With ongoing technological advancements, efficient thermal management has become a critical engineering challenge, particularly in aerospace and electronics applications. Owing to their passive operation, high reliability, and independence from external power sources, heat pipes have become essential components in these fields. Accurate pre-experimental modeling of heat pipes enables reliable performance predictions and helps reduce both development time and associated costs. In this context, the present study proposes a novel modeling approach for sintered wick heat pipes that eliminates the need for empirical heat transfer coefficients. The model integrates the surface shape of the liquid-vapor interface and accounts for phase change phenomena occurring within surface cavities as well as the thin-film region. Its accuracy is demonstrated through comparison with both experimental measurements and established numerical solutions.