Explosion Vessel Research Articles

Three-dimensional dynamics of unstable lean premixed hydrogen-air flames: Intrinsic instabilities and morphological characteristics

The 3D swinging laser sheet technique was employed to study the development and morphological characteristics of premixed hydrogen-air unstable flames in a spherical explosion vessel. Pressure dependencies for laminar flame propagation were sought to exploit the role of the Darrieus-Landau (DL) and Thermal-diffusive (TD) instabilities in the unstable self-accelerating flame regime. A sufficiently low Markstein number, as a consequence of the increased pressure, leads to more cracking and smaller cells over the flame surface. The degree of wrinkling on the flame surface is proportional to the increase in flame burning velocity, a relationship that holds true for low pressures but is not applicable under high pressures. External turbulence can significantly alter the extent of flame surface wrinkling even at low root mean square velocities, producing a more wrinkled flame surface compared to intrinsic cellularity, and distinctly affecting flame dynamics. The increased wrinkling and flame speed due to external turbulence can be attributed to the synergistic effects between thermo-diffusive instabilities and turbulence, resulting in higher fuel consumption rates per flame surface area and the formation of finger-like structures that enhance flame displacement speed in curved segments. The parameters, ϵ, deviation of the Lewis number from a critical value, and ω2, obtained through classical linear stability analysis, display a clear linear relationship with the ratio of the wrinkled surface area observed in planar flames. This study enhances the understanding of hydrogen flame instabilities, which is crucial for preventing explosions in hydrogen storage and utilization, and provides valuable insights into flame dynamics, supporting the design of safer and more efficient hydrogen-fueled engines and turbines.

Investigating the explosive characteristics of hydrogen/ n-butane blended fuel: Experimental and kinetic insights

Investigating the explosive characteristics of H2/n-C4H10 mixtures is crucial for the safe utilization of this blended fuel. Our study focused on varying equivalent ratios and hydrogen blending ratios within a closed 20-L spherical explosion vessel. Additionally, the microscopic kinetics of the reactions were analyzed through chemical reaction simulation. Our findings indicate that the most violent explosion occurred at an equivalent ratio of 1.2. Increasing hydrogen content intensified combustion reactions, reducing flame thickness and inducing cellular structures along the flame front. This escalation also increased explosion pressure, flame temperature, and flame propagation speed, elevating explosion risk. Moreover, the equilibrium molar fraction of O2 and CO2 decreased while that of H2O increased with higher hydrogen blending ratios. Correspondingly, the heat release rate and generation rates of H•, O•, and OH• radicals increased. Notably, the peak time of C2H4 and CH4 consumption rates preceded. Additionally, R5: O2 + H• = O• + OH• and R978: C4H10 + H• = SC4H9 + H2 represented crucial promoting and inhibiting steps, respectively. These insights deepen our understanding of the explosion mechanism of H2/n-C4H10 mixtures, providing a theoretical basis for designing safer protective measures and evaluating explosion risks in industrial production.

Impacts of hydrogen fraction and equivalence ratio on the explosion characteristics of ethanol/hydrogen mixtures

With the anticipated widespread integration of biofuels and hydrogen fuels within the future energy landscape, the potential explosion hazards after their release within confined spaces under the atmospheric are deserving of heightened attention. The present work takes the mixtures of ethanol and hydrogen as the objects and experimentally studies the impacts of hydrogen fraction and equivalence ratio on the explosion characteristics in a constant-volume explosion vessel at 0.10 MPa and 400 K. The data reveals that an increase in the hydrogen fraction leads to a rise in the maximum explosion pressure during lean explosions but causes a decrease during rich explosions. Nonetheless, the duration of the explosion decreases with the increase of hydrogen fraction in all the explosions. In consideration of explosion pressure, the maximum pressure rise is found to be exponential in relation to the maximum explosion pressure. However, the confidence level diminishes significantly with an increase in the hydrogen fraction. Conversely, the maximum rate of pressure rise during an explosion appears to be a function of the duration of the explosion, suggesting that the reaction rate plays a more pivotal role in determining the hazardous level. Meanwhile, the duration of fast combustion steadily occupies approximately 83 % of the explosion duration. Furthermore, the deflagration index is no more than 30 MPa*m/s, namely, ethanol/hydrogen mixture is a promising fuel with mild hazardous potential.

