Coal–gas outbursts are governed not only by gas pressure but also by gas adsorption properties, yet how adsorption differences regulate the coupled evolution of energy release, coal fragmentation, and gas–coal two-phase flow transport remains unclear. To clarify this control mechanism, laboratory physical simulation experiments were conducted using a self-developed high-pressure outburst apparatus. CO2, N2, and He were selected to represent a strongly adsorptive gas, a weakly adsorptive gas, and a non-adsorptive reference gas, respectively. Under the same initial pressure of 0.74 MPa, CO2 exhibited sustained pressure disturbances and a peak shock-wave overpressure of 25.49 kPa at 1.5 m from the outlet. The estimated total expansion energies of He, N2, and CO2 were 13.2, 44.5, and 364.8 kJ/t, respectively, and desorption-induced expansion contributed 94.6% of the total CO2 expansion energy. The attenuation coefficients of shock-wave overpressure were 0.104, 0.114, and 0.135 for CO2, N2, and He, respectively, indicating the slowest attenuation under strongly adsorptive conditions. The dust-bag mass fractions increased from 0.2% for He and 11.6% for N2 to 22.7% for CO2. A fractal-dimension inversion between N2 and He further revealed that the final particle-size distribution was controlled by both initial fragmentation and aerodynamic sorting. A sequential mechanism of gas adsorption property–energy release mode–coal fragmentation–two-phase flow transport is proposed, providing a basis for gas-type-dependent outburst risk assessment.
