Experimental Investigation of the Self-Ignition and Jet Flame of Hydrogen Jets Released under Different Conditions

Abstract

Hydrogen is a promising clean energy source and an important chemical raw material. To use hydrogen energy more safely, a high-pressure hydrogen-release platform for hydrogen self-ignition and for generating hydrogen jet flames under different experimental conditions was investigated in this study. The associated experimental analysis was based on the theory of high-pressure hydrogen tube diffusion. We found that the higher the initial release pressure, the greater the intensity of the leading shock. When the initial release pressure was high and the leading shock intensity was strong, hydrogen was more likely to ignite spontaneously inside the tube. The higher the initial release pressure, the faster the average propagation speed of the shock in the same pipe length. The time during which a stable leading shock was formed inside the tube may be related to the initial release pressure. It was found that flame combustion intensified after the passage of air through a Mach disk, and a stable flame was formed more easily at the jet boundary layer away from the orifice axis. The maximum speed of the flame tip and the flame decay speed were very high. Moreover, the flame length and the diameter of the ball flame first increased and then decreased.

Quantitative Measurement of OH* and CH* Chemiluminescence in Jet Diffusion Flames

“…Since chemiluminescence imaging can provide much useful information including the combustion state, , the location of the reaction zone, − the equivalence ratio, − and the heat release rate, − it has been widely used in research and industrial combustor control. For the flames of hydrocarbons, OH* and CH* are the most important excited-state radicals, with peak wavelengths of 308 and 431 nm, respectively.…”

Evaluation of balloon cylinder explosion incident: Understanding causes and ensuring prevention

“…This is possible because the chemical reaction that produces the flammable substance can generate enough heat to ignite it. [14,15] Figure 2 Schematic Representation of the Incident Hypothesis  Explosion: The spontaneous ignition of the hydrogen gas led to a rapid and intense combustion. The blast wave generated by the explosion shattered the cylinder and caused significant damage to the immediate surroundings.…”

Study of the Effects of Different Ambient Gases and Buoyancy on Hydrogen Jet Characteristics

“…Hydrogen possesses many characteristics that significantly differ from those of traditional fossil fuels, and the conclusions of existing studies on hydrocarbon fuel engines may not necessarily apply to hydrogen. , Hydrogen has the potential to significantly enhance the brake thermal efficiency of engines because of its high energy density, low ignition energy, and broad flammability limit. − Currently, hydrogen internal combustion engines can be classified into two types based on mixture formation: port fuel injection (PFI) and direct injection (DI). − Tang et al conducted research on the Ford P2000 hydrogen internal combustion engine and found that although the maximum power output of the engine decreased by 35 to 50% compared to gasoline engines, lean burn reduced heat losses and improved the engine’s thermal efficiency to some extent. White et al conducted an in-depth study on the performance of PFI hydrogen internal combustion engines, and the results showed that under conditions where φ (equivalence ratio) was less than or equal to 0.5, the engine reduced NOx emissions to below 100 ppm.…”

“…Hydrogen possesses many characteristics that significantly differ from those of traditional fossil fuels, and the conclusions of existing studies on hydrocarbon fuel engines may not necessarily apply to hydrogen. 9 , 10 Hydrogen has the potential to significantly enhance the brake thermal efficiency of engines because of its high energy density, low ignition energy, and broad flammability limit. 11 − 14 Currently, hydrogen internal combustion engines can be classified into two types based on mixture formation: port fuel injection (PFI) and direct injection (DI).…”