Effects of concentration, temperature, ignition energy and relative humidity on the overpressure transients of fuel-air explosion in a medium-scale fuel tank

•Explosion characteristics of fuel/air mixture in a medium-scale fuel tank was experimentally studied.•Overpressure-time profile was roughly divided into 4 stages.•Typical overpressure oscillations were found in a medium-scale fuel tank.•Effects of fuel properties and initial conditions on explosion characteristics were systematically determined.•Effect of explosion vessel volumes on the overpressure parameters was revealed.