**5. Conclusions**

In this study, natural gas explosions were conducted, employing the simulation tool of FLACS in three systems, including a single vessel, a single vessel with a pipe connected to it, and a big vessel connected to a small vessel with a pipe. The main conclusions of this study are as follows:


**Author Contributions:** All authors contributed equally to the research presented in this paper and to the preparation of the final manuscript. Conceptualization, Q.W.; Formal analysis, Y.S. and X.L.; Methodology, Z.W. and M.Z.; Supervision, J.J.; Software, F.C.; Writing—original draft, Y.S. and X.L.; Writing—review, Q.W. and C.-M.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** The study was financially supported by the National Key R &D Program of China (2016YFC0800100); the National Nature Science Foundation of China (51504190); and the Natural Science Basic Research Plan in Shaanxi Province of China (2017JM5068).

**Conflicts of Interest:** The authors declare no conflict of interest.
