CN110111860A - A kind of hexogen detonation analogy method - Google Patents

Abstract

The invention discloses a kind of hexogen detonation analogy methods, it is parallel to the electric field of carbon nanotube axis direction by applying in the hexogen composite model for having coupled carbon nanotube, RDX is reacted completely, and electric field strength is bigger, reaction speed is faster, and it is shorter that RDX fires the time.As a result, by adjusting the intensity of electric field, make the time of fire point generation with change, so as to accomplish the control to RDX reaction time (the detonation time).

Description

A RDX deflagration simulation method

technical field

The invention relates to the technical field of energetic material deflagration simulation experiments, in particular to a RDX deflagration simulation method.

Background technique

Cyclotrimethylene trinitramine, also known as RDX (abbreviated as RDX), is an important energetic material with a molecular formula of C ₃ H ₆ N ₆ O ₆ . Its decomposition will generate a large amount of energy in an instant. The convenience of theoretical simulation enables it to be studied from various aspects. In the research of this energetic material, the main research direction is to make the material release energy faster and reduce the explosion sensitivity. The previous research content mainly includes: additives such as Mg powder and AL powder, etc., to improve the heat release performance of the RDX burner, and to increase the energy release intensity of energetic materials.

In addition, applying an external electric field can increase the energy of the RDX explosion energy, and at the same time, the detonation velocity and detonation pressure are also enhanced. Looking back on related research, the theoretical research on the effect of external electric field is mainly the influence of electric field on the properties of energetic material molecules themselves, such as the bond length of each chemical bond, the hydrogen bond between energetic material molecules, and the first step decomposition process of energetic material molecules. influences. However, there are few detailed records on the decomposition process of energetic materials under electric field. This technology only increases the combustion performance, but cannot effectively control the detonation time of energetic materials. It only involves the action of the electric field, and there is no detailed information about the effect of the electric field on the reaction of energetic materials. In these studies, the minimum activation energy is mainly discussed, and often stops at the first step of decomposition, ignoring the subsequent complex process of molecular crystal decomposition of energetic materials.

Contents of the invention

Aiming at the deficiencies of the prior art, the object of the present invention is to provide a RDX deflagration simulation method to solve the existing problem that the RDX deflagration cannot be effectively controlled.

The technical scheme that the present invention solves the problems of the technologies described above is as follows:

A RDX deflagration simulation method, comprising:

(1) Establish a three-dimensional model of the RDX crystal unit cell, place the RDX crystal unit cell on the positive semi-axes of x, y, and z in the Cartesian coordinate system according to the arrangement structure of lattice constants a, b, and c , and then extend the RDX crystal unit cell model to a single crystal model;

(2) Remove the RDX molecules in the columnar region perpendicular to the yoz plane in the center of the single crystal model to form a cylindrical cavity, and then put in metal carbon nanotubes for coupling to obtain a composite model;

(3) Apply an electric field parallel to the axial direction of the metal-type carbon nanotube to the composite model, start timing from the time when the electric field is applied, and obtain the deflagration time of RDX according to the applied electric field strength.

Further, in a preferred embodiment of the present invention, step (2) also includes: using NPT thermodynamic ensemble to optimize the relaxation of the composite model, the specific process is:

Set the three-dimensional periodic boundary conditions of the composite model and the number of particles in the system, set the step size as 0.1 femtosecond and the relaxation time as 30ps; the volume and energy of the system change with time.

Further, in a preferred embodiment of the present invention, in step (3), the NVE thermodynamic ensemble is used to apply an electric field to the composite model; the time for deflagration of RDX is obtained according to the following formula according to the applied electric field strength:

U(t,E)＝U ₀ (E)+du×exp[-(tt _I )/τ(E)];

In the formula: U(t,E) is the total potential energy of the system, U ₀ (E) is the asymptotic potential energy of the product after stabilization, du is the exothermic energy of the reaction, t _I is the reaction start time, τ(E) is the black The time of Sorkin's complete decomposition; where U(t,E), U ₀ (E), du and τ(E) are tracked in the NVE thermodynamic ensemble.

Further, in a preferred embodiment of the present invention, in step (1), a three-dimensional model of the RDX crystal unit cell is established by using the NVT thermodynamic ensemble.

