The multipurpose thermalhydraulic test facility TOPFLOW was designed to investigate steady-state and transient two-phase flows at praxis-relevant operational parameters by the Institute of Fluid Dynamics on the Helmholtz-Zentrum Dresden-Rossendorf in the years 2001 and 2002. Since 2003 adiabatic and non-adiabatic test series were planned and executed in close collaboration with the Computational Fluid Dynamics (CFD) community. The measured data were used for model development and code validation in the field of thermal hydraulics (Thermofluiddynamics of two-phase flows). Beside these generic activities the facility is applied for various nuclear and procedural projects with industrial founding, e.g. Pressurized Thermal Shock experiments in cooperation with an international consortium as well as for steam condensation tests in a slightly inclined tube.
So TOPFLOW allows flow investigation as in vertical test sections as in horizontal geometries. The facility combines 3 test rigs, a steam generator module and the necessary auxiliary systems.
The scheme shows the basic circuitries and technical systems of the facility. It includes first of all:
- a pressure tank, that allows flow investigation in test sections with thin walls and glass windows for optical observation up to 5 MPa with pressure equilibrium to the tank atmosphere;
- a test section loop, included almost 8 m long vertical pipes with different nominal diameters, on which a X-ray tomograph or wire-mesh sensors were employed for flow pattern detection;
- a tomography laboratory, that currently is used for the investigation of steam condensation phenomena in a slightly inclined tube. Furthermore a vertical test section for the analysis of boiling effects is established in this laboratory.
This equipment is completed by an electrical steam generator with a maximal power of 4 MW. It supplies up to 1.4 kg/s saturated steam in a pressure range from 1 to 7 MPa and the required saturated water mass flows. Furthermore a compressed air controlling system delivers dry and filtered air in a wide norm volume flow range from 0.005 to 900 m³/h for gas injection during adiabatic air/water tests. The entire facility is filled with deionized water. So the measured data can be directly used for the validation of thermal hydraulic codes. After the tests the residual steam and water mass flows are injected into the blow-off tank, where the steam is condensed. Thereby the water in the blow-off tank is cooled by dry cooling towers, which release the energy to the environment.
At the present time the TOPFLOW facility is busy by the current projects. As of 2020 it has free capacity for new flow investigation also for external users.