Available for: Dymola 2015
Dependencies: Modelica Standard Library Version: 3.2.1 and Modelon Base Library 2.0
Conversion from: 1.0,.1.0.1, 1.0.2
Heat Exchanger Library 1.1 is a major release with new features and other improvements.
- Flat tube type air - gas components have been added. These are designed to model charge air coolers, stand alone or as part of a stack model.
- Flat tube type air - two phase components have been added. These are designed to model evaporators and condensers, stand alone or as part of a stack model..
- A new type of fin geometry has been added. In addition to the louvered fin types, off-set strip fins can now be modeled. Design correlations as described by Manglik & Bergles are included for pressure drop and heat transfer. The new fin type is available for all of the included heat exchanger types.
- It is now possible to discretize the flat tube internal flow orthogonal to the flow direction by the new parameter "n_orthogonal" for the air - gas and air - liquid heat exchangers. The wall is always discretized with the same number of segments as the internal flow channel. Currently the number of flow orthogonal segments is equal in all passes.
- Heat exchanger test benches are now included. These include automatic definitions of the air segmentation grid from user defined segmentation numbers and heat exchanger geometry, and spatial ploting of fluid, wall and air temperatures.
- Added exhaust as selectable medium for gas in air - gas heat exchangers, represented as an ideal gas mixture of CO2, H2O, O2 and N2.
- The fin flow resistance correlations for louvered fins by Kim & Bullard and by Chang, Hsu, et. al. have been protected against division by zero at zero mass flow rate.
- Parameters defining the flow resistance of air flow bypassing the heat exchanger in a stack was not propagated to the top level of the heat exchanger. This has been fixed.
Changes to model structure
In order to support all different heat exchanger types using common base classes, there has been some changes to the internal structure of the model with this release.
- A common template "PartialFlatTubeHX" for all flat tube type heat exchangers has been created. This defines the air side model and a replaceable internal flow channel. All geometric parameters are propagated from the geometry record to the flow channel components.
- A separate template for each of air - gas, air - liquid and air - two phase has been created. These define the flow channel model of the internal flow and parameters for the specific type of heat exchanger. The template "PartialFlatTubeInternalLiquid" replaces the previous "AirCoolantBase".
- The geometry records have been structured in a hierarchical way so that the air side geometry is defined in a class common for all types of heat exchangers.
- The discretization of the wall has been changed from a single dimension defined from flow inlet to flow outlet, to a 3D discretiztion with dimensions x, y, z. This allows the orthogonal segmentation of the internal flow within passes.
- The record "AirChannelGeo" which is used to propagate fin geometry from the main geometry record to the flow resistance and heat transfer correlations has been slightly modified so that it only includes parameters of the fins. This allows use of the same record for propagating parameters for fin on both the air and gas sides in the air - gas heat exchanger.