Extended Modelica Model for Heat Transfer of Two-Phase Flows in Pipes Considering Various Flow Patterns

Abstract

Boiling in vertical and horizontal pipes is a complex pro- cess defining transient and static performance of various technical applications. This work presents an extended heat transfer model which takes the complete boiling pro- cess into account. Models from the literature for the differ- ent boiling regimes are evaluated with respect to accuracy and suitability for system simulation application. A set of sub-models for each of the existing boiling phenomena is implemented and applied to the global boiling model. Special attention is paid to smooth transition between the sub-models and to numerical efficient solutions with re- spect to the consideration of the boiling crisis. The simu- lation results show good accordance with literature data.