modelConductionElementHEX_twoPhase
Extends from PartialConductionElementHEX.
Information
Implementation of the Conduction Element for the DiscritizedHex.
Concerning the heat transfer coefficient it is assumed, that the main term influencing the coefficient of heat transfer is the mass flow rate. Therefore a nominal value for the heat transfer coefficient at a nominal mass flow rate can be set. The reynolds exponents for normalization of the heat transfer coefficient for evaporation and condensation are taken from Yan, Yi-Yie, & Lin, T.-F. (1999). Condensation heat transfer and pressure drop of refrigerant R-134a in a small pipe. International Journal of Heat and Mass Transfer, 42(4) and Yan, Y.-Y., & Lin, T.-F. (1999). Evaporation Heat Transfer and Pressure Drop of Refrigerant R-134a in a Plate Heat Exchanger. Journal of Heat Transfer, 121(1). Furthermore a minimum value U_min for the coefficient of heat transfer is set to ensure heat transfer at zero mass flow.
For further documentation see the documentation of the motherclass.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.CoefficientOfHeatTransfer | U_liq_nom | 700 | Nominal coefficient of heat transfer for liquid flow |
| SI.CoefficientOfHeatTransfer | U_vap_nom | 500 | Nominal coefficient of heat transfer for vapour flow |
| SI.CoefficientOfHeatTransfer | U_tp_nom | 1000 | Nominal coefficient of heat transfer for condensation/evaporation |
| SI.MassFlowRate | m_flow_nom | 0.3 | Nominal mass flow rate for heat transfer calculation |
| Medium.MassFraction | delta_x | 0.05 | Value for interpolation width |
| Real | Re_exp_cond | 0.4 | Reynolds-Exponent for heat transfer calculation at condensation (Yan&Lin, 1999) |
| Real | Re_exp_evap | 0.5 | Reynolds-Exponent for heat transfer calculation at evaporation (Yan&Lin, 1999) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | x | Vapor quality calculated from specific enthalpies |