AbstractThermal radiation hazards of fireballs induced by gas pipeline leakage and explosion have increasingly contributed to the occurrence of accidental disasters. To reveal the mechanism of fireball’s thermal hazards, the temperature characteristics and propagation behaviors were theoretically and experimentally studied in real scenario. This study proposed an optimization method based on optical computerized tomography (OCT) and reconstruction algorithm. The results of the new OCT algorithm were simulated by using MATLAB, which can realize the visualization of 3D temperature field of the fireball. Moreover, a full-scale gas pipeline leakage and explosion experiment was undertaken, and a series of testing data from the explosion fireball’s thermal radiation were collected by using infrared thermography technique. The simulated accuracy of 3D temperature field by the optimized OCT algorithm was verified by comparing with experimental data, it found that the relative error between the two results ranged from 10.54 to 14.67%, while the average error was less than 11%. This comparative investigation can provide a new practical application of 3D analytical method for thermal radiation damage of fireballs under gas explosion in both steady and dynamic states.