Study on the influencing factors of gas-liquid two-phase explosions of hybrid methane/isoprene on the basis of bush fires

To evaluate the explosion hazard of hybrid isoprene/biogas in a primary forest environment, a 20 L spherical explosion vessel combining with a colorimetric thermometry was used to study the explosion parameters, flame structures and temperature distributions of hybrid isoprene/methane at different methane content and initial temperatures. Furthermore, the relationships between the explosion gas products and explosibility of hybrid isoprene/methane were analyzed. Experimental results showed that when the mass concentration of isoprene was 272.4 g m−3, the explosion pressure, the pressure rising rate, and the average combustion temperature reached their peak values of 0.89 MPa, 63.9 MPa s−1 and 2216 K, respectively. When the mass concentration was fixed at 272.4 g m−3, the explosibility of hybrid isoprene/methane initially enhanced and then decreased with the increasing methane volume fraction, and got the maximum values at 5 vol% methane. It was worth noting that the explosibility of hybrid methane/isoprene weakened continuously as the initial temperature increased, and it exhibited a stronger explosion power at a lower temperature. The research results would be helpful for understanding the deflagration processes and mechanisms of bush fires under various conditions, providing scientific basis for the formulation of its prevention and control measures.

Hazard evaluation of ignition sensitivity and explosion severity for aluminum and aluminum powder-petroleum ether mixtures

The safety implications of aluminum powder and petroleum ether have garnered significant attention as two typical materials in the production process of energetic materials. To investigate the effect of the common solvent petroleum ether on the ignition and explosion characteristics of aluminum powder, ignition energy, flame propagation characteristics, and explosion pressure of three aluminum powder sizes and their mixtures with petroleum ether through a Hartmann tube test device and a 20 L spherical explosion vessel test system. Findings show that the ignition energy of aluminum powder initially decreases and then increases with the increase of petroleum ether content. At the petroleum ether concentration of 5.5 % and 11 %, the minimum ignition energies of the mixed systems of Al-Flake, Al-T4, and Al-T2 are 1–20 mJ, 5–30 mJ, 450–485 mJ, and 1–20 mJ, 5–25 mJ, 440–480 mJ, respectively. Lower than the minimum ignition energy of the original sample (1–30 mJ, 10–40 mJ, 470–510 mJ), indicating that the aluminum powder dust containing low concentration solvent (5.5%, 11 %) is more sensitive to an electric spark. The ignition energy of the mixed system is rather increased when the content of petroleum ether is further increased to 16.5 %. On the contrary, the probability of ignition and the electric spark sensitivity are decreased. With the addition of petroleum ether to Al-Flake and Al-T4, the flame propagation speed slightly decreases and the phase duration lengthens. The flame propagation characteristics and combustion state of Al-T2 with large particles remained largely unchanged after the addition of petroleum ether. During the 20 L spherical explosion vessel test, the maximum explosion pressure and explosion index of the mixed samples initially increase and then decrease with the increase in petroleum ether concentration. A small quantity of petroleum ether intensifies the reaction intensity of aluminum dust. At an aluminum powder dust concentration of 250 g m-3, the explosion pressure and explosion index of Al-Flake and Al-T4 peak at a petroleum ether content of 5.5 %, while Al-T2 reaches its peak at 11 %.

