A method for determining an explosion suppression structure of an explosion-proof enclosure

Abstract

The present application relates to the field of explosion-proof enclosure, in particular to a kind of determination method of explosion-proof structure of explosion-proof enclosure, including research on explosion suppression structure, three-dimensional model is established to explosion-proof structure of explosion-proof enclosure and is carried out blasting simulation, explosion-proof structure of explosion-proof enclosure is verified by experiment.The present application uses the explosion experiment system of self-erected, the characteristics of the explosion of premixed gas in explosion-proof enclosure using metal wire as explosion suppression material are experimentally studied, the influence of mesh number and layer number of metal wire on the explosion characteristics of premixed gas in explosion-proof enclosure is studied by numerical simulation method, the change characteristics of explosion pressure of premixed gas explosion process in explosion-proof enclosure after placing metal wire are explored, and the explosion suppression effect of explosion-proof enclosure is quantitatively analyzed, so that each explosion characteristic parameter of premixed gas in explosion-proof enclosure is obviously reduced, and the time of obtaining maximum explosion pressure of premixed gas explosion in explosion-proof enclosure is extended, and the explosion suppression effect of explosion-proof enclosure is better due to the design of explosion suppression structure of explosion-proof enclosure.

Description

Technical Field

[0001] This invention relates to the field of explosion-proof enclosures, and in particular to a method for determining the explosion suppression structure of an explosion-proof enclosure. Background Technology

[0002] A "flameproof enclosure" is an enclosure that allows explosive gases—premixed gases—to enter and burn and explode within the enclosure, but prevents the explosion products from rupturing the enclosure or escaping through any channel to the outside and igniting the surrounding air mixture. Based on this explosion-proof principle, a flameproof enclosure must possess sufficient mechanical strength to withstand the explosion pressure generated during an internal explosion without severe deformation or damage. The gaps between the components of the flameproof enclosure, i.e., the various channels from the inside to the outside, must have appropriate mechanical dimensions to reduce the energy carried by the explosion products escaping from the enclosure, or even prevent them from escaping altogether. This prevents the ignition of the air mixture surrounding the equipment.

[0003] Chinese Patent Publication No. CN110829685A discloses a high-sealing explosion-proof motor housing, relating to the field of motor technology. The invention includes a housing and bolts. Four mounting plates are fixedly connected to the periphery of the housing in a fan shape. A front end cover and an inner end cover are fixedly installed on both sides of the housing, respectively. An annular plate and an ear plate are fixedly connected to one side of the front end cover. Annular grooves are formed on both ends of the housing, and grooves are formed on both ends of the mounting plates. Two through slots are formed on the upper surface of the mounting plates corresponding to the positions of the grooves, and a disassembly plate is slidably fitted inside the through slots.

[0004] It is evident that the types of electrical components housed within explosion-proof enclosures are complex, resulting in a wide range of functions for these enclosures. Explosion-proof enclosures used in industrial settings are often characterized by complex electrical functions, large numbers, and dispersed installations. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a method for determining the explosion suppression structure of an explosion-proof enclosure, which has the advantages of achieving both safety and lightweight design of the explosion-proof enclosure.

[0006] To achieve the above objectives, the present invention provides a method for determining the explosion suppression structure of an explosion-proof enclosure, comprising:

[0007] Step S1: Study the explosion suppression structure and preliminarily determine the selected explosion suppression material and explosion-proof enclosure explosion suppression structure.

[0008] Step S2: Establish a three-dimensional model of the explosion-proof enclosure explosion suppression structure in step S1 and conduct an explosion simulation to preliminarily determine the number of metal wire mesh layers and mesh count.

[0009] Step S3: Conduct experimental verification of the explosion-proof enclosure explosion suppression structure determined in steps S1 and S2 to determine the accuracy of steps S1 and S2.

[0010] Furthermore, in step S1, the explosion suppression material is selected as stainless steel wire mesh, and the explosion suppression structure of the explosion-proof shell is an explosion suppression component made of stainless steel wire mesh, with the cross-sectional dimensions of the explosion suppression component being the same as those of the explosion-proof shell.

[0011] Furthermore, in step S2, a physical model of the explosion-proof enclosure with a 1:1 scale to the physical object is established using software. The established physical model is divided into polyhedral meshes, and the mesh independence is evaluated by repeated simulations with different numbers of meshes.

[0012] Furthermore, in step S2, when performing explosion simulation on the physical model of the explosion-proof enclosure to determine the mesh count of the metal wire mesh, the explosion simulation is performed on metal wire meshes with different mesh counts by fixing the number of metal wire mesh layers, and the explosion pressure curves of the explosion-proof enclosure under different metal wire mesh counts are compared and analyzed, and relevant parameters of the explosion characteristics when the metal wire mesh count is different are obtained.

[0013] Furthermore, by fixing the number of wire mesh layers and changing the wire mesh count to conduct different blasting simulations, the explosion characteristics and related parameters under different wire mesh counts were compared and analyzed to determine the optimal wire mesh count when the number of wire mesh layers was fixed.

