Objectives  The process of explosion in confined space involves not only the propagation and reflection of shock waves, but also complex afterburning effect. The afterburning effect not only enhances the shock wave intensity, but also has a great influence on the final quasi-static pressure. In order to give a prediction of the quasi-static overpressure for explosion inside confined space,

  Methods  a theoretical model for calculation of the peak valve of the quasi-static overpressure for confined explosions considering afterburning effects was proposed based on the analysis of chemical reactions and the law of conservation of energy. The results calculated by the model were then analyzed and compared with the literatures' as well as the empirical formulas' to verify the reliability and correctness of the proposed model.

  Results  The results show that, the peak value of the quasi-static overpressure calculated by theoretical model is in good agreement with the results of the experimental measurement and from the empirical formulas in the literature; the Anderson's empirical formula is inapplicable to the confined explosion condition in case of a small mass volume ratio of less than 0.5 kg/m³, and the formula given in the reference 8 may not be extrapolated to the confined explosion conditions with a large ratio of greater than 8.87 kg/m³.

  Conclusions  The study in this paper can provide a better understanding of the physical mechanism of the contribution of afterburning effect to quasi-static pressure, and provide some reference and guidance for the design of explosion-resistant structures and damage assessment.