We introduce a meshfree collocation framework to model the phase change from liquid to vapor at or above the boiling point. While typical vaporization or boiling simulations focus on the vaporization from the bulk of the fluid, here we include the possibility of vaporization from the free surface, when a moving fluid comes into contact with a superheated surface. We present a continuum, one-fluid approach in which the liquid and vapor phases are modeled with the same constitutive equations, with different material properties. The novelty here is a monolithic approach without explicit modeling of the interface between the phases, neither in a sharp nor diffuse sense. Furthermore, no interface boundary conditions or source terms are needed between the liquid and vapor phases. Instead, the phase transition is modeled only using material properties varying with temperature. Towards this end, we also present an enrichment of strong form meshfree generalized finite difference methods (GFDM) to accurately capture derivatives in the presence of jumps in density, viscosity, and other physical properties. The numerical results show a good agreement with experimental results, and highlight the ability of our proposed framework to model phase changes with large jumps.

翻译：我们提出了一种无网格配点框架，用于模拟液体在沸点或高于沸点时向蒸汽的相变过程。典型的汽化或沸腾模拟通常关注流体内部的汽化现象，而本文则纳入了移动流体与过热表面接触时自由表面发生汽化的可能性。我们提出一种连续介质单流体方法，其中液相和气相采用相同的本构方程进行建模，但具有不同的材料属性。其创新之处在于采用整体式方法，无需对相之间的界面进行显式建模——无论是尖锐界面还是扩散界面。此外，液相与气相之间无需设置界面边界条件或源项。相变仅通过随温度变化的材料属性进行建模。为此，我们还提出了一种强形式无网格广义有限差分法（GFDM）的富集方法，以在密度、粘度及其他物理属性存在跳变时精确捕获导数。数值结果与实验数据吻合良好，并突显了所提框架在模拟大跳变相变问题上的能力。