[0014] Furthermore, the explosion characteristic-related parameters include the maximum explosion pressure value, the maximum explosion pressure rise rate, and the maximum explosion index.

[0015] Furthermore, in step S2, when performing explosion simulation on the physical model of the explosion-proof enclosure to determine the number of metal wire mesh layers, the optimal metal wire mesh count is fixed, and explosion simulation is performed on metal wire meshes with different numbers of layers. The explosion pressure curves of the explosion-proof enclosure under different numbers of metal wire mesh layers are compared and analyzed, and relevant parameters of explosion characteristics when the number of metal wire mesh layers is different are obtained.

[0016] Furthermore, by fixing the optimal mesh count of the metal wire mesh and changing the number of metal wire mesh layers to conduct different blasting simulations, the explosion characteristics and related parameters under blasting simulations with different metal wire mesh layer counts are compared and analyzed to determine the optimal number of metal wire mesh layers when the optimal mesh count of the metal wire mesh is fixed.

[0017] Furthermore, by changing the number of metal wire mesh layers and the mesh count of the metal wire mesh to conduct different explosion simulations, the explosion pressure curves of the explosion-proof shell under different metal wire mesh layers and mesh counts are compared and analyzed. The maximum explosion pressure value, maximum explosion pressure rise rate and maximum explosion index in each explosion simulation are compared to determine the optimal number of metal wire mesh layers and mesh count.

[0018] Furthermore, in step S3,

[0019] Step S31: Select the optimal number of metal wire mesh layers and mesh count to prepare an explosion suppression component made of stainless steel metal wire mesh;

[0020] Step S32: Set up an explosion test scheme for the empty shell, and set up three test sample schemes with different distances between the ignition source and the explosion suppression component, so as to provide a scheme for experimental verification of the explosion suppression effect of the explosion-proof shell explosion suppression structure.

[0021] Step S33: By setting the pressure sensor on the side of the explosion-proof enclosure, arranging the air inlet and outlet diagonally on the left and right side panels of the explosion-proof enclosure, and setting the ignition source on the front panel of the explosion-proof enclosure, an experimental setup is made to verify the explosion suppression effect of the explosion-proof enclosure explosion suppression structure.

[0022] Step S34: Perform explosion simulation on the empty shell explosion test scheme and the three test sample schemes in step S32, and experimentally verify the explosion suppression effect of the explosion-proof shell explosion suppression structure.

[0023] Compared with existing technologies, the beneficial effect of this invention lies in the development of an effective explosion-proof enclosure suppression structure. Using a self-built explosion experiment system, the characteristics of metal wire mesh as an explosion-suppressing material in suppressing the explosion of ethylene / air premixed gas inside the explosion-proof enclosure were experimentally studied. The changes in explosion pressure during the ethylene / air premixed gas explosion process inside the explosion-proof enclosure after the placement of metal wire mesh were explored, and the explosion-suppressing effect of the explosion-proof enclosure was quantitatively analyzed. The main conclusions are as follows:

[0024] (1) Metal wire mesh, as an explosion suppression material, can effectively suppress the explosion of ethylene / air premixed gas inside the explosion-proof enclosure.

[0025] (2) After placing a metal wire mesh inside the explosion-proof enclosure, the maximum explosion pressure generated by the explosion is coupled with the heat absorption of the metal wire mesh itself and the turbulence it causes.

[0026] (3) When an explosion suppression structure component is installed inside the explosion-proof enclosure, the explosion characteristic parameters such as the maximum explosion pressure, the maximum explosion pressure rise rate, and the maximum explosion index of the ethylene / air premixed gas inside the explosion-proof enclosure, as measured in the experiment, are significantly lower than those when no explosion suppression structure component is installed.

[0027] (4) An explosion suppression structure component is installed inside the explosion-proof enclosure, which prolongs the time it takes for the ethylene / air premixed gas inside the explosion-proof enclosure to reach the maximum explosion pressure.

[0028] (5) The closer the explosion suppression component is to the ignition source, the better the explosion suppression effect of the explosion-proof enclosure and the higher the weight reduction rate of the explosion-proof enclosure.

[0029] In particular, by studying an effective explosion-proof enclosure structure, and using a self-built explosion test system, the characteristics of metal wire mesh as an explosion-proof material in suppressing the explosion of ethylene and air premixed gas inside the explosion-proof enclosure were experimentally studied. The characteristics of the explosion pressure change during the explosion process of ethylene and air premixed gas inside the explosion-proof enclosure after the metal wire mesh was placed were explored. The relevant parameters of the explosion characteristics under different numbers of metal wire mesh layers and mesh counts were obtained, compared and analyzed, and the optimal number of metal wire mesh layers and mesh count were determined. Explosion simulation was carried out to quantitatively analyze the explosion-proof enclosure's explosion-proof effect.

