The present work is one of the three pieces (upper airways, lower conductive airways and respiratory zone) of a digital twin lung model developed by the Physical and Numerical Modelling research group from the CASE department in Barcelona Supercomputing Center (BSC). In particular, the study presents the solution of fluid flow and SARS-COV-2 particle transport in the lower conductive zone of the lungs, using a geometry based on patient specific images. The specific context of the current work is framed within the European Project: CREXDATA: Critical Action Planning over Extreme-Scale Data. Its general vision is to develop a generic platform for real-time critical situation management including flexible action planning and agile decision making over streaming data of extreme scale and complexity. One of the use cases of the project is the COVID-19 pandemic crisis, studying viral evolution in patients. To that end, the first step is to develop a mechanistic multiscale model to build a toolbox aimed at having a digital twin for the treatment of patients.