2009 Vol. 29, No. 3
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2009, 29(3): 225-230.
doi: 10.11883/1001-1455(2009)03-0225-06
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Abstract:
The present paper discusses the ratios of DOP (depth of penetration) of different targets under the same penetration condition according to the dimensionless formula of DOP of different targets penetrated by a non-deformable projectile. It is declared that various targets may be equivalent to each other. Finally we discuss the applicable range of the equivalence and the feasibility of targets substitution by integrating the available test data.
The present paper discusses the ratios of DOP (depth of penetration) of different targets under the same penetration condition according to the dimensionless formula of DOP of different targets penetrated by a non-deformable projectile. It is declared that various targets may be equivalent to each other. Finally we discuss the applicable range of the equivalence and the feasibility of targets substitution by integrating the available test data.
2009, 29(3): 231-236.
doi: 10.11883/1001-1455(2009)03-0231-06
Abstract:
The 6.35-mm-diameter aluminum spheres were driven by a two-stage light-gas gun to normally penetrate aluminum sheets at the impact velocities of 2.23~5.26 km/s. The flash radiographs of the impact-induced debris clouds were presented and analyzed to describe the features of deforma-tion and fragmentation of the aluminum spheres. The propagation of the stress waves in the aluminum spheres was qualitatively explained, and the three statuses of spheres were observed under the different impact conditions. In the plastic deformation stage, the deformation of the aluminum spheres gets more distinct as the impact velocity and the sheet thickness increase. The critical impact velocity at which the principle part of the aluminum sphere began to shatter decreases with the increase of the sheet thickness, and this velocity is independent of the sheet thickness more than a certain value. In the complete fragmentation stage, with the increase of the impact velocity, the radial velocities and the fragment number for the principle part of sphere increase, and the fragment sizes decrease.
The 6.35-mm-diameter aluminum spheres were driven by a two-stage light-gas gun to normally penetrate aluminum sheets at the impact velocities of 2.23~5.26 km/s. The flash radiographs of the impact-induced debris clouds were presented and analyzed to describe the features of deforma-tion and fragmentation of the aluminum spheres. The propagation of the stress waves in the aluminum spheres was qualitatively explained, and the three statuses of spheres were observed under the different impact conditions. In the plastic deformation stage, the deformation of the aluminum spheres gets more distinct as the impact velocity and the sheet thickness increase. The critical impact velocity at which the principle part of the aluminum sphere began to shatter decreases with the increase of the sheet thickness, and this velocity is independent of the sheet thickness more than a certain value. In the complete fragmentation stage, with the increase of the impact velocity, the radial velocities and the fragment number for the principle part of sphere increase, and the fragment sizes decrease.
2009, 29(3): 237-242.
doi: 10.11883/1001-1455(2009)03-0237-06
Abstract:
Numerical investigations were conducted by using the explicit dynamic finite element method. In numerical simulations, the honeycomb specimen was divided into nine regions by referring the local deformation modes of a perfect hexagonal honeycomb under different impact velocities. Based on the above treatment, the influences of the defects (cell wall missing) in different regions on the in-plane dynamic properties of honeycombs were discussed. The results show that except for the cell wall missing ratio, the dynamic performance of the honeycomb relies on the defect location. Especially under middle or low impact velocities, it displays higher sensitivity. The plateau stress relates to the cell wall missing ratio and the impact velocity, whose sensitivity is determined by the defect location.
Numerical investigations were conducted by using the explicit dynamic finite element method. In numerical simulations, the honeycomb specimen was divided into nine regions by referring the local deformation modes of a perfect hexagonal honeycomb under different impact velocities. Based on the above treatment, the influences of the defects (cell wall missing) in different regions on the in-plane dynamic properties of honeycombs were discussed. The results show that except for the cell wall missing ratio, the dynamic performance of the honeycomb relies on the defect location. Especially under middle or low impact velocities, it displays higher sensitivity. The plateau stress relates to the cell wall missing ratio and the impact velocity, whose sensitivity is determined by the defect location.
