Institut für Neutronenphysik und Reaktortechnik (INR)

Basic Research

Work foreseen

In the KASOLA facility, basic phenomena, related to the thermal-hydraulic flow in a sudden expansion and the transitional behaviour of the flow during different flow regimes will be investigated in the frame of the Helmholtz Alliance for Liquid Metal Technologies (LIMTECH).


Thermal-hydraulic flow in a vertical backward facing step with heated walls and sodium coolant


  The flow in components with changing flow area like at the inlet and outlet of heat exchangers, tanks, and piping systems causes a change in the thermal-hydraulic behaviour. Though this topic has been dealt since many years, special issues are still open. Our related experimental and numerical work will focus on:
  • Identification of the transition regimes as a function of the flow parameters
  • Development and improvement of anisotropic heat flux and momentum models
  • Validation of DNS, LES, and RANS simulations


Transition between free, mixed and forced convection with liquid sodium

  The heat transfer regime during normal operation of a power station is usually forced convection. During start-up or shut-down conditions and during accidents, however, mixed and natural convection might occur leading to instabilities in the heat removal. Another important topic concerns the thermal load of surfaces: At any time, it should keep below predefined limits. Our related experimental and numerical work will focus on:
  • Investigation of the flow rate characteristics as a function of the heat transfer regime
  • Development of Nusselt number correlations for system codes and turbulence models for CFD codes
  • Validation of the numerical analysis tools for safety related investigations of transitional regimes in liquid metal cooled plants and facilities