Modeling of cryogenic pulsating heat pipe using CFD techniques

This study presents new numerical procedures for simulating cryogenic pulsating heat pipes (PHPs) developed in OpenFOAM. Using a multiphase flow approach, the numerical model incorporates a combination of Lee and Min phase change models and also features conjugate heat transfer between the solid wall and fluid. Turbulence effects are modeled using the k-ε turbulence model, with wall functions implemented to capture heat transfer dynamics more accurately. The model was validated against experimental data reported in literature on a nitrogen single-loop configuration. Our code captures the overall experimental thermal performance and pressure evolution within less than 3% difference. In addition, this study demonstrates that turbulence enhances heat transfer, with turbulent diffusion contributing substantially to the overall effective thermal conductivity and thus should not be neglected. The findings also indicate that cryogenic PHP simulations must consider pressure- and temperature-dependent properties to achieve reliable predictions for different operating scenarios. This work provides a promising basis for advancing the numerical modeling of cryogenic PHPs.