The present invention has the following beneficial effects:

In the present invention, by applying an electric field parallel to the axial direction of carbon nanotubes in the RDX composite model coupled with carbon nanotubes, RDX can be completely reacted, and the greater the electric field intensity, the faster the reaction speed and the shorter the RDX detonation time . Thus, by adjusting the intensity of the electric field, the time of ignition point can be changed accordingly, so as to control the RDX reaction time (deflagration time).

Description of drawings

Figure 1 is the structural diagram of the composite model of RDX with embedded CNT before the relaxation is optimized;

Figure 2 is a structural diagram of the composite model of RDX embedded with metal-type CNTs after optimized relaxation;

Fig. 3 is a structural diagram of the composite model of RDX embedded with semiconducting CNTs after optimized relaxation;

Fig. 4 is the structure schematic diagram of the relationship between the electric field application direction and the CNT tube axis;

Fig. 5 is a graph showing the evolution of the number of RDX (CNT) molecules with time under the action of different external electric fields.

Detailed ways

The principles and features of the present invention are described below in conjunction with the accompanying drawings, and the examples given are only used to explain the present invention, and are not intended to limit the scope of the present invention. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

RDX is a molecular crystal. There are 8 RDX molecules in a primitive cell, and a RDX molecule contains a total of 21 atoms, a total of 168 atoms. The crystal belongs to the orthorhombic crystal system, and the lattice constants (a, b, c) are

In the following embodiments of the present invention, the RDX crystal unit cell is an α-phase RDX crystal unit cell, and the unit cell model of the RDX crystal is extended to a 3×7×14 single crystal.

Carbon nanotubes include metallic carbon nanotubes CNT(13,13) and semiconducting carbon nanotubes CNT(22,0), in which metallic carbon nanotubes have a total of 832 C atoms, and semiconducting carbon nanotubes have a total of 792 C atoms. atom.

Example 1:

The RDX deflagration simulation method of the present embodiment includes:

(1) Build a model

The three-dimensional model of the RDX crystal unit cell is established by NVT thermodynamic ensemble, and the RDX crystal unit cell is calculated according to the lattice constants a, b, c (respectively ) are placed on the positive semi-axes of x, y, and z in the Cartesian coordinate system, and then the RDX crystal unit cell model is extended to a 3×7×14 single crystal model.

(2) Coupled carbon nanotubes

In the center of the single crystal model, the RDX molecules in the columnar region perpendicular to the yoz plane are removed to form a cylindrical cavity, and then metal-type carbon nanotubes of CNT (13,13) are placed for coupling to obtain a composite model;

At this time, the composite model is shown in Figure 1. There is an irregular interface between the CNT tube and the RDX crystal. This is to ensure the integrity of the RDX molecule when building the model. Only complete RDX molecules can be deleted without leaving residues. molecules or atoms, this irregularity will be improved with the relaxation optimization of the system.

Using NPT thermodynamic ensemble to optimize the relaxation of the composite model, the specific process is: set the three-dimensional periodic boundary conditions and the number of particles in the composite model, set the step size to 0.1 femtosecond and the relaxation time to 30ps; The volume and energy of the system change with time.

The NPT thermodynamic ensemble is constant temperature and pressure, which can eliminate internal stress and release excess energy during the optimization process to obtain a stable structure at normal temperature and pressure. Since the system may also involve chemical reactions during the relaxation process, a step size of 0.1 femtosecond is selected in this embodiment to obtain more accurate results. The relaxation time is 30 ps, and the relaxation time is selected according to the change of potential energy, so as to ensure that the total relaxation potential energy converges to a stable value.

After relaxation, the RDX structure model is shown in Figure 2. It can be seen from the figure that the gap between the metal-type carbon nanotubes and RDX is very uniform, indicating that the composite result is relatively ideal.

(3) Electric field induction

Using the NVE thermodynamic ensemble to apply an electric field parallel to the axial direction of the carbon nanotubes to the composite model, in this embodiment, the direction of the crystal vector a, the positive direction of the x-axis, the size is Start timing from the time when the electric field is applied, and obtain the deflagration time of RDX according to the strength of the applied electric field. The calculation formula is

U(t,E)＝U ₀ (E)+du×exp[-(tt _I )/τ(E)];

In the formula: U(t,E) is the total potential energy of the system, U ₀ (E) is the asymptotic potential energy of the product after stabilization, du is the exothermic energy of the reaction, t _I is the reaction start time, τ(E) is the black The complete decomposition time of Sorkin, t is the deflagration time; among them, U(t,E), U ₀ (E), du and τ(E) are tracked and obtained in the NVE thermodynamic ensemble.

