Molecular dynamics studies to understand the mechanism of heat accommodation in homogeneous condensing flow of CO₂

In the present work, we investigate the accuracy of the heat accommodation model, used in a meso-scale discrete particle BGK based condensation model for studying the homogeneous condensing flow of CO₂. It was found in those studies that the heat accommodation model played a key role in the numerical reproduction of the experiments. The major assumption made in such a heat accommodation model was the instantaneous release of heat of condensation to the gas particles in a cell. In the present work, we examine the veracity of the assumption used in the heat accommodation model, and understand the heat accommodation mechanism in general. To this end, we have used the atomistic molecular dynamics method to study the gas-cluster interactions from a fundamental standpoint. It is found that the time taken by gas-cluster interactions to establish an equilibrium from an initial state of non-equilibrium is less than the time step used in meso-scale analysis [1]. We also find that a dynamic equilibrium is established by the gas-cluster interactions in which condensation and evaporation constantly takes place to and from a cluster.