factors as a function of a flow parameter.
The Heat Exchanger Properties window follows the first of the two basic Properties Window formats, displaying the connecting pipes in a fixed format. The flow direction through the junction is determined by the defined directions of the connecting pipes.
When you select Resistance Curve, the Heat Exchanger Properties Window makes additional features available. Using these new features you can input heat exchanger pressure drops that vary with flow. To enter these factors, you can specify polynomial constants, fit a curve to available data, or use interpolated x-y data.
When a variable loss is specified, AFT Fathom modifies the loss factor in the Solver to agree with the solution. You can choose any of the optional flow and pressure parameters provided, and you can specify the most convenient units.
Tube Configuration Model
The Heat Exchanger junction offers a special model for tube side pressure drop. The tube configuration model allows the user to specify tube properties and quantities, scaling and frictional characteristics, multiple passes, blocked tubes and K factors for turnarounds. The pressure drop is then calculated based on this data.
When heat transfer is modeled, the Thermal Data tab becomes active. See Heat Exchanger Heat Transfer to read about how this is modeled, and how to specify various configurations.
Special Conditions
The Special Condition for a Heat Exchanger junction functions differently than other junctions. Here you can turn off the heat transfer for the heat exchanger.