The thermodynamic ensemble adopts NVE ensemble, three-dimensional period, its volume is constant and adiabatic, which can ensure that energy does not lose, and it is also convenient for specific analysis of energy flow.

The present invention adopts lammps software program (Large-scale Atomic/Molecular MassivelyParallel Simulator, large-scale atomic molecule parallel simulator), according to the electric field strength of input, obtains U (t, E), U ₀ (E), du and τ (E ), and then calculate the deflagration time of RDX according to the above formula, so as to control the deflagration time of RDX according to different input electric field strengths.

In this embodiment, after the relaxation time of 30 ps is over, an electric field is applied to the system starting from 30 ps, and the reaction result is observed within a reaction time of 200 ps.

Example 2:

This embodiment is basically the same as Embodiment 1, except that the carbon nanotubes used are semiconducting carbon nanotubes CNT(22,0).

Example 3:

This embodiment is basically the same as Embodiment 1, the difference is that the electric field strength is

Example 4:

This embodiment is basically the same as Embodiment 1, the difference is that the electric field strength is

Test Example 1 The influence of electric field direction and carbon nanotubes on RDX reaction

The comparative examples of Examples 1 and 2 are set respectively, and an electric field of the same size is applied according to the direction perpendicular to the carbon nanotubes (ie, the y-axis direction). In addition, the RDX model without adding carbon nanotubes is also set and the x-axis is applied to it respectively. The electric field and induction conditions in the positive direction and the positive direction of the y-axis are summarized in Table 1.

Table 1 The magnitude and direction of the applied electric field and the axial relationship with CNT

Note: "∥" means parallel, "⊥" means vertical.

After the relaxation time of 30 ps was over, an electric field was applied to the system starting at 30 ps, and the reaction results were observed within a reaction time of 200 ps. In addition to sufficient directional response, no obvious reaction occurs in the direction perpendicular to the tube axis, and no reaction occurs in the control example without embedded carbon nanotubes no matter which direction the electric field is applied. In addition, the RDX embedded with semiconducting carbon nanotubes CNT(22,0) did not react no matter whether the electric field was parallel to the tube axis or perpendicular to the tube axis. The reactions are shown in Table 2.

Table 2 Response of the system after applying an electric field

When the direction of the electric field is parallel to the axis of the metal-type CNT tube, RDX reacts. It can be seen that under the joint action of the metal-type carbon nanotubes and the electric field, RDX reacts and deflagrates. The reason why the electric field is parallel to the metal-type carbon nanotube axis leads to the reaction of RDX is that the directional movement of the metal-type carbon nanotube under the action of the electric field produces a hot spot.

The influence of test example 2 electric field intensity on RDX reaction

This test example has studied embodiment 1, 3 and 4 respectively, and its electric field intensity is respectively The effect on the RDX system of well-coupled metal-type carbon nanotubes CNT(13,13), the direction of the electric field is parallel to the tube axis. In order to describe the relationship between the applied electric field and the tube axis more vividly, a schematic diagram of the direction of the applied electric field is given 4. In the figure, the direction of the shear head is the direction of the electric field.

1. Research on the products of RDX (CNT) (RDX embedded in metal carbon nanotubes) reaction process with different electric field intensities

Track and analyze the molecular fragments at any time in each reaction process under different electric field strengths, obtain the number of molecular fragments at any time, and select the top ten molecules with the number of molecular fragments at any time to analyze and analyze their reaction process .

(1) The percentage of molecular fragments (top ten) in the system

Table 3, Table 4 and Table 5 respectively describe the application in the direction parallel to the pipe diameter The percentage of molecular fragments (top ten) in the system during the RDX (CNT) reaction process under the electric field.

Table 3(a) Electric field strength

Table 3(b) Electric field strength

It can be seen from Table 3(a) and Table 3(b) that different intermediate products correspond to different intermediate products at different times during the RDX reaction process, and the corresponding intermediate products will also change with the reaction time. After the system completes the relaxation time of 30ps, the electric field is applied, and the RDX decomposition is completed at 230ps. Although the molecular fragments of the entire reaction process have been captured, due to space limitations, all the fragments cannot be introduced one by one. For this, the molecular reaction fragments are extracted according to the time span of each interval of 40ps, that is, 30ps and 70ps are extracted. , 110ps, 150ps, 190ps, and 230ps for illustration.