Effect of Temperatures on Flame Propagation of Diethyl Ether Spray Explosion

ABSTRACT The study aims to identify the flame propagation in the diethyl ether (DEE) spray explosion through mathematical analysis by processing the gray-level histogram of the flame images. Different ambient and material temperatures’ effect on flame propagation and structure was investigated using a high-speed camera in a 20-L explosion vessel. The results showed that the overall duration could be divided into combustion and deflagration processes. With the ambient temperature increased, the combustion duration showed a trend of first decreasing, then increasing, and then decreasing again. The combustion zone first increased and then decreased. The explosion duration showed an overall decreasing trend. The explosion duration was longer than the combustion duration, ranging from 152.75 to 307 ms. The overall combustion and explosion duration trend was consistent with the explosion duration. When the ambient temperature was 308.15 K, the combustion duration reached its minimum value of 13.25 ms, and the equivalent radius of the combustion zone reached its maximum value of 52.89 mm. With the increase in material temperature, both the combustion and explosion durations showed a trend of first decreasing and then increasing, with combustion durations ranging from 12.42 to 16.25 ms and explosion durations ranging from 106 to 117.5 ms, respectively. When the material temperature was 308.15 K, the combustion zone expansion rate reached its maximum value of 10.20 m/s, and the explosion zone expansion rate reached its maximum value of 13.36 m/s. The effect of ambient temperature on the development of combustion zone is greater than that of material temperature, which is mainly reflected in the obvious change of equivalent radius.

Explosion characteristics of lithium-ion batteries vent gases containing dimethyl carbonate at elevated temperatures

Dimethyl carbonate (DMC) is a common component of lithium-ion batteries (LIBs) electrolyte, which is vented into the environment along with LIBs thermal runaway vent gases (BVG). This study used different ratios of DMC/BVG mixtures to simulate the combustible components vented from LIBs thermal runaway process. The explosion characteristic parameters of the DMC/BVG mixtures, such as the peak overpressure (Pex), the peak rate of pressure rise ((dp/dt)ex), lower flammability limits (LFL) and limiting oxygen concentrations (LOC), were investigated in an 8-L stainless steel cylindrical explosion vessel. The results indicated that as the percentage of DMC increased, maximum Pex, maximum (dp/dt)ex and LOC of the mixtures increased, while LFL showed a decrease trend. In addition, LFL decreased approximately linearly as increasing the initial temperature. The Britton correlation method can estimate LFL at varying initial temperatures. The research results are helpful to better understand the risk of the mixtures vent from LIBs and provide a reference for the explosion-proof design of LIBs’ transport containers and LIB energy storage stations.

Research on explosion venting characteristics of CH4/H2/Air mixture in square explosion vessels

Hydrogenation of methane (CH4) is an important means of achieving energy savings and large-scale hydrogen (H2) transportation. Explosion venting is considered to be an effective method to reduce the risk of gas explosions. To investigate the parameters of the explosion characteristics of CH4/H2/Air premixed fuel under venting conditions, the explosion characteristics and the dynamic propagation law of venting flame in CH4/Air mixtures with 5% concentration were studied in 20 L and 40 L square explosion venting vessels. The development process of flames inside vessels, the evolution characteristics of explosive venting flames, and the changes in explosion pressure were tested using a high-speed camera and pressure sensors. The maximum explosion pressure, the maximum explosion pressure rise rate, and the maximum flame velocity increased first and then decreased with the addition of H2. However, the maximum flame length increased continuously with the increase of H2. With the increase of hydrogenation, the maximum flame area showed an exponential increase. At equivalence ratio less than 1, the effect of hydrogenation on the flame area was much attenuated than that at equivalence ratio was greater than 1.

The overpressure and temperature characteristics of high volatile liquid fuel explosions in extreme environments: Effects of low initial ambient temperatures and pressures

The explosion characteristics of petroleum ether-epoxy propane-air mixtures were studied in a 20 L spherical explosion vessel at low initial ambient temperatures (243–293 K) and absolute pressures (61.3–101.3 kPa). The effects of variations in single and coupled ambient conditions on the explosion pressure and temperature of high volatile liquid fuels were obtained through a series of experiments. The results showed that the peak explosion pressure and temperature were invertedly correlated with ambient temperature, and decreased with decreasing ambient pressure. Compared to ambient pressure, ambient temperature had a greater influence on explosion temperature, while ambient pressure had a greater influence on explosion pressure than ambient temperature. The variations of peak explosion pressure and temperature were more significant under the coupled effects of low temperature and pressure. Based on these results, the effects of low ambient temperature and pressure on the explosion characteristics of high volatile liquid fuels were systematically investigated, and a prediction model for peak explosion pressure and temperature was proposed.

