Abstract The UNIQUAC model is often used, for example in engineering, to obtain activity coefficients in multicomponent systems, while the CALPHAD method is known for its capability in phase stability assessment and equilibrium calculations. In this work, we combine them by representing the UNIQUAC model according to the CALPHAD method and implementing it in the OpenCalphad software. We explain the harmonization of nomenclature, the handling of the model parameters and the equations and partial derivatives needed for the implementation. The successful implementation is demonstrated with binary and multicomponent phase equilibrium calculations and comparisons with literature data. Additionally we show that the implementation of the UNIQUAC model in the OpenCalphad software allows for the calculation of various thermodynamic properties of the systems considered. The combination provides a convenient way to assess interaction parameters and calculate thermodynamic properties of phase equilibria.

中文翻译：

---

UNIQUAC 模型在 OpenCalphad 软件中的实现

摘要 UNIQUAC 模型经常用于，例如在工程中，用于获得多组分系统中的活度系数，而 CALPHAD 方法以其在相稳定性评估和平衡计算方面的能力而闻名。在这项工作中，我们通过根据 CALPHAD 方法表示 UNIQUAC 模型并在 OpenCalphad 软件中实现它来组合它们。我们解释了命名的协调、模型参数的处理以及实现所需的方程和偏导数。通过二元和多组分相平衡计算以及与文献数据的比较，证明了成功的实施。此外，我们表明，在 OpenCalphad 软件中实施 UNIQUAC 模型允许计算所考虑系统的各种热力学特性。这种组合为评估相互作用参数和计算相平衡的热力学性质提供了一种方便的方法。