Two Phase Flow Instabilities

The study of the dynamic behavior of a thermal system operating in forced convection flow boiling is important for the prediction and understanding of the local and global stability phenomena. Two phase flow instabilities are undesirable as they can result in mechanical vibrations and system control problems, affect normal operation, restrict operating parameters and influence system safety. Several types of instabilities induced by phase change are of relevance for the design and operation of industrial systems. The proper characterization of the instabilities and the condition for its occurrence can determine optimal and safe operation of the involved systems.

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Experimental Facility

The Two Phase Flow Instability facility is installed within the Varmeteknisk Lab, EPT, NTNU. Details about the facility can be found in the Thermal Two Phase Flow Laboratory. Main Characteristics of the facility:





System Pressure



Mass flow rate




v0 - 50K


Max. Power



Visualisation of DWO. Fluid R134a.
5mm ID .

Pressure Drop Oscillations. Fluid R134a. 5mm ID

More videos

Numerical Simulation

An in-house numerical model of the studied systems have been developed based on the least squares spectral element method.

Simulation Density Wave Oscillation.
Stable oscillation.

PhD Thesis

Il Woong Park, (2014 - 2017). Study of two-phase flow instabilities in single and parallel channels. Supervisor: Carlos A. Dorao

Leonardo Ruspini, (2013). Experimental and numerical investigation on two-phase flow instabilities. Supervisor: Carlos A. Dorao, Co-Supervisor: Maria Fernandino, Jostein Petersen

Ezequiel Manavela, (2013). Two phase flow instabilities and flow mal-distribution in parallel channels Supervisor: Maria Fernandino Co-Supervisor: Carlos A. Dorao, Jostein Petersen

Julio Pacio, (2012). Multiscale thermo-hydraulic modeling of cryogenic heat exchangers. Supervisor: Carlos A. Dorao, Co-Supervisor: Maria Fernandino, Jostein Petersen

MSc. Thesis

Luis Ugueto, (2013). Experimental Study of Density Wave Oscillations. MSc Thesis. NTNU.

Dejan Doder, (2013). Experimental analysis of the pressure characteristic cruve of a forced convection boiling flow in horizontal channel. MSc Thesis. NTNU.

Dag Stromsvag, (2011). Fundamental mechanisms of density wave oscillations and the effect of subcooling. MSc Thesis. NTNU.

Undergraduate Thesis

Mikkel Sørrum, (2013). Experimental investigation of the effect of heat flux and mass flow rate in oscillations characteristics of Density Wave Oscillations. Project Thesis. NTNU.