[0030] In particular, by using explosion-suppressing components made of stainless steel wire mesh, and setting the cross-sectional dimensions of the explosion-suppressing components to be the same as those of the explosion-proof enclosure, the safety and lightweight of the explosion-proof enclosure can be achieved because stainless steel wire mesh has the advantages of small size, low price, light weight, good hardening performance, and no impact on electrical performance.

[0031] In particular, by using polyhedral meshes to mesh the physical model of the explosion-proof enclosure, the meshing efficiency is improved, and the manual operation of polyhedral meshing is reduced, which can significantly improve the efficiency of meshing and reduce unnecessary resource waste.

[0032] Furthermore, by changing the number of wire mesh layers and the mesh count, different blast simulations were conducted on the three-dimensional model of the explosion-proof enclosure's explosion suppression structure. The explosion pressure curves of the explosion-proof enclosure under different wire mesh layers and mesh counts were compared and analyzed, and relevant parameters of the explosion characteristics under different wire mesh layers and mesh counts were obtained. By repeatedly changing the number of wire mesh layers and mesh counts to conduct blast simulations, the accuracy of the experiment was improved, errors were reduced, and the experimental results were made more accurate.

[0033] Furthermore, by comparing and analyzing the temperature field and turbulent flow field distribution diagrams of the central cross section of the explosion-proof enclosure before and after the flame passes through the metal wire mesh according to different mesh counts, it was found that during the flame propagation process, the metal wire mesh, as an obstacle, enhances the turbulent kinetic energy of the premixed gas inside the explosion-proof enclosure, increases the intensity of flame turbulence, makes the combustion reaction more intense, and generates greater pressure from the explosion, thus reaching the maximum explosion pressure earlier. Therefore, the flame quenching effect is better with the increase of the metal wire mesh mesh count, verifying that the metal wire mesh has good quenching performance.

[0034] In particular, further, through five experiments on the aforementioned empty shell explosion experiment and three experimental sample schemes, it was found that when the explosion suppression component is placed inside the explosion-proof enclosure, the combustion of ethylene and air premixed gas inside the explosion-proof enclosure is less severe than when there is no explosion suppression component. The explosion suppression component can be considered an obstacle to flame propagation. When the flame passes through the obstacle, the flame turbulence intensity increases, the combustion reaction becomes more intense, the premixed gas inside the explosion-proof enclosure burns rapidly, and the flame propagation speed accelerates. Compared to the wave absorption and heat dissipation effects of the explosion suppression component itself, these factors are not dominant. Therefore, after placing the explosion suppression component, the maximum explosion value of the explosion-proof enclosure is significantly reduced compared to when no explosion suppression component is placed. Furthermore, the closer the explosion suppression component is to the ignition source, the lower the explosion value. The downward trend is also obvious; the maximum explosion rise slope and maximum explosion index of the explosion-proof enclosure also decrease accordingly; the time for the explosion-proof enclosure to obtain the maximum explosion pressure under the three experimental sample schemes is opposite to the change law of the maximum explosion pressure, the maximum explosion rise slope and the maximum explosion index. The closer the explosion suppression component is to the ignition source, the longer the time for the maximum explosion pressure to rise. Since the excitation effect of the explosion suppression component on the intensity of flame turbulence is inferior to the wave absorption and heat dissipation effect of the metal wire mesh material itself, the closer the ignition source is to the explosion suppression component, the more obvious the effect of the metal wire mesh. Therefore, after placing the explosion suppression component, the time for the explosion-proof enclosure to obtain the maximum explosion pressure is also longer than that under the condition of not placing the explosion suppression component. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating the method for determining the explosion suppression structure of an explosion-proof enclosure;

[0036] Figure 2 This is a graph showing the explosion pressure curves of explosion-proof enclosures with different metal wire mesh counts;

[0037] Figure 3 It is a temperature field distribution diagram;

[0038] Figure 4 middle

[0039] (a) and (b) are the temperature field cloud map and turbulent kinetic energy distribution cloud map inside the explosion-proof enclosure under the condition of mesh number 5.

[0040] (c) and (d) are the temperature field cloud map and turbulent kinetic energy distribution cloud map inside the explosion-proof enclosure under the working condition of mesh number 10;

[0041] Figure 5 This is a graph showing the change of explosion pressure inside the explosion-proof enclosure with different explosion suppression structures over time.

[0042] Figure 6 middle

[0043] (a) is the explosion pressure diagram.

[0044] (b) is the slope of the maximum explosion pressure rise.

[0045] (c) is the maximum explosion index diagram.

