Hydrodynamics of the NPP mixina chamber

On the example of simplified experimental and mathematical models of the fast reactor upper mixing chamber temperature and flow rate fields are investigated for stationary and dynamic operational conditions. Observation of the fluid flow structure are performed on horizontal cylindrical model 185 mm in diameter and 70 mm long. Temperature fields are measured by movable chromel-coppel microthermocouples. The investigations are performed for Re > 104 and Fr=1-10-3. It is shown that at Fr < 1 natural convection connected with temperature gradients or temperature change in time at the mixing chamber inlet causes the coolant temperature stratification in the mixing chamber. The interface of the coolant stratified areas is characterized by a sharp temperature gradient. It is concluded that the inlet and outlet conditions exert an essential effect on the coolant temperature homogeneity in the mixing chamber