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 process defining transient and static performance of various technical applications. This work presents an extended heat transfer model which takes the complete boiling process into account. Models from the literature for the different 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 respect to the consideration of the boiling crisis. The simulation results show good accordance with literature data.

Numerically Robust Six-Equation Two-Phase Flow Model for Stationary and Moving Systems in Modelica

“…Currently the model is further developed to feature more detailed models for friction, spatial distribution and heat transfer, e.g. (Hoppe, Gottelt, and Wischhusen 2017). It is also straightforward to extend the model to feature multicomponent media.…”

“…Sometimes these homogeneous models are extended by phenomenological models for interphase velocity difference (slip) or heat transfer and/or friction, e.g. in (Hoppe, Gottelt, and Wischhusen 2017).…”

Compact steam bottoming cycles: Model validation with plant data and evaluation of control strategies for fast load changes

“…For the two-phase flow in the boiler section, a constant heat transfer coefficient for the cold side was implemented with a value of 21 kW/m 2 K [33]. This is a common modeling assumption for two-phase flow in system level simulations, in which the boiling process is reduced to the saturated boiling regime [34].…”