It can be seen that the number of RDX molecules does not change significantly during the first 40 ps or even longer of the application of the electric field, and the main molecule is still RDX (C ₃ H ₆ O ₆ N ₆ ), accounting for 88.6145 of the total number of molecules %. There are other molecular fragments in the system, NO ₂ , C ₃ H ₆ O ₄ N ₅ , NO ₃ , C ₃ H ₆ O ₅ N ₆ , C ₆ H ₁₂ O ₈ N ₁₀ , O ₄ N ₂ , C ₃ H ₆ O ₈ N ₇ , NO, C ₃ H ₆ O ₃ N ₄ , etc., but their proportions are very small, indicating that there is no obvious reaction at this time, and there are very few The amount of molecular fragments should be caused by the decomposition and drop of individual groups in the early stage of the reaction.

When the time came to 110ps, the amount of RDX decomposition was close to half, and the proportion of intermediate product NO ₂ accounted for 10.2837%, while HO ₂ N, O ₃ N, N ₂ and other products also accounted for relatively small ratio before.

When the time is 190ps, the proportion of RDX in the components decreases to 4.6424%. At this time, H ₂ O is the most in the components, accounting for 18.8065% of the whole components, and the decomposition has basically been completed.

Finally, when the time came to 230ps, the RDX had been completely disassembled. It is found that there are H, H ₂ , O, HN ₂ and other atoms in the system. There are few reports on such atoms in the reaction products of RDX. By tracking the internal temperature of the reaction, it is found that the highest temperature can reach 7000K, that is to say, at this time The reaction temperature in the system is very high, and under the continuous action of the electric field, the molecules reacted in the system will further become gaseous or even ionized gaseous under the action of high temperature and electric field, so the reaction products become complicated after the decomposition of RDX is completed.

Table 4(a)

Table 4(b)

Table 4(a) and Table 4(b) in The reaction tracked under the electric field strength. in the X direction at Molecular fragments (top ten) during the RDX (CNT) reaction process under the action of an electric field, and the percentage of molecular fragments in the system at that time was calculated. The system is still applying an electric field after a relaxation time of 30ps, and the RDX (CNT) has completely reacted at 110ps.

The molecular fragments of the entire reaction process are captured and extracted according to the time unit of 15ps interval (the initial 30ps reaction is very small, and the RDX has been completely decomposed at 110ps later, so the interval is not taken according to 15ps), that is, from the extraction of 30ps, 60ps, 750ps, 90ps, 105ps, and 110ps are used for illustration.

It can be seen that in the first 30 ps or even longer time when the electric field is applied, the proportion of RDX molecules is 88.3731%, which has not changed significantly compared with the moment when the electric field was initially applied, indicating that there is no obvious reaction at this time occur.

When the time came to 105ps, the decomposition of RDX was nearly completed. At this time, the proportion of N ₂ as the main product in the product reached 17.1518%, and the proportion of H ₂ O was 10.6915%. At the same time, C ₃ H ₆ O ₆ N ₆ , CO _2. HO, H ₂ , NO ₂ , CO, H, NO and other products also accounted for a relatively high proportion of the components, reaching 8.7220%, 6.0167%, 5.8219%, 4.9670%, 4.6099%, 3.5278% respectively , 2.7486%, 2.5863%.

When the time is 110ps, RDX has been completely disassembled. By comparing the X direction It was found that the increase of the electric field intensity led to the accelerated decomposition of RDX. The reasons for the uncommon products that appeared later were consistent with the previous ones.

Table 5(a)

Table 5(b)

Table 5(a) and Table 5(b) are in The reaction tracked under the electric field strength. in X direction Molecular fragments (top ten) in the reaction process of RDX (CNT) under the action, and calculate the percentage in the system at that time.

After the system completes the relaxation time of 30 ps, the electric field is applied, and the RDX (CNT) has completely reacted at 74 ps. The molecular fragments that capture the entire reaction process are extracted according to the time unit of 10ps (RDX has been completely decomposed at 74.5ps, so it is not rounded according to 10ps), that is, from the extraction of 30ps, 40ps, 50ps, 60ps, 70ps, 74.5ps A few moments to illustrate.

