Dust explosions are combustion of fine dust particles in a rapid reaction regime. They are of relatively common occurrence in industries which have unit operations like grinding, pneumatic conveying, drying, and fine particle collection: generally those units which handle fine particles or "dust" in an oxygen-rich environment. At present, mitigation and prevention of dust explosion accidents is largely based on operator experience and safety inspection heuristics: knowledge that often cannot be documented or put into scientifically developed safety rules. Part reason for this state of affairs is our lack of fundamental understanding on how a dust explosion progresses after ignition of the dust cloud. In this contribution, with a view towards improving our understanding of dust explosions, we propose a multi-scale modelling approach for modelling dust explosion phenomena in a standard 20 L Siwek Apparatus. The modelling approach is based on computational fluid dynamics methods treating Aluminum dust cloud as a quasi-homogeneous phase.