Maximum Rate Of Pressure Rise Research Articles

Influence of stearate dry coating on ibuprofen powder: What about the combustibility?

Dust explosion is one common type of process safety incident within the pharmaceutical industry. During powder processing, surface modification is widely used to increase dust flowability by alleviating inter-particle cohesion. However, it is currently unclear whether the addition of guest particles affects the combustibility of pharmaceutical powders. To investigate the explosion hazard of stearate-coated ibuprofen powder, this paper studied the ignition sensitivity and explosion severity of pure and coated ibuprofen by determining a series of explosion parameters in accordance with ASTM standards. The results indicated that the addition of stearate significantly reduced the minimum ignition energy of the mixture. Other parameters including the minimum ignition temperature, the minimum explosible concentration, the maximum explosion pressure, and the maximum rate of pressure rise were found to have less correlation with the improvement in dust flowability. Powder characterization through methods such as the Hausner ratio, scanning electron microscope, thermo-gravimetric analysis, and X-ray diffraction were employed to investigate chemical phase changes between coated mixtures and pure pharmaceuticals. The effects of improved dust flowability and dust dispersibility on the combustibility of ibuprofen dust were discussed to improve explosion-proof awareness in the pharmaceutical industry.

Damage power enhancement of fuel air explosive with typical metal hydrides additions

To study the damage power enhancement of fuel air explosive (FAE) with metal hydrides, the effects of metal hydrides (TiH2, MgH2, ZrH2) powders on shock wave and thermal damage of pure propylene oxide (PO) were explored using a 20 L spherical explosion test system combined with colorimetric thermometry technology. The experimental results showed that compared with the base metal powders, the explosion overpressures, maximum pressure rise rates and maximum average temperatures of the solid-liquid mixed fuel with the metal hydrides (TiH2, MgH2, ZrH2) powders increased by 11.04 %, 22.61 %, 4.80 % and 26.68 %, 38.18 %, 13.91 % as well as 6.85 %, 8.57 %, 1.34 %, respectively. Furthermore, the effects of metal hydride powders on the cloud explosion fuel were better than those of Al powders, and MgH2 powders had the most significant effects on the damage power enhancement of pure PO. Metal hydride powders as high-energy additives could improve the energy release characteristics of FAE.

A modified phosphorus-based inhibitor for dry water inhibitor and its chemical mechanisms in preventing benzoyl peroxide explosion

Dust explosions caused by benzoyl peroxide (BPO) pose a significant risk to the chemical industry, making the development of high-performance inhibitors essential. The effect of a novel inhibitor on the explosion behavior of BPO dust was studied through experiments and simulations. The chemical mechanism behind the suppressed BPO dust explosion was clarified. The primary explosion hazard of BPO stems from the instability of the oxygen–oxygen bond. To address this, a novel phosphorus-based dry water powder inhibitor, MAP-DW, was prepared which effectively captures key reactive radicals involved in the chain reaction. At the optimal explosion concentration of BPO, a concentration of 400 g/m3 of MAP-DW reduced the maximum explosion pressure and the maximum explosion pressure rise rate by 96.48 % and 99.58 %, respectively. The suppression effects of MAP-DW on the explosion of BPO dust include heat absorption, oxygen dilution, thermal insulation, and capture of key free radicals. The kinetic simulation results showed that the suppression cycle between phosphorus-containing substances captured key chain reaction radicals, and the coupled suppression among NH3, H2O, and phosphorus-containing substances dominated the suppression mechanism of MAP-DW on BPO dust explosion. This study provides new insights into the characterization and suppression of BPO dust explosion, while also supplying crucial data for the safe utilization of peroxides.

