고온 주조 공정용 Heat pipe의 상변화에 따른 냉각 성능 연구 = Cooling Performance Analysis of Heat Pipe Based on Phase Change Mechanisms in High Temperature Casting Processes

다국어 초록 (Multilingual Abstract)

This study presents a comprehensive numerical investigation of a 3 mm diameter sodium-filled heat pipe, with the aim of enhancing cooling per cooling performance in high-temperature aluminium casting processes (temperature range: 453 K ~ 873 K). The analysis used volume of fluid (VOF) based multiphase flow modeling coupled with thermo-structural coupling techniques. Liquid sodium was selected as the working fluid due to its exceptional latent heat characteristics at high temperatures. Stainless steel 316L was chosen for the heat pipe structure due to its superior thermal resistance and excellent compatibility with liquid sodium. The numerical model incorporates the Lee phase-change model, and the wick structure is physically modeled using a porous media formulation and a user-defined functions (UDF) based on the Young-Laplace equation to implement capillary pressure effects. A constant contact angle () at 5 ° on the wick interface ensures optimal liquid recovery capability and wettability. The multiphase flow analysis reveals that capillary forces acting against gravity direction form liquid films on the wick wall surface. Flow visualization confirms that liquid is continuously recovered toward the evaporator section. These results demonstrate that the optimized wick design (porosity = 0.7, mesh type N = 180) enables stable operation under extreme high-temperature thermal loading conditions. Thermo-structural coupled analysis reveals that under thermal loading conditions of 873 K, the maximum thermal deformation is 0.0461 mm occurs at the condenser outlet. This result indicates a potential risk of plastic deformation and fracture risk during prolonged operation, and suggest that design measures to mitigate stress concentration are necessary.