Combined numerical and experimental study of temperature pulsations in the fragment of header unit of heat exchanger of nuclear power unit clean-up and cooldown system

Experimental model of fragment of header unit of light-water nuclear power reactor clean-up and cooldown system was developed and manufactured. Experimental studies of temperature conditions were performed using the developed experimental model.Experimental distributions of temperature in characteristic zones of the header unit under study were obtained. The most thermally stressed zones of heat-exchanging surface were determined. Analysis of intensity of temperature pulsations on the heat-exchanging surface and coolant flow in different zones was performed, statistical and spectral characteristics of temperature pulsations were represented. Solutions were suggested aimed at the reduction of intensity of thermal pulsations.Calculation model of the fragment of header unit was developed and recommendations were given on the development of calculation models. Results of numerical modeling of transient temperature conditions and characteristics of temperature pulsations for different regimes of flow streamlining the model obtained using ANSYS CFX 14.0 CFD-code are presented here.Comparative analysis of experimental and calculated data was performed. It was demonstrated that calculated data are in agreement with experimental data with sufficient accuracy which gives the possibility to use the developed calculation model in the future for subsequent substantiation of heat exchanger design.