Computational investigation of combustion and emission characteristics of HCCI engine fueled with Carbon-Free NH3 –H2O2 blend

A computational investigation is provided of the utilization of blends of NH3 and H2O2 as carbonless fuels for HCCI combustion. A Computational Fluid Dynamics (CFD) model is developed and validated to assess the engine’s performance under varying proportions of NH3 and H2O2, equivalence ratios, and inlet temperatures. The heat release rate profiles demonstrated dual peaks, which were rationalized as an initial fuel decomposition followed by a slow thermal explosion and then a fast depletion of the fuel after the generation of a pool of OH radicals through decomposition of H2O2. Findings suggest that an increase in mole fraction of H2O2 advances combustion. Increasing the H2O2 volume fraction also decreases combustion duration, while increasing the IMEP. In-cylinder peak pressure and Maximum Pressure Rise Rate (MPRR) increase with H2O2 mole fraction, leading to reduced thermal efficiency, particularly at higher equivalence ratios, and an increased danger of uncontrolled combustion (knocking). Additionally, higher inlet mixture temperatures were shown to result in an advancement in the start of combustion and a reduction in combustion duration, with a corresponding increase in peak pressure. This points to the possibility of potentially controlling the notoriously difficult-to-control HCCI combustion through intake temperature for NH3/H2O2 fuel blends. However, increased NOx emissions are observed for increased intake temperature and in any case the NOx emissions are orders of magnitude above current regulatory limits, which means that practical engine operation will only be possible with an aftertreatment scheme based on the de-NOx activity of NH3.

Phase change materials as hydrogen explosion suppressants: An experimental and kinetic investigation

To investigate the potential application of phase change materials as H2 explosion suppressants, in the present work, the inhibition effect of Na2HPO4·12H2O, K2HPO4·3H2O, and Na2CO3·10H2O on H2 explosion were experimentally studied. The corresponding explosion suppression mechanism was calculated by using a comprehensive combustion model. Results showed that the selected phase change materials inhibited the H2 explosion, and Na2CO3·10H2O has the most significant effect for fuel-lean H2-air mixtures when 12 g was added. Of which the maximum explosion pressure (Pmax) and maximum rate of pressure rise (dp/dt)max were reduced by 26.6 % and 28.1 %, and maximum pressure increase time (tb) and peak pressure time(tc) were increased by 112.2 % and 120.3 %. The inhibition mechanism of Na2CO3·10H2O on H2 was revealed by numerical simulation. The adiabatic flame temperature (AFT) and laminar burning velocity (LBV) of H2-air mixture decrease with increasing hydrated salt addition, the free radicals H, O and OH have a decisive influence on the explosion process during which H decreases by 86.4 % at most. The chain initial reaction O + H2 ⇌ H + OH and the sodium-containing primitive reaction NaO + H + M ⇌ NaOH + M have the most significant influence on the combustion processes. The results of present work give a theoretical foundation for application the phase change materials in H2 explosion safety industry.

Investigation on the inhibition effect and mechanism of hydrogen explosion by 2-bromo-3,3,3-trifluoropropene

This study investigated the effect of 2-bromo-3,3,3-trifluoropropene (2-BTP, C3H2BrF3) on hydrogen explosion behavior through a combination of experiments and simulations. The maximum explosion pressure (pmax), maximum pressure rise rate ((dp/dt)max), and critical inhibition concentration (CIC), across different equivalence ratios (Φ) and inhibitor concentrations (V), were obtained via experiments. The changes in adiabatic flame temperature, mole fraction of active radicals and sensitivity coefficient throughout the reaction were analyzed using CHEMKIN. The fuel-like properties of 2-BTP and the carbon monoxide (CO) produced by decomposition led to a promoting effect on the lean hydrogen explosion, primarily due to the elementary reactions R31, R806 and R882. When Φ≥1.0, the capture of active radicals via elementary reactions such as R908, R1507, and R88 was enhanced, resulting in the dominance of inhibition and a corresponding inhibitory effect. Notably, 2-BTP exhibited an inhibitory effect for (dp/dt)max at any equivalence ratio. The CIC decreased from 10% to 4% when increasing equivalence ratios from 0.6 to 2.0. This work provides crucial data and a theoretical foundation for the prevention and control of hydrogen explosions.