Experimental investigation and numerical analysis on the confined deflagration behavior of methane-air mixtures within the suppression of typical haloalkanes

To investigate the mechanisms of haloalkanes in promoting and inhibiting explosions in methane-air mixtures, the halon alternatives of CHF3, C3HF7, and C3H2F6 were selected as inhibitors. Experimental research was conducted in a 20-liter spherical explosion vessel to examine the promotional and inhibitory effects of these haloalkanes on methane-air mixtures. The adiabatic flame temperature, heat release rate, and concentrations of the key radicals were calculated. The results showed that C3H2F6, C3HF7, and CHF3 all exhibited a dual effect, initially promoting and subsequently inhibiting explosions in fuel-lean methane-air mixtures. The critical explosion suppression volume fractions of C3HF7 and CHF3 were 1.5 times and 2.25 times that of C3H2F6, respectively, for the suppression of methane explosion at Φ = 1.2. Furthermore, C3HF7 demonstrated a dual impact on the explosion of stoichiometric methane-air mixtures. From the perspective of reaction kinetics, for fuel-lean methane-air mixture (Φ = 0.8), a small volume of halogenated hydrocarbons led to an increase in the adiabatic flame temperature due to the heat release from critical fluorine-containing elementary reactions, thereby promoting the explosion. Under fuel-lean conditions, the introduction of a small volume of halogenated hydrocarbons led to an increase in the adiabatic flame temperature due to the heat release from critical fluorine-containing elementary reactions, thereby promoting the explosion. Simultaneously, these fluorine-containing reactions scavenged the key free radicals of H, O, and OH inhibiting the explosion process. These two effects competed with each other, ultimately determining the direction of the explosion process.

Influence of polyurea on dynamic response behaviors of cylindrical composite shells under internal explosion load

The dynamic responses of open-ended cylindrical shells with different polyurea layers under explosion load are studied in the current paper. The influences of polyurea thickness and position on the response characteristics of the composite shell are analyzed in detailed. The results indicate that the polyurea layer has significant influence the failure mode and energy absorption of the composite shell. Both polyurea in the interlayer and on the outer layer will decrease the bending moments of the composite shells of equal mass in the initial deformation process, which is easier to make the increase of the deformation heights of metal liner of composite shells with polyurea layers. The polyurea in the interlayer will weaken the constraint of metal liner, delay the fracture of fiber and restrain the bulking phenomenon of metal liner. With increase of polyurea thickness, the bulking phenomenon becomes less obvious and the deformation height of liner decreases non-monotonously. On the contrary, the outer layer polyurea will cause the bulking phenomenon of metal liner more obviously with increase of the polyurea thickness.But the outerlayer polyurea will restrict the deformation of the inner materials and limit the scattering of fiber fragment, improving the safety distance of the explosion vessel. In the whole process of anti-explosion, both polyurea in interlayer and outer layer absorb less than 10% of total energy, but they can significantly change the energy absorption of metal liner and fiber composite.

Study on the explosion characteristics and flame propagation of hydrogen-methane-air mixtures in a closed vessel

In this study, the examination of the explosion pressure and flame propagation characteristics were investigated for premixed CH4–H2-air mixtures, with varying equivalence ratios (φ = 0.8–1.5) and methane volume ratios (R = 0–100%). This investigation was conducted employing a 20 L explosion vessel and a high-speed ripple shadow meter, while maintaining ambient temperature and pressure. The most critical primitive reactions effecting the formation and consumption of OH* were obtained by normalisation through rate analysis. The result found that as the R increased at the same φ, the premixed system exhibited a gradually decreased in the Pmax, (dP/dt)max, and KG. The increase in the R caused the flame structure to stabilise, extending the flame front distance and the time to reach the wall. The reaction process was divided into three phases based on the R: 0 < R<40% (dominated by hydrogen combustion), 40% < R<80% (dominated by methane and hydrogen co-combustion), and 80% < R<100% (dominated by methane combustion). The analysis of OH* production rate showed that R84 and R38 were the most dominant reactions promoting the OH* production and consumption, respectively. As R was increased, both the production and consumption rates of OH* decreased resulting in a weakening of the explosive reaction's intensity.