2009, 29(3): 243-248.
doi: 10.11883/1001-1455(2009)03-0243-06
Abstract:
On the basis of the multi-fluid volume-of-fraction method and piecewise parabolic method, a multi-viscosity-fluid piecewise parabolic method(MVPPM) was proposed and the corresponding computer code was developed to investigate the multi-viscous-fluid dynamic problems. To verify and validate the developed code, a shock tube experiment of hydrodynamic instability and flow mixing induced by reshock was simulated numerically. The numerical results are in agreement with the experimental results. The evolution of the fluid mixing zone under reshock reveals that the mixing growth rate has a close dependence on the spectra and amplitudes of the initial perturbation, and at the moment the reshock arrives at and interacts with the interface, the fluid mixing zone width decreases sharply, then increases quickly again. Comparison between viscous and inviscid results displays that the molecular dynamics viscosity affects weakly on the fluid mixing zone.
On the basis of the multi-fluid volume-of-fraction method and piecewise parabolic method, a multi-viscosity-fluid piecewise parabolic method(MVPPM) was proposed and the corresponding computer code was developed to investigate the multi-viscous-fluid dynamic problems. To verify and validate the developed code, a shock tube experiment of hydrodynamic instability and flow mixing induced by reshock was simulated numerically. The numerical results are in agreement with the experimental results. The evolution of the fluid mixing zone under reshock reveals that the mixing growth rate has a close dependence on the spectra and amplitudes of the initial perturbation, and at the moment the reshock arrives at and interacts with the interface, the fluid mixing zone width decreases sharply, then increases quickly again. Comparison between viscous and inviscid results displays that the molecular dynamics viscosity affects weakly on the fluid mixing zone.
2009, 29(3): 249-254.
doi: 10.11883/1001-1455(2009)03-0249-06
Abstract:
The dynamic response of a cylindrical explosion containment vessel with the elliptical cover under four kinds blast loading was studied using explicit finite element code LS-DYNA. The results show that for the ideal structure that only include a cylinder and an elliptical cover, the strain of the points on the plane which across the center of the vessel has become the largest during the initial stage. When adding a certain mass flange on the vessel, the strain growth phenomenon has shown up on the above points. The strain growth and the mass of the flange are the factors that must be considered when designed.
The dynamic response of a cylindrical explosion containment vessel with the elliptical cover under four kinds blast loading was studied using explicit finite element code LS-DYNA. The results show that for the ideal structure that only include a cylinder and an elliptical cover, the strain of the points on the plane which across the center of the vessel has become the largest during the initial stage. When adding a certain mass flange on the vessel, the strain growth phenomenon has shown up on the above points. The strain growth and the mass of the flange are the factors that must be considered when designed.
2009, 29(3): 255-260.
doi: 10.11883/1001-1455(2009)03-0255-06
Abstract:
The experiment, mechanism analysis and numerical simulation were conducted to systemically explore impulsive thermomechanical response of parabolic laser thrusters for air-breathing mode laser propulsion. Based on analysis on the four thermal loads of incident, radiation, transmission and convection consisting in laser propulsion, the corresponding thermal mechanical coupling and dynamic computational method was established. The temperature rises of thrusters loaded by multi-pulses agree well with the experimental results. The computational results indicate that the incident absorption and high-temperature radiation are the prime reasons for the temperature rise of the parabolic laser thrusters. Researches show that the thrusters will go through the tensile failure before their melting, which open out the mechanism and the severity of the thermal-mechanical shock damage.
The experiment, mechanism analysis and numerical simulation were conducted to systemically explore impulsive thermomechanical response of parabolic laser thrusters for air-breathing mode laser propulsion. Based on analysis on the four thermal loads of incident, radiation, transmission and convection consisting in laser propulsion, the corresponding thermal mechanical coupling and dynamic computational method was established. The temperature rises of thrusters loaded by multi-pulses agree well with the experimental results. The computational results indicate that the incident absorption and high-temperature radiation are the prime reasons for the temperature rise of the parabolic laser thrusters. Researches show that the thrusters will go through the tensile failure before their melting, which open out the mechanism and the severity of the thermal-mechanical shock damage.