Effect of ignition timing and hydrogen injection phase on HDI engine combustion and NOx emissions

ABSTRACT In order to improve the ITE and reduce NOx emissions in direct-injected hydrogen (HDI) engines under at medium and high loads, the effects of IT and hydrogen injection phase on the combustion and NOx emission characteristics of the HDI engine at high rpm and medium load were investigated numerically. The base engine is a four-cylinder turbocharged direct-injected gasoline (GDI) engine, which is modified into a HDI engine with direct-injected hydrogen fuel. The simulation is performed using GT-Power software. The operating condition of HDI engine is set to 5500 rpm and 50% load. Firstly, IT is optimized, and then based on the IT optimization results, the hydrogen injection phase is optimized. The results show that as the IT is advanced, the maximum pressure rise rate (MPRR) shows a gradual increasing trend, while the combustion intensity and the indicated thermal efficiency (ITE) increases firstly and then decreases, and the former reaches a maximum value at 25° CA BTDC, while the latter reaches a maximum value of 40.5% at 18°CA BTDC. In addition, the nitrogen oxide (NOx) emissions decrease as the IT is delayed. Based on 18°CA BTDC of IT, the results indicated that the later the moment of hydrogen injection, the higher the MPRR, resulting in the greater the knock intensity. The ITE is less affected by the hydrogen injection phase. When the hydrogen injection phase is delayed, NOx emissions increase slightly.

Fire safety characteristics of natural gas with hydrogen admixture

The increasing pressure to decarbonise energy production leads to the need to use low or zero carbon fuels or energy carriers. One of the promising fuels of the future is hydrogen, which is carbon-free if renewable energy sources are used for its production. However, the capacity for hydrogen production is currently insufficient to make it applicable on a large scale. Adding hydrogen to natural gas allows for a reduced carbon footprint without costly modifications to pipeline distribution network. However, changing the composition of gas in transport and distribution facilities requires a thorough assessment of the impact on operational safety. Fire safety of flammable mixtures is commonly assessed on the basis of explosive limits and other parameters. Although methods are available to calculate these parameters based on the composition of the mixtures being evaluated, the final safety assessment should rely on actual measured values. The scope of this work is to determine the explosion limits of natural gas from the transit system and changes in the limits caused by the addition of hydrogen at the concentration levels of 10% and 20% (v/v). Obtained experimental results were further compared with theoretically calculated values. Attention was also paid to the change in maximum explosion pressure, maximum pressure rise rate and oxygen concentration limits (LOC). As a result, valuable data on the expansion of the explosion limits of natural gas after the addition of hydrogen are presented.

Explosion mechanism of HMX dust within a tank and its comparative analysis of explosion characteristics with IPN mist

This study establishes a numerical model for dust flow and dust cloud explosion, elucidating the mechanisms underlying HMX dust cloud explosions and the variations in explosion parameters concerning concentration and particle size. Furthermore, it compares HMX dust's explosion parameters with IPN mist's. The findings can be a pivotal basis for the design of explosive compositions and accident prevention. As the concentration increases, both the maximum explosion pressure (Pmax) and the maximum rate of pressure rise ((dP/dt)max) of HMX dust undergo significant increases. As the particle size increases, Pmax and (dP/dt)max for HMX dust exhibit no significant variations. When the concentrations of HMX dust and IPN mist are 400 g/m3, there are no significant differences in their Pmax and (dP/dt)max. However, when the concentrations of HMX dust and IPN mist are 100 g/m3, the hazards of IPN mist are higher than those of HMX dust.

Study on the impacts of injection parameters on knocking in HPDI natural gas engine at different combustion modes

Based on three-dimensional (3D) computational fluid dynamics (CFD) software, a 3D numerical model was constructed to investigate the effects of injection timing, pilot diesel energetic ratio (PDER), and angle between the central axis of the diesel jet and the horizontal direction (α) on combustion and knock in the natural gas mixing-limited combustion (NMLC) mode and natural gas slightly premixed combustion (NSPC) mode. The results indicate that advancing the start of injection of natural gas (NSOI) leads to a slight improvement in indicated thermal efficiency (ITE), but also an increase in peak cylinder pressure (Pmax) and maximum pressure rise rate (MPRR). In the NMLC mode, as the diesel and natural gas injection interval (IDN) decreases, the interference between the diesel and natural gas jets intensifies, ultimately leading to instability in the flame propagation process and increased fluctuations in cylinder pressure. At different NSOIs, when IDN is 0°CA, the maximum amplitude of pressure oscillations (MAPO) is the highest. When the PDER is increased from 5 % to 15 %, ITE increases by 7.1 %. Under different combustion modes, as α increases, ITE first increases and then decreases. However, the NSPC mode achieves a higher ITE, reaching up to 44.4 %.