Suppressive effects of alkali metal salt modified dry water material on methane-air explosion

As an abundant and efficient energy source, methane has a wide range of applications and development prospects, but it has a high explosion risk. In order to prevent the occurrence of methane explosion accidents, a new type of dry water material (DW) was used to suppress explosion, and alkali metal salts were added to improve the suppression effect. In this work, the optimal DW with complete monomer and uniform structure can be prepared by stirring nano-silica and deionized water at a mass ratio of 1:10 at a speed of 10000 rpm for 60S. The suppression effect of dry water was analyzed by performing methane-air explosion experiments with different powder concentrations in 20L explosion vessel. The results show that under the action of alkali metal modified DW, the Pmax and the deflagration index KG of methane-air explosion were significantly reduced. The improvement effect of potassium salt-dry water (PS-DW) ranked as KCl＞ K2CO3＞ K2C2O4·H2O＞CH3COOK, and the improvement effect of sodium salt-dry water (SS-DW) ranked as Na2CO3>NaCl > NaHCO3>NaH2PO4. Moreover, the explosion suppression mechanism of alkali metal salt modified DW was analyzed from four aspects: heat insulation, cooling, dilution and interruption of chain reaction. The study confirmed the important application potential of DW in preventing natural gas leakage explosion and coal mine gas explosion accidents. The optimal selection of modified additives in alkali metal salts holds significant importance for the widespread application of novel dry water composite materials.

Self-Acceleration and global pulsation of unstable laminar Hydrogen-Air flames

The self-acceleration and global pulsation of spherically expanding laminar hydrogen-air flames were studied in a spherical explosion vessel, over a wide range of equivalence ratios (0.4–2.0), initial temperatures (300–400 K), and initial pressures (0.1–0.7 MPa). Comprehensive quantitative data on the self-acceleration propagation of unstable laminar hydrogen-air flames were obtained. The results show that the self-similarity appears after the onset of instability, and the previous assertion of acceleration exponent α = 1.5 is not valid for hydrogen-air flames. The derived values of α for such flames vary from 1.125 and 1.39 in the present work. For the self-accelerating flame, the temporal evolution of the flame radius is described by ru=Atα, and temporal flame propagation speed is described by Sn=Aαtα-1. A modified theoretical expression of the constant A is proposed and validated against the present experimentally derived results. The acceleration phase after flame instability presents a global pulsating acceleration pattern. The frequency of global pulsation rises as the pressure or temperature of the flame increases. A pulsing flame speed equation can be used to reliably estimate flame speed after the onset of cellular instability. Self-acceleration observed in small laboratory explosions can serve as a predictive indicator for flame behaviour on a larger atmospheric scale.

Chemical inhibition of hydrogen-air explosions: Literature review, simulations and experiments

This paper summarises the first results from the joint industry project (JIP) ‘Risk-reduction for hydrogen installations by partial suppression of explosions’ (HyRISE). The main objective of the project is to develop fundamental knowledge that can support the development of practical solutions for mitigating hydrogen explosions in congested and confined environments by means of active systems for chemical inhibition. The aim is not to extinguish the incipient flame, but rather to lower the reactivity of the fuel-air mixture prior to ignition, and thereby reduce the consequences of an accidental explosion to a tolerable level. The paper consists of three parts: a review of previous work on chemical inhibition of premixed hydrogen-air flames, simulations with the chemical kinetics software Cantera, and experiments conducted in a 20-litre explosion vessel. The results demonstrate that chemical inhibition can be effective for hydrogen-air mixtures. However, it remains to develop efficient inhibitors and practical systems that can be implemented in industrial facilities, with satisfactory performance over a wide range of hydrogen concentrations.

