Nanotechnology revolution seems to be one of the fastest growing industries and promising technologies in our society. Research has shown that nanoparticles exhibit certain unique qualities and properties which gave rise to its production and consumption along with its unknown health and environment effect. Nano-safety field has become one of the hot research topics that are crucial to being explored especially its imposing hazards and risk mitigation. As the study of the nanoscale particle is limited, thus, the study of the fire and explosion hazard of nanomaterials research on its potential to form explosible clouds is very crucial. Therefore, this paper is aim to investigate the explosion behaviour affected by the changes of particle size from micro to nano size particle. The study focuses on the turbulent kinetics energy flow of aluminium (Al) particles inside 20L explosion chamber. The study is developed using CFD ANSYS FLUENT simulation and validated using a set of pressure-time data. As a result, the obtained data is relevant to proof that the severity of explosion increasing with the decreasing of the Al particle size. © 2016 The Authors.