Development of MARS-KS Heatpipe Model and Evaluation of Heat Transfer Performance

To simulate a heat pipe with the MARS-KS (Multi-dimensional Analysis for Reactor Safety – KINS Standard) code, which is widely used for thermal-hydraulic analysis of nuclear power plant systems, the governing equations have been improved and relevant thermal-hydraulic models have been developed. For considering the effects of surface tension at the gas-liquid interface within the heat pipe, capillary pressure term was added to the governing equations. Furthermore, as the internal wick structure alters the existing flow regimes in MARS-KS, this paper describes the modification of the annular flow regime and the corresponding method for calculating the interfacial area. The enhanced model was validated against experimental data, which demonstrates the applicability of the developed model and also suggests the need of improvement of heat transfer model in condenser part. Future work will focus on implementing a liquid momentum correlation to better predict evaporator dryout and applying specialized heat transfer models, such as nucleate boiling and film condensation, to improve simulation fidelity. These developments aim to establish MARS-KS as a robust tool for heat pipe design and safety analysis.