A sneak peek into the phenomenology of fuel mist explosions: The key role of vapor fractions

The modern world depends greatly on hydrocarbons, which are ubiquitous, indispensable fuels used in nearly every existing industry. Although important, their use may trigger dangerous incidents, whether in their production, handling, storage, or transporting phase, especially when aerosolized. In light of proposing a standard procedure to assess the flammability and explosivity of fuel mists, a new test method was established based on the EN 14034 standards series. For the previous purposes, a gravity-fed mist generation system was designed and employed in a modified 20 L explosion vessel. This test method allowed the determination of the ignition sensitivity of several fuels. In addition, their explosion severity was represented by the explosion overpressure Pex, and the rate of pressure rise dP/dtex, two thermo-kinetic parameters determined with a specifically developed control system and custom software. Nonetheless, a noticeable difference in the ignition sensitivity and the explosion severity was perceived when changing suppliers or petroleum cuts of some fuels. Moreover, sensitivity studies showed that both the droplet size distribution and the temperature of the droplets play a significant role in fuel mist explosion. These parameters can be directly related to the vapor fraction surrounding a droplet during its ignition. Consequently, this study focuses on the influence of varying the composition of three well-known and abundantly used fuels. Different petroleum cuts were introduced in different fractions into isooctane, Jet A1 aviation fuel, and diesel fuel mixtures, which were then aerosolized into a uniformly distributed turbulent mist cloud and ignited using spark ignitors of 100 J. Subsequently, complementary tests were executed in a vertical flame propagation tube coupled with a high-speed video camera allowing the visualization of the flame and the determination of the spatial flame velocity, and a tentative estimation of the laminar burning velocity. The latter was also estimated from the pressure-time evolution in the 20 L sphere using existing correlations. Indeed, the determination of the laminar burning velocity can be useful in modeling such accidents. Finally, highlighting the essential role of the mist and vapor fraction during their ignition has led to a better understanding of their explosion mechanisms.

Structural Response of Double-Layer Steel Cylinders under Inside-Explosion Loading

The research on the structural response of explosive vessel is an important basis for the design of explosive vessels. Double-layer cylinder structures are widely used in the design of various explosive vessels. This paper studied the deformation of a steel cylindrical shell under internal explosion and proposes a new method for measuring shell deformation by PDV (photonic Doppler velocimetry). We carried out many spherical explosive experiments and obtained useful results that show displacement of the double-layer cylinders and the explosion time. The above process is a simulated LS-DYNA with a finite element numerical simulation. The vibration period of the outer cylindrical shell and the time for reflection of the stress wave in the outer cylindrical shell were obtained by numerical simulation and PDV measurement, respectively. The results of both can be verified against each other. Through the above research, the structural response of the multilayer cylinders can be obtained, which can provide further help with research of the structural design of multilayer cylinders.

Combustion and Explosion Characteristics of Pulverised Wood, Valorized with Mild Pyrolysis in Pilot Scale Installation, Using the Modified ISO 1 m3 Dust Explosion Vessel

Biomass is a renewable energy source with great potential worldwide and in the European Union. However, valorization is necessary to turn many types of waste biomass into a tradable commodity that has the potential to replace coal in power plants without significant modifications to firing systems. Mild pyrolysis, also known as torrefaction, is a thermal valorization process of low-quality biomass that could be suitable for such a purpose. In this work, typical Spruce-Pine-Fir residues from a sawmill were tested in terms of the explosion and flame propagation properties. The ISO 1 m3 dust explosion vessel was used, with a modified and calibrated dust dispersion system that could cope with very coarse particles. The deflagration index, Kst, was higher for the torrefied sample, with a peak at 36 bar m/s compared with 27 for the raw biomass. The peak flame speeds were similar for both samples, reaching 1 m/s. The peak Pmax/Pi was between 7.3 and 7.4 bar for both untreated and torrefied biomass. The mechanism for coarse particle combustion is considered to be influenced by the explosion-induced wind blowing the finer fractions ahead of the flame, which burns first, subsequently devolatilizing the coarser fractions.