Experimental and numerical study on the combustion characteristic of H2 and CH4 in oxygen-enriched environment

Oxygen-enriched combustion could rise the hazard of unexpected fire and explosion in industry. This study experimentally and numerically analyzed the combustion characteristic of H2 and CH4 in oxygen-enriched environment (Ω = 21%–100 %). For H2 at Φ = 1 and Ω = 100 %, the maximum explosion pressure and maximum pressure rise rate were about 3.89 MPa and 1259.2 MPa/s. For CH4, these values were about 4.77 MPa and 6279.4 MPa/s. The upper flammability limit of gases increased sharply with the increase of Ω, however, the lower flammability limit was almost unchanged. Besides, the increasing of Ω also could result in the rising of aforementioned combustion parameters. The sensitivity of burning velocity was also analyzed. For H2 flame at Φ = 0.8, R35 could slow down burning velocity when Ω = 21 %, but promote it when Ω = 30 % and 70 %. For CH4 flame at Φ = 1.4, the sensitivity coefficients of R11, R35, R43 and R84 changed from negative to positive when Ω increased from 21 % - 30 %–70 % - 100 %. It was concluded that the oxygen concentration not only affect the inert gas but also affect the reaction kinetic of flame.

Assessing the potential and energy distribution calibration of ethanol-biodiesel based RCCI mode of compression ignition engine in a plugin parallel hybrid electric vehicle

The focus of this research is to develop the resilient powertrain to combat the enforcement of stringent emission regulations and elevate its feasibility to power with the sustainable fuels to support the fuel crisis. The current solution in the reliable and adaptability point of view is the low temperature combustion engine-based hybrid electric powertrain powered with sustainable fuel is the better choice. The present work proposes the concept of an ethanol-biodiesel fuel based RCCI plugin parallel hybrid electric vehicles (PHEVs). The significant examination of this work in the aspects of optimal torque structure and injector control parameter calibration. The calibration of the RCCI engine torque structure operation is performed based on the multi-objective constraints of variance of indicated mean effective pressure and the maximum rate of pressure rise for the combustion stability. While the equivalence ratio and combustion temperature with emphasis on limiting the amount of NOx and soot emissions. The maximum ethanol energy share proportion of 66.98% has been achieved. The RCCI engine is most frequently operating in the torque zone of 10 Nm and then 17.81 Nm while the BLDC motor is most frequently operated in the range of 55 Nm even at max torque of 60 Nm. When comparing to a standard diesel hybrid setup, the ethanol-biodiesel fuelled RCCI setup has a 18%–19% reduction in harmful NOx emissions, with an equivalent decrease of 22.7% in fuel economy. This is achieved by only having a 13.4% more CO emission while a minimal increase in soot emission throughout the overall course of the driving cycle. The result of this work shows evidence that implementing an ethanol-biodiesel fuelled RCCI engine in a parallel hybrid configuration achieves a significant reduction in NOx emissions while achieving the performance targets and managing the fuel and battery energy utilization over a driving cycle efficiently.

The performance of a spark ignition gasoline engine with hydrogen addition under low-load conditions

With continuously increasing populations and industrialization, more and more green consumers and stringent emission regulations promote low-carbon or zero-carbon alternative fuels in transportation sector. Hydrogen is considered carbon-free when produced using environmentally friendly methods, and could achieve zero carbon emission in the internal combustion engines. This study comprehensively explores the influences of the hydrogen addition on the performance of the gasoline spark ignition (SI) engine operated at low-load conditions. The experimental results showed that the abnormal combustion cycles of the test gasoline engine are greatly reduced with hydrogen enrichment. In addition, the coefficient of variation (COV) of the indicated mean effective pressure (IMEP) of the gasoline engine is 2.66 % under the 1500 rpm and 0.2 Mpa (brake mean effective pressure: BMEP) condition, while the COV of IMEP of the engine fuelled with gasoline and hydrogen is 2.34 % at the same condition. Furthermore, the knocking intensity of the gasoline engine is strengthened by adding hydrogen because the averaged maximum pressure rise rate (MPRR) of the gasoline SI engine is slightly increased. Besides, the indicated thermal efficiency (ITE) of the gasoline engine is increased 0.9 % and its maximum increase rate of the ITE is 4.27 % with hydrogen addition at the 1300 rpm and 0.2 MPa condition. Last, unburned HC, CO, and CO2 of the gasoline engine are reduced while NOx emissions increase with adding hydrogen due to high combustion temperature.