2009, 29(3): 261-267.
doi: 10.11883/1001-1455(2009)03-0261-07
Abstract:
Concrete is regarded as a two-phase composite constaining coarse aggregate particles and mortar matrix. The mortar matrix and coarse aggregate particles are assumed to be elastic, homogeneous and isotropic. Coarse aggregate particles are spherical. Based on the Mori-Tanaka concept of average stress and Eshelby equivalent inclusion theory, the elastic modulus of concrete is formulated. Using Horii and Nemat-Nasser sliding crack model of brittle materials subjected to biaxial compressive stress, the influences of micro-crack on elastic modulus and damage evolution are found out by the meso-mechanical method. A one-dimensional dynamic constitutive model of concrete subjected to impacting loading is established. It agrees well with the experimental results. So it can be used to simulate the dynamic mechanical behaviors of concrete under impact loading.
Concrete is regarded as a two-phase composite constaining coarse aggregate particles and mortar matrix. The mortar matrix and coarse aggregate particles are assumed to be elastic, homogeneous and isotropic. Coarse aggregate particles are spherical. Based on the Mori-Tanaka concept of average stress and Eshelby equivalent inclusion theory, the elastic modulus of concrete is formulated. Using Horii and Nemat-Nasser sliding crack model of brittle materials subjected to biaxial compressive stress, the influences of micro-crack on elastic modulus and damage evolution are found out by the meso-mechanical method. A one-dimensional dynamic constitutive model of concrete subjected to impacting loading is established. It agrees well with the experimental results. So it can be used to simulate the dynamic mechanical behaviors of concrete under impact loading.
2009, 29(3): 268-274.
doi: 10.11883/1001-1455(2009)03-0268-07
Abstract:
A special experiment system was designed to carry out an experimental investigation about gasoline-air mixture ignition phenomena induced by the hot wall in a confined space. According to experimental results, the ignition manner of gasoline-air mixture, the critical ignition temperature and the ignition pressure region and the change laws of concentration, temperature in the course of fire were discussed in detail. It is found that the ignition course of gasoline-air mixture in the confined space is divided into three phases, namely, gasoline steam pyrolysis, oxidation reaction, accelerated oxidation. There are three ignition manners of gasoline-air mixture caused by the hot wall, namely combustion, deflagration, and explosion. Gasoline-air mixture in the confined space starts its rapid chemical reaction at the spontaneous combustion temperature of gasoline. And its ignition temperature is about 80 K higher than spontaneous combustion point of gasoline. Regardless of region of the fire, or other region in the confined space, there is a sudden rise of temperature at the time of ignition. When the temperature of the hot wall reach 773～873 K, there is a triangle pressure peninsula of thermal ignition of gasoline-air mixture, where the ignition pressure region is of 2.2～17.6 kPa.
A special experiment system was designed to carry out an experimental investigation about gasoline-air mixture ignition phenomena induced by the hot wall in a confined space. According to experimental results, the ignition manner of gasoline-air mixture, the critical ignition temperature and the ignition pressure region and the change laws of concentration, temperature in the course of fire were discussed in detail. It is found that the ignition course of gasoline-air mixture in the confined space is divided into three phases, namely, gasoline steam pyrolysis, oxidation reaction, accelerated oxidation. There are three ignition manners of gasoline-air mixture caused by the hot wall, namely combustion, deflagration, and explosion. Gasoline-air mixture in the confined space starts its rapid chemical reaction at the spontaneous combustion temperature of gasoline. And its ignition temperature is about 80 K higher than spontaneous combustion point of gasoline. Regardless of region of the fire, or other region in the confined space, there is a sudden rise of temperature at the time of ignition. When the temperature of the hot wall reach 773～873 K, there is a triangle pressure peninsula of thermal ignition of gasoline-air mixture, where the ignition pressure region is of 2.2～17.6 kPa.
