Abstract
The explosion-suppression effects of NSSs on overpressures, flame propagation and flame tip velocities were explored under the initial pressures of 0.2 MPa, 0.3 MPa and 0.4 MPa. All experiments tested in a constant volume combustion bomb (CVCB). Explosion reaction of premixed propane–air gas in a new designed CVCB filled with nonmetallic spherical spacers (NSSs) was analyzed. The results showed that overpressures decreased under the different initial pressures. With the increase of filling density, the overpressure decreased, the time to reach explosion overpressure decreased, and the decay rate of explosion overpressure increased. It was also found that the explosion-suppression effects of NSSs on pressures. Flame front could be captured by high-speed schlieren photography. Combustion phenomena were captured including flame propagation, corrugated laminar flame, jet flame, corrugated turbulent flame as well as tulip flame under different initial pressures. Flame tip velocities also were captured. The results demonstrate that flame tip velocities decreased with the increase of filling densities. However, compared with unfilled CVCB, flame tip velocities increased after filling NSSs in CVCB under different initial pressures. NSSs suppressed the explosion overpressure in the cylinder, and promoted the flame propagation. In both cases, NSSs played a dual role. The suppression effect of NSSs was affected by both its suppression and promotion effect on the explosion. This work provides a scientific basis for the effective prevention of explosion accidents with propane–air premixtures and the development of explosion-suppression products.
Highlights
Propane is a kind of high-quality energy, and has become vital alternative energy sources
The explosion overpressure Pmax and the rate of pressure rise dP/dt are the two important explosion parameters,initial which are significant for damage of gaseous explosion
It can be explained by Birk [35] that, according to the law of momentum conservation, flame passing through the explosion suppression materials, would cause internal loss and viscosity loss (Darcy)
Summary
Propane is a kind of high-quality energy, and has become vital alternative energy sources. The dual role between effect of NSSs on flame velocity and explosion-suppression of NSSs on overpressure has not been yet investigated in detail in a confined space. With different filling densities of NSSs. Current work demonstrates the following new contributions: (1) The explosion suppression mechanism of NSSs was explained and the time history of in-cylinder pressures was analyzed in confined space. (3) Different flame propagation phenomena were all captured by high-speed Schlieren system including flame propagation, corrugated laminar flame, jet tmax to reach explosion investigated effects of NSSs on explosionflame, corrugated turbulent flame asoverpressure well as tulipand flame under differentthe initial pressures suppression. The results of thissuppressed work might a new insight for the cylinder, effectiveand promoted the flame propagation In both cases, the NSSs played a dual role. Results of this work might provide a new insight for the effective prevention of explosion accidents
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