The objective of the visit is to develop a sub-model of mass transfer coefficient within the complete modelling process of ammonia emission predictions. This part of work is to improve the accuracy of mass transfer coefficient model (at least it is our intention). The activities during the visit includes: (1) to learn the complete process of ammonia emission prediction models with the help of Dr. Aarnink; (2) to identify and organize the data needed for developing sub-model of mass transfer coefficient; (3) to select possible geometry models for CFD simulations; (4) CFD modelling for studying relationship between the mass transfer coefficient and airflow rate. Until the end of visit, the investigation with different mesh resolutions has been conducted and a few geometry models for defining various boundary conditions have been studied. It is difficult to avoid the reverse flow at the outlet when symmetry boundary conditions have been imposed at the planes where we think it could be defined as symmetrical planes. During the processes, we also found that it is a challenge to run the simulation under steady conditions due to the complex geometry of the slatted floor. We need to reconsider the modelling process either for unsteady or using a wind tunnel geometry to develop the sub-model (still not sure if the situation can be treated as steady). Before we start the task, we know it is complicated, but during the process it is shown to be more complex than what we have expected.