2009, 29(3): 275-280.
doi: 10.11883/1001-1455(2009)03-0275-06
Abstract:
Based on the sound velocity measurement theory, using RSM-SY5 intelligent sound wave apparatus, damage of the surrounding rock under blasting load in a strip iron mine was studied by in-situ tests on sound waves. It is shown that the damage range of the surrounding rock caused by blasting excavation is 7 m in this strip iron mine, and the damage degree decreases with the increase of the distance of the surrounding rock from the blasting center. The sound velocity in rock mass decreases gradually with the increase of the blasting times and it means that the repeated blasting loads present a cumulative damage effect to rock mass. The cumulative damage is not the simple addition of the damage induced by the repeated single blasting loads, and takes on a non-linear increase. And the shorter the distance of the rock mass from the blasting center is, the more distinct the cumulative damage effect is.
Based on the sound velocity measurement theory, using RSM-SY5 intelligent sound wave apparatus, damage of the surrounding rock under blasting load in a strip iron mine was studied by in-situ tests on sound waves. It is shown that the damage range of the surrounding rock caused by blasting excavation is 7 m in this strip iron mine, and the damage degree decreases with the increase of the distance of the surrounding rock from the blasting center. The sound velocity in rock mass decreases gradually with the increase of the blasting times and it means that the repeated blasting loads present a cumulative damage effect to rock mass. The cumulative damage is not the simple addition of the damage induced by the repeated single blasting loads, and takes on a non-linear increase. And the shorter the distance of the rock mass from the blasting center is, the more distinct the cumulative damage effect is.
2009, 29(3): 281-288.
doi: 10.11883/1001-1455(2009)03-0281-08
Abstract:
By changing the jacket, the filler and the impact velocity of the PELE projectiles, the impact behaviors of the PELE projectiles perpendicularly perforating thin target plates were investigated experimentally. On the basis of the experimental results, the stresses of the PELE projectiles during their penetration into the targets were analyzed and the lateral effect production mechanism was illuminated. On some hypotheses, the theoretic models were established for the residual and radial velocities of PELE projectiles penetration into thin targets. The calculated results by the established models are in approximate agreement with the experimental results. The theoretical and experimental investigations show that the ratio of the compressive-to-tensile strength of the jacket, the Poissons ratio and elastic modulus of the filling material, and the impact speed of the PELE projectile affect the lateral effect markedly.
By changing the jacket, the filler and the impact velocity of the PELE projectiles, the impact behaviors of the PELE projectiles perpendicularly perforating thin target plates were investigated experimentally. On the basis of the experimental results, the stresses of the PELE projectiles during their penetration into the targets were analyzed and the lateral effect production mechanism was illuminated. On some hypotheses, the theoretic models were established for the residual and radial velocities of PELE projectiles penetration into thin targets. The calculated results by the established models are in approximate agreement with the experimental results. The theoretical and experimental investigations show that the ratio of the compressive-to-tensile strength of the jacket, the Poissons ratio and elastic modulus of the filling material, and the impact speed of the PELE projectile affect the lateral effect markedly.
2009, 29(3): 289-294.
doi: 10.11883/1001-1455(2009)03-0289-06
Abstract:
To explore the compaction mechanism of porous materials under explosive loading, the process of the circular shape pore collapse in oxygen-free copper was numerically simulated by using the LS-DYNA finite element code. Simulated results indicate that explosive welding and jet penetration can appear in the different boundary regions during pore collapse under the shock pressure of 6 GPa. These two bonding modes can improve the bonding compactness of the boundary material and enhance the density and mechanical strength of the block materials obtained by explosive compaction possess.