[0046] (d) is the maximum explosion pressure rise time diagram. Detailed Implementation

[0047] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0048] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0049] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0050] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] Please see Figures 1-6 As shown, Figure 1 This is a flowchart illustrating the method for determining the explosion suppression structure of an explosion-proof enclosure; Figure 2 This is a graph showing the explosion pressure curves of explosion-proof enclosures with different metal wire mesh counts; Figure 3 It is a temperature field distribution diagram; Figure 4 (a) and (b) are the temperature field cloud maps and turbulent kinetic energy distribution cloud maps inside the explosion-proof enclosure under the condition of 5 mesh size; (c) and (d) are the temperature field cloud maps and turbulent kinetic energy distribution cloud maps inside the explosion-proof enclosure under the condition of 10 mesh size. Figure 5 This is a graph showing the change of explosion pressure inside the explosion-proof enclosure with different explosion suppression structures over time. Figure 6 (a) is the explosion pressure diagram, (b) is the maximum explosion pressure rise slope diagram, (c) is the maximum explosion index diagram, and (d) is the maximum explosion pressure rise time diagram.

[0052] This invention provides a method for determining the explosion suppression structure of an explosion-proof enclosure, comprising:

[0053] Step S1: Study the explosion suppression structure and preliminarily determine the selected explosion suppression material and explosion-proof enclosure explosion suppression structure.

[0054] Step S2: Establish a three-dimensional model of the explosion-proof enclosure explosion suppression structure in step S1 and conduct an explosion simulation to preliminarily determine the number of metal wire mesh layers and mesh count.

[0055] Step S3: Conduct experimental verification of the explosion-proof enclosure explosion suppression structure determined in steps S1 and S2 to determine the accuracy of steps S1 and S2.

[0056] Specifically, in the explosion simulation, the explosion gas inside the explosion-proof enclosure is set as a premixed gas of ethylene and air, wherein the ethylene concentration is 8±0.5%.

[0057] This study investigated an effective explosion-suppressing structure for explosion-proof enclosures. Using a self-built explosion test system, the characteristics of metal wire mesh as an explosion-suppressing material in suppressing the explosion of ethylene and air premixed gas inside the explosion-proof enclosure were experimentally studied. The changes in explosion pressure during the explosion process of ethylene and air premixed gas inside the explosion-proof enclosure after the placement of metal wire mesh were explored. Explosion characteristic parameters under different numbers of metal wire mesh layers and mesh counts were obtained, compared and analyzed, and the optimal number of metal wire mesh layers and mesh count were determined. Explosion simulation was conducted to quantitatively analyze the explosion-suppressing effect of the explosion-proof enclosure.

[0058] Specifically, in step S1, the explosion suppression material is selected as stainless steel wire mesh, and the explosion suppression structure of the explosion-proof shell is an explosion suppression component made of stainless steel wire mesh. The cross-sectional dimensions of the explosion suppression component are set to be the same as those of the explosion-proof shell to avoid pressure overlap of the explosion-proof shell after the explosion suppression component is placed.

[0059] By employing explosion-suppressing components made of stainless steel wire mesh, and setting the cross-sectional dimensions of the explosion-suppressing components to be the same as those of the explosion-proof enclosure, the safety and lightweight of the explosion-proof enclosure can be achieved due to the advantages of stainless steel wire mesh, such as small size, low price, light weight, good hardening performance, and no impact on electrical performance.

[0060] Specifically, in step S2, a physical model of the explosion-proof enclosure with a 1:1 scale to the physical object is established using software. The established physical model is divided using a polyhedral mesh. The mesh independence is evaluated by repeated simulations with different mesh numbers. After the mesh independence is verified, the mesh number is determined to be 507996.

[0061] By using polyhedral meshes to mesh the physical model of the explosion-proof enclosure, the meshing efficiency is improved, and the manual operation of polyhedral meshing is reduced, which can significantly improve the efficiency of meshing and reduce unnecessary resource waste.

[0062] Specifically, the number of metal wire mesh layers is set to i, i = 1, 10, 20, and the number of metal wire mesh meshes is set to j, j = 5, 8, 10. Explosion simulations are performed on the physical model of the explosion-proof enclosure based on different numbers of metal wire mesh layers i and different numbers of metal wire mesh meshes j. The explosion pressure curves of the explosion-proof enclosure under different numbers of metal wire mesh layers i and different numbers of metal wire mesh meshes j are compared and analyzed, and relevant parameters of explosion characteristics under different numbers of metal wire mesh layers i and different numbers of metal wire mesh meshes j are obtained. Among them, the relevant parameters of explosion characteristics include the maximum explosion pressure value, the maximum explosion pressure rise rate, and the maximum explosion index.

[0063] By changing the number of wire mesh layers and the mesh count, different blast simulations were conducted on the three-dimensional model of the explosion-proof enclosure's explosion suppression structure. The explosion pressure curves of the explosion-proof enclosure under different wire mesh layers and mesh counts were compared and analyzed. The relevant parameters of the explosion characteristics under different wire mesh layers and mesh counts were obtained. By repeatedly changing the number of wire mesh layers and mesh counts to conduct blast simulations, the accuracy of the experiment was improved, errors were reduced, and the experimental results were made more accurate.

