# On phase change and latent heat models in metal additive manufacturing process simulation

## TL;DR

This paper extends phase change and latent heat models for metal additive manufacturing simulation, comparing their accuracy and efficiency, and introduces a novel heat integration scheme with adjustable tolerance for improved performance.

## Contribution

It proposes a new variant of the heat integration scheme that allows direct control of efficiency and accuracy, enhancing simulation performance in metal additive manufacturing.

## Key findings

- The novel heat integration scheme improves efficiency or accuracy depending on tolerance settings.
- Temperature- and enthalpy-based phase fraction models are systematically formulated.
- Comparative analysis shows the proposed scheme outperforms existing methods in key metrics.

## Abstract

This work proposes an extension of phase change and latent heat models for the simulation of metal powder bed fusion additive manufacturing processes on the macroscale and compares different models with respect to accuracy and numerical efficiency. Specifically, a systematic formulation of phase fraction variables is proposed relying either on temperature- or enthalpy-based interpolation schemes. Moreover, two well-known schemes for the numerical treatment of latent heat, namely the apparent capacity and the so-called heat integration scheme, are critically reviewed and compared with respect to numerical efficiency and overall accuracy. Eventually, a novel variant of the heat integration scheme is proposed that allows to directly control efficiency and accuracy by means of a user-defined tolerance. Depending on the chosen tolerance, it is shown that this novel approach offers increased numerical efficiency for a given level of accuracy or improved accuracy for a given level of numerical efficiency as compared to the apparent capacity and the original heat integration scheme. The investigation and comparison of all considered schemes is based on a series of numerical test cases that are representative for application scenarios in metal powder bed fusion additive manufacturing.