To explore the compaction mechanism of porous materials under explosive loading, the process of the circular shape pore collapse in oxygen-free copper was numerically simulated by using the LS-DYNA finite element code. Simulated results indicate that explosive welding and jet penetration can appear in the different boundary regions during pore collapse under the shock pressure of 6 GPa. These two bonding modes can improve the bonding compactness of the boundary material and enhance the density and mechanical strength of the block materials obtained by explosive compaction possess.
2009, 29(3): 295-299.
doi: 10.11883/1001-1455(2009)03-0295-05
Abstract:
An oxygen-free high-conductivity copper(OFHC) cylinder was driven by a single-stage gun to impact OFHC plates at the velocity of 205 m/s. The longitudinal stress-time traces in the plates were recorded by the manganin stress gauge and the recovered samples were observed. And the longitudinal stress-time traces in the plates were computed by using the Johnson-Cook(J-C), Zerilli-Armstrong(Z-A) and Steinberg-Cochran-Guinan(S-C-G) constitutive models. Comparison between the experimental and computational results indicates that the peak stresses in the plates computed by the three constitutive models are consistent with the experiments, while the deformations of the cylinder computed by the Z-A and S-C-G models, are more agreeable to the experiments than the J-C model. but, when the impact velocity is 500 m/s, the computed results by the three constitutive models appear markedly different from one another.
An oxygen-free high-conductivity copper(OFHC) cylinder was driven by a single-stage gun to impact OFHC plates at the velocity of 205 m/s. The longitudinal stress-time traces in the plates were recorded by the manganin stress gauge and the recovered samples were observed. And the longitudinal stress-time traces in the plates were computed by using the Johnson-Cook(J-C), Zerilli-Armstrong(Z-A) and Steinberg-Cochran-Guinan(S-C-G) constitutive models. Comparison between the experimental and computational results indicates that the peak stresses in the plates computed by the three constitutive models are consistent with the experiments, while the deformations of the cylinder computed by the Z-A and S-C-G models, are more agreeable to the experiments than the J-C model. but, when the impact velocity is 500 m/s, the computed results by the three constitutive models appear markedly different from one another.
2009, 29(3): 300-305.
doi: 10.11883/1001-1455(2009)03-0300-06
Abstract:
According to the characteristics of short-time, non-stationary random signals, the wavelet packet energy spectra for the measured blasting vibration signals were investigated by using the wavelet packet analysis. These blasting vibration signals were produced in case of the different explosion parameters such as the distance of the measuring point from the blasting center, the maximum sectional explosive mass and the millisecond-delay detonator number. The energy distributions at the different frequency bands for the blasting vibration signals were obtained. The energy distribution characteristics of the blasting vibration signals measured under the different explosion parameters were analyzed. Considering the blasting vibration signal energy, the attenuation laws of the blasting seismic waves corresponding to the different explosion parameters were explored. Our results indicate that the wavelet packet analysis method is effective to study blasting seismic effects.
According to the characteristics of short-time, non-stationary random signals, the wavelet packet energy spectra for the measured blasting vibration signals were investigated by using the wavelet packet analysis. These blasting vibration signals were produced in case of the different explosion parameters such as the distance of the measuring point from the blasting center, the maximum sectional explosive mass and the millisecond-delay detonator number. The energy distributions at the different frequency bands for the blasting vibration signals were obtained. The energy distribution characteristics of the blasting vibration signals measured under the different explosion parameters were analyzed. Considering the blasting vibration signal energy, the attenuation laws of the blasting seismic waves corresponding to the different explosion parameters were explored. Our results indicate that the wavelet packet analysis method is effective to study blasting seismic effects.
2009, 29(3): 306-311.
doi: 10.11883/1001-1455(2009)03-0306-06
Abstract:
Dynamic mechanical behaviors of 5A06 Al alloy by three kinds of processes and heat treatments were studied with the split Hopkinson pressure bar (SHPB) and static material test system over a wide range of strain rates and temperature. The Johnson-Cook constitutive relationship parameters were determined through these experiments. The strain-rate hardening term in the Johnson-Cook constitutive model was modified. The modified Johnson-Cook constitutive model is in agreement with the experimental data for 5A06 Al alloy.