[0064] Specifically, when performing explosion simulations on the physical model of the explosion-proof enclosure to determine the mesh count, the number of metal mesh layers was set to a fixed value i = 1, and the mesh count j was changed to 5, 8, and 10 for different explosion simulations. The explosion pressure curves of the explosion-proof enclosure under different mesh count j were compared and analyzed. The explosion characteristic parameters obtained under different mesh count j were compared. When the mesh count j was 5, 8, and 10, the maximum explosion pressure of the explosion-proof enclosure obtained by numerical simulation was 586 kPa, 580 kPa, and 559 kPa, respectively. The above data are referenced in Table 1 below, indicating that the explosion pressure generated by the explosion of the premixed gas inside the explosion-proof enclosure was suppressed. As the mesh count j increased, the time for the explosion-proof enclosure to reach the maximum explosion pressure increased, the rate of increase of the maximum explosion pressure decreased, and the maximum explosion index also decreased. The optimal mesh count j was determined when the number of metal mesh layers i = 1, and the optimal mesh count was j = 10.

[0065] Table 1. Parameters related to the explosion characteristics of metal wire mesh with different mesh counts.

[0066]

[0067]

[0068] By fixing the number of metal wire mesh layers at i=1 and changing the mesh count j=5, 8, and 10, three explosion simulations were conducted. It can be seen that as the mesh count j increases, the maximum explosion pressure inside the explosion-proof enclosure decreases. This indicates that the larger the mesh count, the better the explosion pressure generated by the explosion of ethylene and air premixed gas inside the explosion-proof enclosure can be controlled. Therefore, the optimal mesh count j=10 was determined, which significantly improves the explosion suppression effect of the explosion-proof enclosure.

[0069] Specifically, in step S2, when performing explosion simulation on the physical model of the explosion-proof enclosure to determine the number of metal wire mesh layers, the optimal metal wire mesh number j = 10 is set, and the number of metal wire mesh layers i = 1, 10, 20 is changed. Explosion simulations are performed on metal wire meshes with different numbers of layers, and the explosion pressure curves of the explosion-proof enclosure under explosion simulations with different metal wire mesh layer numbers i are compared and analyzed. The explosion characteristic parameters obtained under explosion simulations with different metal wire mesh layer numbers i are compared. When the number of metal wire mesh layers i is 1, 10, and 20, the explosion pressure curves of the explosion-proof enclosure obtained by numerical simulation are... The maximum explosion pressures of the explosion-proof enclosure are 560 kPa, 506 kPa, and 150 kPa, respectively. The above data are referenced in Table 2 below, which shows that the metal wire mesh has an effective suppression effect on the maximum explosion pressure of the premixed gas explosion inside the explosion-proof enclosure. As the number of metal wire mesh layers i increases, the time for the explosion-proof enclosure to reach the maximum explosion pressure is earlier, the rate of increase of the maximum explosion pressure shows an upward trend, and the maximum explosion index also increases accordingly. The optimal number of metal wire mesh layers i is determined when the optimal metal wire mesh number j = 10. The optimal number of metal wire mesh layers is i = 20.

[0070] Table 2. Parameters related to explosion characteristics when the number of metal wire mesh layers is different.

[0071]

[0072] By fixing the optimal wire mesh count j=10 and changing the number of wire mesh layers i=1, 10, 20, three explosion simulations were conducted. It can be seen that as the number of wire mesh layers i increases, the maximum explosion pressure inside the explosion-proof enclosure decreases. This indicates that the larger the number of wire mesh layers, the better the explosion pressure generated by the explosion of ethylene and air premixed gas inside the explosion-proof enclosure can be controlled. Therefore, the optimal number of wire mesh layers i=20 was determined, which significantly improves the explosion suppression effect of the explosion-proof enclosure.

[0073] Specifically, when the mesh count j = 5 and j = 10 of the metal wire mesh were set, the temperature field and turbulent flow field distribution diagrams of the central cross section of the explosion-proof shell before and after the flame passed through the metal wire mesh were compared and analyzed. When the mesh count was 5 and 10, the temperature of the flame after passing through the metal wire mesh decreased to 669.22℃ and 471.40℃, respectively, and the maximum turbulence intensity inside the explosion-proof shell was 6.96 m2 / s2 and 10.04 m2 / s2, respectively. It can be seen that as the mesh count j of the metal wire mesh increases, the turbulence intensity also increases. The larger the mesh count j of the metal wire mesh, the smaller the internal pores, the more contact the flame has with the metal wire mesh, the greater the drop in explosion pressure, and the longer it takes for the explosion-proof shell to reach the maximum explosion pressure. The heat absorption and wave absorption effects of the metal wire mesh play a dominant role, and the maximum explosion pressure value generated by the explosion is coupled with the heat absorption of the metal wire mesh itself and the turbulence it causes.