Effect of large particle mixing on cloud ignition and explosion of fine rice husk

Large particles mixed with fine dust are commonly found in the processing and transportation of grain dust. The mixture of dust is exposed to the risk of dust explosions when suspended in the environment. Using a 20 L spherical explosion device and the dust cloud minimum ignition energy (MIE) experimental platform, this study examines the effects of crushed brown rice mixture on the ignition and explosion of fine rice husk dust. The discovery of large granules of crushed brown rice being lifted up to form flow "obstacles" in the mixed dust cloud has a similar inhibitory effect to inert materials, causing the MIE of the dust cloud to increase from 40 mJ to 150 mJ. However, 5 % of crushed brown rice will lower the 10 mJ dust cloud's ignition energy when the concentration of dust clouds is 500 g/m3. Through testing the dispersibility of mixed dust clouds, it was found that fine dust particles adsorbed on the surface of large particles will peel off after being lifted, improving the dispersibility of the mixed dust cloud and forming a system of mixed dust clouds with finer effective particle size, thereby promoting ignition. Furthermore, due to the improvement in the dispersibility of mixed dust clouds by large particles, at mixing ratios below 30 %, large particles will also significantly increase the maximum rate of pressure rise (dP/dt)max, increasing the likelihood of dust ignition and the consequences of an explosion. Therefore, these findings should be taken into consideration during the process of grain processing and transportation.

Oxyhydrogen-air explosion characteristics in water jetting propulsion

Hydrogen has attracted many researchers in the field of explosion jetting propulsion owing to its appealing advantages of zero carbon emissions, wide flammability range, and ease of preparation. However, the research gap in hydrogen explosion characteristics in water jetting scene has slowed down the advancement of the impulsive jetting propulsion field. In this work, static tests under three typical explosion jetting scenes (vertical submerged jetting, oblique submerged jetting, and aerial jetting) are conducted to reveal their explosion and thrust characteristics. The static tests results demonstrate that although the peak pressures of the aerial and vertical submerged explosion jettings are comparable, the peak thrust of the former is dramatically reduced by 40.6 %. We also find that the maximum pressure rise rate and peak pressure of the oblique submerged jetting are 22.9 % and 11.4 % lower than those of the vertical submerged jetting, respectively. Meanwhile, the peak thrust of the inclined jetting is also reduced by 14.1 % compared to the vertical jetting. High-speed photography applied to capture the evolution details of the oxyhydrogen-air explosion reveals that the preceding differences are attributed to the asymmetrical water repulsion phenomenon. Specific impulse is used to characterize the propulsion performance of the oxyhydrogen-air–water explosion jetting at varied volume fractions, and the results show that the maximum specific impulse is obtained for a given 0.45 kg thruster at 40 % water volume and 4:6 ratio of air to oxyhydrogen. The correctness of the explosion characterization metrics and thrust results are finally corroborated via the outdoor aquatic-aerial jetting propulsion tests.

Comprehensive effects of ammonia substitution rate, compression ratio, and ignition timing on knock, NOx emissions and indicated thermal efficiency in a hydrogen fuel engine

AbstractTo reduce knock and keeping low NOx emissions and high indicated thermal efficiency (ITE) in a hydrogen fuel engine, the comprehensive effects of ammonia substitution rate (ASR), compression ratio (CR), and ignition timing (IT) on its combustion and its NOx emissions were studied numerically. Based on a four‐cylinder gasoline direct injection (GDI) engine, it was modified into an ammonia/hydrogen dual‐fuel (AHDF) spark ignition (SI) engine. The simulation was conducted by GT‐Power software, and simulation data were validated through experiments. 2500 rpm_50% load was selected for the research. ASR, CR and IT vary from 0% to 20%, 10.5 to 8.5, and −24 to 0°CA ATDC, respectively. The findings indicate that increasing ASR decreases the maximum pressure rise rate (MPRR) and the knock index (KI), improving the ITE, but increasing NOx emissions. Based on 20% ASR, CR was optimized. The findings indicate that decreasing CR reduces the MPRR and KI, but increasing NOx emissions and decreasing the ITE. Finally, based on CR of 9, IT was optimized. The findings indicate that delaying IT reduces the MPRR and KI, but also has a certain impact on NOx emissions and ITE. After compromise consideration, the optimal IT in this study was selected as −9°CA ATDC.