Dynamic mechanical behaviors of 5A06 Al alloy by three kinds of processes and heat treatments were studied with the split Hopkinson pressure bar (SHPB) and static material test system over a wide range of strain rates and temperature. The Johnson-Cook constitutive relationship parameters were determined through these experiments. The strain-rate hardening term in the Johnson-Cook constitutive model was modified. The modified Johnson-Cook constitutive model is in agreement with the experimental data for 5A06 Al alloy.
2009, 29(3): 312-317.
doi: 10.11883/1001-1455(2009)03-0312-06
Abstract:
The mechanics models were established for arches with flexible supports at their ends. The flexible supports include vertical elastic and damping supports, horizontal elastic supports, and rotatable elastic supports. Based on the large deformation dynamic differential equations and finite difference method, the dynamic responses of arches subjected to explosive loading were explored, and the effects of flexible supports on explosion resistant capabilities were analyzed. The analysis shows that flexible supports have great effects on explosion resistant capabilities of arches, and different supports have distinctly different influences. Vertical elastic supports can decrease the peak internal forces of arches under explosive loading, postpone the appearance times of the peak internal forces, and improve the bearing capabilities of arches to explosive or transient loading. But horizontal elastic supports can increase the peak internal forces and relative displacements of arches, and weaken the bearing capabilities of arches.
The mechanics models were established for arches with flexible supports at their ends. The flexible supports include vertical elastic and damping supports, horizontal elastic supports, and rotatable elastic supports. Based on the large deformation dynamic differential equations and finite difference method, the dynamic responses of arches subjected to explosive loading were explored, and the effects of flexible supports on explosion resistant capabilities were analyzed. The analysis shows that flexible supports have great effects on explosion resistant capabilities of arches, and different supports have distinctly different influences. Vertical elastic supports can decrease the peak internal forces of arches under explosive loading, postpone the appearance times of the peak internal forces, and improve the bearing capabilities of arches to explosive or transient loading. But horizontal elastic supports can increase the peak internal forces and relative displacements of arches, and weaken the bearing capabilities of arches.
2009, 29(3): 318-321.
doi: 10.11883/1001-1455(2009)03-0318-05
Abstract:
An experimental sub-caliber technique of 7.62 mm rifle bullet launched by a 25 mm artillery is introduced in the present paper. A bakelite sabot is employed to fit the larger diameter of artillery for firing a smaller bullet. In order to ensure a bullet impacts in good appearance, a bakelite cylinder is stick to the rear bottom of the bullet to move its centroid forward. Two impediment plates are mounted before the target plate to separate the sabot and stop the sabot fragments, respectively.
An experimental sub-caliber technique of 7.62 mm rifle bullet launched by a 25 mm artillery is introduced in the present paper. A bakelite sabot is employed to fit the larger diameter of artillery for firing a smaller bullet. In order to ensure a bullet impacts in good appearance, a bakelite cylinder is stick to the rear bottom of the bullet to move its centroid forward. Two impediment plates are mounted before the target plate to separate the sabot and stop the sabot fragments, respectively.
2009, 29(3): 323-327.
doi: 10.11883/1001-1455(2009)03-0323-05
Abstract:
A sweep Langmuir probe diagnostic system was designed to investigate the electron temperature evolution of plasma produced by hypervelocity impact of LY12 aluminum projectiles into LY12 aluminum targets. In the experiment, LY12 aluminum spherical projectiles were loaded by a two-stage light-gas gun, the incident angle of LY12 aluminum projectiles was 30 and the impact velocities were different. The relation between the electron temperature of plasma and the impact velocity for the whole physical process was obtained by treating the effective data, which at the given probe positions were measured by the designed diagnostic systems.