[0074] By comparing and analyzing the temperature field and turbulent flow field distribution diagrams of the central cross section of the explosion-proof enclosure before and after the flame passes through the metal wire mesh according to different mesh counts j, it was found that during the flame propagation process, the metal wire mesh, as an obstacle, enhances the turbulent kinetic energy of the premixed gas inside the explosion-proof enclosure, increases the intensity of flame turbulence, makes the combustion reaction more intense, and generates greater pressure from the explosion. The time to reach the maximum explosion pressure is also earlier. Therefore, the flame quenching effect is better with the increase of the metal wire mesh mesh count, verifying that the metal wire mesh has good quenching performance.

[0075] Specifically, in step S3,

[0076] Step S31: Select the optimal number of metal wire mesh layers i = 20 and the optimal number of metal wire mesh j = 10. Cut the single layer of metal wire mesh to a size of 460mm × 305mm × 190mm. Then, use a die-casting machine to die-cast the 20 layers of metal wire mesh into one piece. The die-cast metal wire mesh is fixed around the perimeter with steel clamps. Use the die-casting machine to press the clamps and metal wire mesh together to assemble the explosion suppression component.

[0077] Step S32: An explosion test scheme for the explosion-proof enclosure is set up. Three test sample schemes are established by changing the distance X between the explosion suppression component and the ignition source (X = 150mm, 100mm, 50mm) to fully evaluate the explosion suppression effect of the explosion-proof enclosure structure. These include Test Sample Scheme 1, Test Sample Scheme 2, and Test Sample Scheme 3.

[0078] Experimental sample scheme one, the experimental sample scheme when the explosion suppression component is at a distance of X = 150 mm from the ignition source.

[0079] Experimental sample scheme two, the experimental sample scheme when the explosion suppression component is at a distance of X = 100 mm from the ignition source.

[0080] Experimental sample scheme three: the experimental sample scheme when the explosion suppression component is at a distance of X = 50 mm from the ignition source;

[0081] Step S33: By setting the pressure sensor on the side of the explosion-proof enclosure, arranging the air inlet and outlet diagonally on the left and right side panels of the explosion-proof enclosure, and setting the ignition source on the front panel of the explosion-proof enclosure, an experimental setup is made to verify the explosion suppression effect of the explosion-proof enclosure explosion suppression structure.

[0082] Step S34: Perform explosion simulation on the empty shell explosion test scheme and the three test sample schemes in step S32, and experimentally verify the explosion suppression effect of the explosion-proof shell explosion suppression structure.

[0083] Specifically, an empty shell explosion experiment was set up and conducted with the three experimental sample schemes under normal temperature and pressure conditions, with an atmospheric pressure of about 101.325 kPa, an ambient humidity of no more than 40%, and an ambient temperature of about 20°C. The empty shell explosion experiment scheme and the three experimental sample schemes were all conducted 5 times.

[0084] Specifically, in the empty shell explosion test scheme, the maximum explosion pressure rise time measured after 5 experiments was 25.36 ms, and the maximum explosion pressure value was 624.58 kPa. The maximum explosion pressure rise time and the maximum explosion pressure value are used as the benchmark data for the empty shell explosion test. The above data are referred to in Table 3 below.

[0085] Table 3. Maximum explosion pressure rise time and maximum explosion pressure in the empty shell explosion experiment.

[0086]

[0087] Specifically, in the first experimental sample scheme, the maximum explosion pressure rise time measured after 5 experiments was 29.89 ms, and the maximum explosion pressure value was 423.61 kPa. The maximum explosion pressure rise time and the maximum explosion pressure value are used as comparative data for the first experimental sample scheme. The above data are referred to in Table 4 below.

[0088] Table 4. Maximum explosion pressure rise time and maximum explosion pressure for experimental sample scheme 1.

[0089]

[0090] Specifically, in the second experimental sample, the maximum explosion pressure rise time measured after 5 experiments was 28.45 ms, and the maximum explosion pressure value was 462.61 kPa. The maximum explosion pressure rise time and the maximum explosion pressure value are used as comparative data for the second experimental sample. The above data are referred to in Table 5 below.

[0091] Table 5. Maximum explosion pressure rise time and maximum explosion pressure for experimental sample scheme 2.

[0092]

[0093]

[0094] Specifically, in the experimental sample scheme three, the maximum explosion pressure rise time measured after 5 experiments was 27.51 ms, and the maximum explosion pressure value was 582.51 kPa. The maximum explosion pressure rise time and the maximum explosion pressure value are used as comparative data for experimental sample scheme three. The above data are referred to in Table 6 below.

[0095] Table 6. Maximum explosion pressure rise time and maximum explosion pressure for experimental sample scheme 3.

[0096]

[0097] Specifically, by conducting five experiments on the empty shell explosion test and the three experimental sample schemes, the maximum explosion pressure rise time and maximum explosion pressure were obtained under different experimental schemes and at different times. It was found that when the maximum explosion pressure value measured inside the explosion-proof shell under the three experimental sample schemes was lower than that inside the empty shell, the explosion pressure rise slope also decreased as the distance between the explosion suppression component and the ignition source decreased. After the explosion pressure value of the explosion-proof shell reached its peak, the explosion pressure value dropped rapidly and finally dropped to atmospheric pressure, indicating that the explosion pressure inside the explosion-proof shell was effectively suppressed.