Safely and Efficiently Prepare Environmental-Friendly Gas Generator with High Gas Production Performance

ABSTRACT Excellent gas generation and boost rate, low residue rate, and low burning temperature, as well as stable combustion, have always been the key performance of gas generators in the effective functioning of automotive airbag systems. Under the conditions of material properties, formulation, and charge structure being determined, how to safely prepare gas generators with closely contacting component interfaces has become a necessary problem to solve. In this study, vacuum freeze-drying technology was used to prepare KNO3/5 aminotetrazole (5-AT) and KNO3/nitroguanidine (NQ) gas generators. The whole process effectively avoids high temperature and thus ensures operational safety. Compared to physically and mechanically mixed agents, the agents prepared through freeze-drying exhibit stable combustion, with a nearly doubled combustion speed and a reduction of nearly 100°C in combustion temperature. The residual rates of KNO3/5-AT and KNO3/NQ after combustion prepared through freeze-drying are 2.55% and 3.30%, respectively, indicating a more complete combustion process. The maximum combustion pressures reach 97.18 MPa and 88.15 MPa, respectively, with a significant increase in the maximum pressure rise rate. Consequently, the prepared gas generators demonstrate enormous potential in automotive airbag systems.

A comparative study of the effect of cavity and obstacle on premixed methane–air flame evolution

To compare the effect of the cavity and obstacle on the flame evolution, a series of experimental studies are carried out to investigate the premixed methane-air flame propagation in the combustion chamber featured by cavity or obstacle. The flame behavior is obtained by analyzing the flame-front dynamics and pressure variation. The flame stretches into an inclined shape due to the flow contraction with the presence of an obstacle. In contrast, the flame forms a vortex by following the unburned gas vortex owing to the flow expansion in a cavity. Furthermore, the flame downstream of the obstacle is more turbulent than in cavity cases. Moreover, the flow contraction caused by obstacles also contributes to a higher flame-tip velocity than cavity cases. When the change in cross-section caused by obstacle and cavity is equivalent, the maximum pressure in the combustion chamber with an obstacle is generally larger than that in cavity cases ascribed to the combined effect of the changes in fuel amount and heat loss. In addition, the maximum rate of pressure rise in the combustion chamber featured by the obstacle is larger than that in the combustion chamber featured by a cavity, corresponding to the highly turbulent flame downstream of the obstacle.

Effects of buoyancy on the spherical flame and explosion pressure of a CH4 mixture under dilution conditions

To determine the effects of buoyancy on the spherical flame and explosion pressure under dilution conditions, a series of explosion experiments were conducted in a 20-L spherical container. The schlieren technique was used to record CH4 flames to assess the buoyancy effect. The change in the explosion pressure was recorded and correlated with the flame shape to analyze the explosion characteristics. The methane explosion occurred in two stages: initial ignition and flame development. During initial ignition, the addition of CO2 caused the flame buoyancy to increase considerably. Flames with different buoyancies had different shapes, such as spherical, ellipsoidal, and “ω” shapes. The radius of the flame at 12 mm may serve as the threshold for the onset of buoyancy effects; once the radius exceeds this value, the flame could deform due to buoyancy effects. Increasing the added CO2 concentration caused the buoyancy effect to be enhanced and appear at a very low radius of the flame. The combined effects of buoyancy and dilution reduced the flame expansion speed. The difference between the horizontal and upward expansion speeds linearly increased with the CO2 concentration. At a high CO2 concentration, the flame stagnated at speeds below 0.5 m/s. During flame development, CO2 addition made the flame surface smoother. Suppressing the cellular flame structure delayed the maximum explosion pressure rise rate and reduced the pressure peak. A coupled analysis of the flame shape and the maximum explosion pressure rise rate showed a dense cellular structure for a high explosion pressure rise rate and a smooth flame surface for a low maximum explosion pressure rise rate. The size and number of cellular structures for different mixtures were similar at a fixed maximum explosion pressure rise rate.

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.