A sweep Langmuir probe diagnostic system was designed to investigate the electron temperature evolution of plasma produced by hypervelocity impact of LY12 aluminum projectiles into LY12 aluminum targets. In the experiment, LY12 aluminum spherical projectiles were loaded by a two-stage light-gas gun, the incident angle of LY12 aluminum projectiles was 30 and the impact velocities were different. The relation between the electron temperature of plasma and the impact velocity for the whole physical process was obtained by treating the effective data, which at the given probe positions were measured by the designed diagnostic systems.
2009, 29(3): 328-332.
doi: 10.11883/1001-1455(2009)03-0328-05
Abstract:
Based on the study on the forming mechanism of blasting-induced crack under blasting stress wave, by adopting the Mohr-Coulomb criterion and the maximum stress criterion, the influence of in-situ stress redistribution on the proportional radius of the blasting-induced cracking zone (PRBICZ) in deep-buried tunnel excavation was explored. Results indicate that the in-situ stress redistribution has great influence on the PRBICZ, and that the in-situ stress redistribution in the rock mass can decrease the radial PRBICZ. Under compression and shear failure, the PRBICZ can be decreased more than 20%; under tension failure, the PRBICZ can be decreased more than 10%. Compression and shear failure of the rock mass is more likely to occur along the soft structure plane under blasting stress wave. The in-situ stress redistribution can reduce the blasting-induced cracking zone.
Based on the study on the forming mechanism of blasting-induced crack under blasting stress wave, by adopting the Mohr-Coulomb criterion and the maximum stress criterion, the influence of in-situ stress redistribution on the proportional radius of the blasting-induced cracking zone (PRBICZ) in deep-buried tunnel excavation was explored. Results indicate that the in-situ stress redistribution has great influence on the PRBICZ, and that the in-situ stress redistribution in the rock mass can decrease the radial PRBICZ. Under compression and shear failure, the PRBICZ can be decreased more than 20%; under tension failure, the PRBICZ can be decreased more than 10%. Compression and shear failure of the rock mass is more likely to occur along the soft structure plane under blasting stress wave. The in-situ stress redistribution can reduce the blasting-induced cracking zone.
2009, 29(3): 333-336.
doi: 10.11883/1001-1455(2009)03-0333-04
Abstract:
The explosive characters of ClO2 gas were investigated in a cylindrical explosion chamber of 20 liters capacity. Experimental results indicate that the lowest volume fraction of ClO2 gas for its explosive decomposition is 9.5%, and the corresponding highest volume fraction is no existent. Under these experimental conditions, the explosion pressure of ClO2 gas increases with its increasing volume fraction, its maximum explosion overpressure is 0.64 MPa when its volume fraction is 90%, and its explosive decomposition pressure is relevant with its volume fraction gradient. The appearance time of the maximum explosion overpressure is advanced with the increasing volume fraction of ClO2. When the volume fraction of ClO2 is 10%, the maximum explosion overpressure appears at 2 195.00 ms.When the volume fraction of ClO2 is 70%, the maximum explosion overpressure appears at less than 10 ms. If the volume fraction of ClO2 continues to increase, the appearance time of the maximum explosion overpressure keeps at about 8 ms.
The explosive characters of ClO2 gas were investigated in a cylindrical explosion chamber of 20 liters capacity. Experimental results indicate that the lowest volume fraction of ClO2 gas for its explosive decomposition is 9.5%, and the corresponding highest volume fraction is no existent. Under these experimental conditions, the explosion pressure of ClO2 gas increases with its increasing volume fraction, its maximum explosion overpressure is 0.64 MPa when its volume fraction is 90%, and its explosive decomposition pressure is relevant with its volume fraction gradient. The appearance time of the maximum explosion overpressure is advanced with the increasing volume fraction of ClO2. When the volume fraction of ClO2 is 10%, the maximum explosion overpressure appears at 2 195.00 ms.When the volume fraction of ClO2 is 70%, the maximum explosion overpressure appears at less than 10 ms. If the volume fraction of ClO2 continues to increase, the appearance time of the maximum explosion overpressure keeps at about 8 ms.
