Experimental Determination of the Heat Transfer Coefficient Variation in Thermal Power Equipment Subjected to High-amplitude Oscillations

The aim of the study is to determine the effect of high-amplitude oscillations on heat transfer processes. During the operation of a transport nuclear power facility (NPF) under motion conditions, it inevitably experiences pitching. Pitching is a dynamic effect of high-amplitude oscillation on the vessel body, which is also transferred to the NPF. The purpose of the study is to determine the extent to which pitching affects thermal-hydraulic processes. The study was conducted on an experimental setup made in the form of a simple tube-in-tube heat exchanger with countercurrent motion of fluids. The heat exchanger is connected to a crank mechanism that simulates pitching. For analyzing the experimental data obtained, criterion equations and dependencies were used. The temperatures obtained during the experiment were recalculated into a heat transfer coefficient. Based on the obtained heat transfer coefficient values, conclusions have been drawn about the extent to which oscillations affect the heat transfer. The obtained study results have confirmed the theoretical conjectures that an external dynamic action may enhance the heat transfer as a consequence of thermal boundary layer destruction. The findings can be applied in designing the heat exchangers of NPFs and other devices.