Explosion suppression range and the minimum amount for complete suppression on methane-air explosion by heptafluoropropane

A visual explosion test system consisting of a 20 L explosion vessel and a horizontal pipeline of 6.5 m in length was adopted. The effects of heptafluoropropane (CF3CHFCF3) on methane-air explosion pressure, explosion flame structure and propagation velocity under different spraying ranges and amounts were systematically studied, and the suppression mechanism of CF3CHFCF3 on the methane-air explosion was analyzed. The experimental results show that the spraying range and amount of CF3CHFCF3 have a significant impact on the methane-air explosion. The presence of CF3CHFCF3 can promote the propagation of methane flame and increase the flame brightness under certain conditions. The reasonable setting of the spraying range and amount of CF3CHFCF3 can significantly weaken the explosion pressure of various parts in the pipeline. In the case of the same spraying amount of CF3CHFCF3, a larger CF3CHFCF3 spraying range not necessarily achieves the better the explosion suppression effect. Experimental analysis shows that in this experimental system, the explosion suppression effect of different spraying ranges from strongest to weakest at 1.72, 2.32 and 1.12 m, the minimum spraying amounts that can prevent 9.5 % methane-air premixed gas in the explosion suppression zone explosion flame propagation are 300, 300 and 360 mL, respectively.

Finding a way through the “misty” evaluation of the flammability and explosivity of kerosene aerosols

• JetA1 mist flammability and explosivity are assessed in a confined explosion vessel. • Influence of initial conditions on explosion sensitivity and severity is studied. • JetA1 mists with a small droplet size have a higher rate of pressure rise. • The MIE of JetA1 mist may be lower than that of vapors at low temperatures. • The vapor/liquid ratio of a mist is a key parameter of its explosion severity. In the context of assessing hydrocarbon mist ignition sensitivity and explosion severity, an original test method is proposed, focusing on kerosene JetA1 mists but is applicable to other hydrocarbons. Experiments were carried out in a modified apparatus based on the 20L explosion sphere. Fine control of the gas/liquid ratio and flow rates, the mist concentration, and the ignition energy and duration, was ensured by a specifically customized control system guaranteeing the flexibility and compliance of the test apparatus. The droplet size distribution (DSD) and the level of turbulence of the JetA1 mist cloud were first determined by an in-situ laser diffraction sensor and by Particle Image Velocimetry, respectively. The lower explosive limit (LEL), the minimum ignition energy (MIE), the limiting oxygen concentration (LOC), the maximum explosion overpressure (P max ), and the maximum rate of pressure rise (dP/dt max ) were then determined for different mist concentrations, ambient temperatures, initial turbulence levels, energies, and DSD. Tests showed that the LEL mist of JetA1 mists of an average diameter of 8 µm is around 94 g/m 3 , a value which increases to 220 g/m 3 with increasing DSD. This value also tends to decrease considerably with increasing temperatures. Moreover, at a JetA1 concentration of 125 g/m 3 , P max and dP/dt max as high as 6 bar and 192 bar/s respectively were reached, the latter increasing to about 480 bar/s at T = 60 °C. These mists were shown to be ignitable using energies as low as 200 mJ, which is lower than that of vapors at low temperatures, and a limiting concentration of oxygen of 15.8 % v/v . The potential presence of hydrocarbon mist should therefore be an element that requires reconsidering the classification of hazardous areas. Finally, to stress the influence of the vapor-liquid ratio present in the cloud before ignition on the combustion kinetics, an evaporation model based on the d 2 -law was developed estimating the evaporation time and the vapor quantity at different initial temperatures or droplet diameters. Findings were shown to be well coherent allowing the proposition of a new technique for determining hydrocarbon mist safety criteria. Finally, results have shown that JetA1 mists can ignite at temperatures below the liquid’s flashpoint under varying turbulence levels and droplet size distributions.