Facility description

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 CFD code validation (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.

Scheme of the TOPFLOW facility

The scheme shows the basic circuitries and technical systems of the facility. It includes first of all:

  • a TOPFLOW 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 circuitry, 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 slightly inclined tube or alternatively for fluid dynamic measurements with a micro-focus X-ray tube.

This equipment is completed by an electrical steam generator with a maximal connection 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 necessary 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, to limit stainless steel corrosion at the high operational temperature of up to 286 °C without dosing of additional chemicals. 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 in the environment.

At the present time the TOPFLOW facility is busy by the current projects. As of 2017 it has free capacity for new flow investigation also for external users.