simulation to obtain a self-consistent view of grain size distribution with ISM evolution. We use an isolated-galaxy simulation, which could achieve a higher spatial resolution of the ISM compared with cosmological simulations. Two improvements with respect to previous studies are expected: one is direct knowledge of full grain size distribution without relying on the two-size approximation. This leads to a better understanding of the quantities for which the grain size distribution is essential (such as extinction curves). The other is a better capability of treating the dust growth processes (accretion and coagulation), which could occur quickly. Such quick processes cannot be captured robustly by post-processing so that a simultaneous calculation of grain size distribution and hydrodynamics is essential.

This paper is organized as follows. In Section \[sec:model\], we introduce the calculation method for the grain size distribution and the scheme of the simulation. In Section \[sec:result\], we show the results and comparison with observations. In Section \[sec:discussion\], we provide additional discussions. Section \[sec:conclusion\] concludes this paper. Throughout this paper, we adopt the solar metallicity $Z_{\sun}=0.02$ for the convenience of direct comparison with our previous simulations. We also use the terms ‘small’ and ‘large’ grain radius to roughly indicate the grain 