Development of methane-air deflagration-driven blast wave simulator Ⅰ: geometric and structural design

Efficiently achieving plane wave loading on the test specimen is a key technical issue in the design of blast wave simulators. Based on the existing device, testing data of large-scale shock tubes, and LS-DYNA software, numerical models of blast wave propagation in simulators were established. Numerical simulations were conducted to develop a safe, economical, and reusable blast wave simulator. A quantitative method for assessing the uniformity of overpressure load on the loading area was proposed. Numerical analyses were performed to investigate the influence of the shape and length of the expansion section and the length of the conditioning section on the uniformity of overpressure load on the loading area. Key structural parameters, including the wall thickness of the expansion and conditioning sections, as well as the spacing and height of the stiffeners, were numerically optimized. Validation tests were conducted on the blast wave simulator. It is found that the established numerical model can accurately reproduce the blast wave propagation, and the prediction results show good agreement with the testing data. Taking the errors of overpressure peak value and arrival time as indicators, the quantitative evaluation of overpressure load uniformity on the loading area is achieved. Considering the balance between technical and economic factors, the developed blast wave simulator is designed with a symmetrically configured expansion section 3 m in length. The length of the conditioning section can be extended as much as the actual investment allows. Based on the numerical results, the wall thickness of both the expansion and conditioning sections is determined to be 30 mm. The height and spacing of the stiffeners are both recommended to be 150 mm. The results of validation tests confirm that the geometric and structural design meets the requirements of blast loads and structural resistance, and the developed simulator is suitable for component-level tests.