Abstract:
Abstract: Renewable energy is responding to some of the key challenges facing the global society today, and the zero-carbon energy system is the fundamental way to achieve carbon neutrality, so hydrogen and ammonia have gained great attention as zero-carbon energy sources. In order to further study the combustion characteristics of ammonia-hydrogen-air premixed gas flame inside and outside the duct, the influence of ammonia doped amount (φ) on the flame morphology and the evolution of pressure inside and outside the duct under stoichiometric ratio was explored with the help of high-speed photography and pressure sensor in a 2000mm stainless steel duct with a 400mm long and 70mm wide observation window. The results show that φ significantly affects the pressure inside and outside the duct, and the time to reach the reverse flow phenomenon caused by the secondary explosion also increases. The pressure measuring point PS1 is set at 400mm away from the explosion vent in the duct to collect data, and the pressure curves in the duct under each working condition are presented as a three-peak structure, named P1, P2 and P3, the three pressure peaks are caused by the rupture of the explosion vent film, the gas venting in the duct and the gas reverse generated by the secondary explosion outside the duct, the size of P1 depends on the tensile strength of the explosion venting membrane, and its amplitude is almost independent of the φ, P 2 and P3 both increase with the increase of φ, and the P 3 increase rate is the largest, when the φ is in 50%-65%, P 2 changes from a single peak to a fluctuating pressure platform in the pressure curve diagram, and the time of the platform extends with the increase of φ. The pressure measurement point PS2 is set at the horizontal central axis of 500mm away from the explosion vent outside the duct to collect data, and the peak pressure of the secondary explosion outside the duct (P out) decreases with the increase of the φ, and the time to reach P out increases. This study provides a theoretical basis for the utilization of ammonia and hydrogen energy.
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