[0098] Five experiments were conducted on the empty enclosure explosion test and three experimental sample schemes. Based on the observation that the explosion suppression component was placed inside the explosion-proof enclosure, the combustion of ethylene and air premixed gas inside the enclosure, compared to the case without the explosion suppression component, shows that the explosion suppression component acts as an obstacle to flame propagation. When the flame passes through the obstacle, the flame turbulence intensity increases, the combustion reaction becomes more intense, the premixed gas inside the explosion-proof enclosure burns rapidly, and the flame propagation speed accelerates. The absorption and heat dissipation effects of the explosion suppression component itself are not the dominant factor. Therefore, after placing the explosion suppression component, the maximum explosion value of the explosion-proof enclosure is significantly reduced compared to the case without it, and the closer the explosion suppression component is to the ignition source, the greater the downward trend. It is evident that the maximum explosion rise slope and maximum explosion index of the explosion-proof enclosure also decrease accordingly. Under the three experimental sample schemes, the time for the explosion-proof enclosure to obtain the maximum explosion pressure is opposite to the change law of the maximum explosion pressure, the maximum explosion rise slope, and the maximum explosion index. The closer the explosion suppression component is to the ignition source, the longer the time for the maximum explosion pressure to rise. Since the excitation effect of the explosion suppression component on the intensity of flame turbulence is inferior to the wave absorption and heat dissipation effect of the metal wire mesh material itself, the closer the ignition source is to the explosion suppression component, the more obvious the effect of the metal wire mesh. Therefore, after placing the explosion suppression component, the time for the explosion-proof enclosure to obtain the maximum explosion pressure is also longer than that under the condition of not placing the explosion suppression component.

[0099] Specifically, the explosion suppression effect of the explosion suppression component on the ethylene and air premixed gas inside the explosion-proof enclosure is measured by the maximum explosion pressure attenuation rate. An evaluation was conducted on the maximum explosion pressure decay rate.

[0100]

[0101] Where: Pmax(0) is the maximum explosion pressure generated by the explosion-proof enclosure without the metal wire mesh explosion suppression component; Pmax(w) is the maximum explosion pressure generated by the explosion-proof enclosure after the metal wire mesh explosion suppression component is installed.

[0102] Specifically, the maximum explosion pressure decay rate The baseline data selected from the empty shell explosion test scheme and the three test sample schemes, as well as the comparative data under the three schemes, were used as the explosion suppression effect evaluation data.

[0103] Specifically, as the distance between the explosion suppression component and the ignition source decreases, the maximum explosion pressure attenuation rate of the explosion-proof enclosure continuously increases. When the distance between the explosion suppression component and the ignition source is 50mm, the maximum explosion pressure attenuation rate of the explosion-proof enclosure is the largest, at 32.18%. The above data are referenced in Table 7 below.

[0104] Table 7. Maximum Explosion Pressure Decay Rate Data

[0105]

[0106] Specifically, the explosion-proof enclosure's wall thickness is theoretically calculated according to the explosion-proof enclosure wall thickness calculation formula, serving as the theoretical basis for the design of the explosion-proof enclosure. The explosion-proof enclosure wall thickness δ...

[0107]

[0108] Where σ is the calculated thickness of the planar thin plate; b is the length of the short side of the rectangular thin plate; k is the safety factor, k = 1.5; p is the design pressure, which is 1500 kPa for Class IIB explosion-proof enclosures; C is the stress coefficient; σT is the yield strength of the thin plate material, which is 240000 kPa for material Q235-A. The above data are referenced in Table 8 below.

[0109] Table 8 Stress Coefficient

[0110]

[0111]

[0112] This invention studies an effective explosion suppression structure for explosion-proof enclosures. Using a self-built explosion test system, the characteristics of metal wire mesh as an explosion suppression material in suppressing the explosion of premixed gas inside the explosion-proof enclosure were experimentally studied. The changes in explosion pressure during the explosion process of the premixed gas inside the explosion-proof enclosure after placing the metal wire mesh were explored, and the explosion suppression effect of the explosion-proof enclosure was quantitatively analyzed. The main conclusions are as follows:

[0113] (1) Metal wire mesh, as an explosion suppression material, can effectively suppress the explosion of premixed gas inside the explosion-proof enclosure.

[0114] (2) After placing a metal wire mesh inside the explosion-proof enclosure, the maximum explosion pressure generated by the explosion is coupled with the heat absorption of the metal wire mesh itself and the turbulence it causes.

[0115] (3) When the explosion-proof enclosure is equipped with an explosion-suppressing structure component, the explosion characteristic parameters such as the maximum explosion pressure, the maximum explosion pressure rise rate and the maximum explosion index of the premixed gas inside the explosion-proof enclosure are significantly reduced compared with those without the explosion-suppressing structure component.

[0116] (4) An explosion suppression structure component is installed inside the explosion-proof enclosure, which prolongs the time it takes for the premixed gas inside the explosion-proof enclosure to reach the maximum explosion pressure.

[0117] (5) The closer the explosion suppression component is to the ignition source, the better the explosion suppression effect of the explosion-proof enclosure and the higher the weight reduction rate of the explosion-proof enclosure.

[0118] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0119] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining the explosion suppression structure of an explosion-proof enclosure, characterized in that, include, Step S1: Study the explosion suppression structure and preliminarily determine the selected explosion suppression material and explosion-proof enclosure explosion suppression structure. Step S2: Establish a three-dimensional model of the explosion-proof enclosure explosion suppression structure in step S1 and conduct an explosion simulation to preliminarily determine the number of metal wire mesh layers and mesh count. Step S3: Conduct experimental verification of the explosion-proof enclosure explosion suppression structure determined in steps S1 and S2 to determine the accuracy of steps S1 and S2. In step S1, the explosion suppression material is selected as stainless steel wire mesh, and the explosion suppression structure of the explosion-proof shell is an explosion suppression component made of stainless steel wire mesh. The cross-sectional dimensions of the explosion suppression component are set to be the same as those of the explosion-proof shell. In step S2, a physical model of the explosion-proof enclosure at a 1:1 scale with the physical object is established using software. The established physical model is divided into polyhedral meshes, and the mesh independence is evaluated by repeated simulations with different mesh numbers. When performing explosion simulations on the physical model of the explosion-proof enclosure to determine the mesh count of the metal wire mesh, the explosion simulations are performed on metal wire meshes with different mesh counts by fixing the number of metal wire mesh layers. The explosion pressure curves of the explosion-proof enclosure under different metal wire mesh counts are compared and analyzed, and relevant parameters of the explosion characteristics when the metal wire mesh count is different are obtained. When performing explosion simulation on the physical model of the explosion-proof enclosure to determine the number of metal wire mesh layers, the optimal metal wire mesh count is fixed, and explosion simulations are performed on metal wire meshes with different numbers of layers. The explosion pressure curves of the explosion-proof enclosure under different numbers of metal wire mesh layers are compared and analyzed, and relevant parameters of explosion characteristics when the number of metal wire mesh layers is different are obtained.

2. The method for determining the explosion-proof enclosure explosion-suppression structure according to claim 1, characterized in that, By fixing the number of wire mesh layers and changing the mesh count, different blasting simulations were conducted. The explosion characteristics parameters obtained under different wire mesh count blasting simulations were compared and analyzed to determine the optimal wire mesh count when the number of wire mesh layers was fixed.

3. The method for determining the explosion-proof enclosure explosion-suppression structure according to claim 2, characterized in that, The explosion characteristic related parameters, This includes the maximum explosion pressure value, the maximum explosion pressure rise rate, and the maximum explosion index.

4. The method for determining the explosion-proof enclosure explosion-suppression structure according to claim 1, characterized in that, By fixing the optimal mesh count of the metal wire mesh and changing the number of metal wire mesh layers to conduct different blasting simulations, the explosion characteristics and related parameters under different metal wire mesh layer numbers in the blasting simulations are compared and analyzed to determine the optimal number of metal wire mesh layers when the optimal mesh count is fixed.

5. The method for determining the explosion-proof enclosure explosion-suppression structure according to any one of claims 1-4, characterized in that, By changing the number of metal wire mesh layers and the mesh count, different blasting simulations are conducted. The explosion pressure curves of the explosion-proof enclosure under different metal wire mesh layers and mesh counts are compared and analyzed. The maximum explosion pressure value, maximum explosion pressure rise rate, and maximum explosion index in each blasting simulation are compared to determine the optimal number of metal wire mesh layers and mesh count.

6. The method for determining the explosion-proof enclosure explosion-suppression structure according to claim 5, characterized in that, In step S3, Step S31: Select the optimal number of metal wire mesh layers and mesh count to prepare an explosion suppression component made of stainless steel metal wire mesh; Step S32: Set up an explosion test scheme for the empty shell, and set up three test sample schemes with different distances between the ignition source and the explosion suppression component, so as to provide a scheme for experimental verification of the explosion suppression effect of the explosion-proof shell explosion suppression structure. Step S33: By setting the pressure sensor on the side of the explosion-proof enclosure, arranging the air inlet and outlet diagonally on the left and right side panels of the explosion-proof enclosure, and setting the ignition source on the front panel of the explosion-proof enclosure, an experimental setup is made to verify the explosion suppression effect of the explosion-proof enclosure explosion suppression structure. Step S34: Perform explosion simulation on the empty shell explosion test scheme and the three test sample schemes in step S32, and experimentally verify the explosion suppression effect of the explosion-proof shell explosion suppression structure.

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