It can be seen that in the first 10 ps of applying the electric field, the number of molecules of RDX did not change much, accounting for 87.7653% of the total number of molecular fragments in the system, which was nearly 1 percentage point lower than the 88.8982% of the initial applied electric field. The molecular fragments in the system also include NO ₂ , C ₃ H ₆ O ₄ N ₅ , NO ₃ , C ₃ H ₆ O ₅ N ₆ , C ₆ H ₁₂ O ₈ N ₁₀ , NO, C ₃ H ₆ O ₃ N ₅ , O ₄ N ₂ , CH ₂ O ₂ N ₂ , their percentages in the system are 4.2863%, 3.9118%, 0.9571%, 0.3745%, 0.2913%, 0.2913%, 0.2497%, 0.2081%, 0.2081%, indicating This is the initial stage of the reaction.

When the time came to 70ps, the RDX decomposition was almost complete.

Starting from 30ps, the proportion of RDX in the system will decrease every 10ps.

At 60ps, the proportion of RDX in the system accounted for 25.1779%, and the proportions of other products NO ₂ , N ₂ , H ₂ O, NO, HO, CO ₂ , H ₂ , CO, and HNO accounted for 9.1103% and 9.0214% respectively. , 6.9929%, 4.9110%, 3.4698%, 3.3452%, 3.0783%, 2.4199%, 2.2598%.

When the time is 70ps, RDX has been completely disassembled.

By comparing the X direction role, discovery, The electric field strength further accelerated the decomposition rate of RDX. The reasons for the uncommon products that appeared later were consistent with the previous ones.

Comparing Tables 3, 4 and 5, it is found that the RDX reaction channel can follow the following sequence: the breakage of N-NO ₂ bond forms NO ₂ molecules; the hydrogen atom transfer reaction generates NO and H ₂ O molecules; NO ₂ and NO ₃ molecules act as The intermediate products further participate in the secondary reactions; the appearance of products N ₂ , CO and CO ₂ indicates that the RDX molecule undergoes a more intense CN bond breaking reaction in the later stage of the reaction; the abnormal products H, O, O ₂ that appear at the end are due to the electric field Under the continuous action, the molecules of the system reaction will further become gaseous or even ionized gaseous under the action of high temperature and electric field, so the reaction products become more complicated after the decomposition of RDX is completed. N ₂ , H ₂ O, CO, NO ₂ , and CO ₂ molecules were the main products produced during the thermal decomposition of RDX during the simulation time. This result is consistent with the decomposition process product reported in the existing literature (Strachan A, Kober EM, Duin ACTV, et al. Thermal decomposition of RDX from reactive molecular dynamics [J]. Journal of Chemical Physics, 2005, 122(5): 54502.) are consistent, thus verifying the correctness of the calculation.

(2) The appearance of the top ten polymers

Table 6 Molecular mass polymer composition and ranking of RDX (CNT) reaction process under action (top ten)

Table 7 Molecular mass polymer composition and ranking of RDX (CNT) reaction process under action (top ten)

Table 8 Molecular mass polymer composition and ranking of RDX (CNT) reaction process under action (top ten)

During the simulation process, a large number of molecular polymers were found by tracking the reaction mass. The lechatelier principle shows that when the reaction temperature is relatively high, the reactions between molecules and inside molecules are relatively violent, and it is easy to form larger polymers. of clusters. That is, under extreme conditions, the pressure in the system is reduced through the formation of molecular aggregation of relatively large clusters, which is the content of the le chatelier principle: in an equilibrium system, if a certain condition in temperature, pressure or concentration occurs Change, then the balance of the system will move to the direction that can weaken this change. According to the quality ranking, the top ten polymers at the specified time are selected for observation to analyze the real situation of the reaction.

When tracking the atomic groups of the system, the added CNT tube is considered as a large group, and the degree of CNT tube participation in the reaction can be analyzed by changing the polymer molecular weight of the CNT tube.

The top ten polymers by quality at the selected moment are found through Table 6, Table 7, and Table 8:

Under the action of an electric field, when the time is 190ps, RDX has almost been decomposed, and the CNT tube has already broken, but at this time the largest mass group is C ₈₂₈ H ₁₁ O ₇₆ N ₁₁ , and the number of C atoms on the entire CNT is 832, it can be seen that the broken CNT tubes did not participate much in the reaction of RDX. When the time came to 230ps, the largest group at this time was C ₈₆ H ₂₀ O ₂₉ N ₁₂ , and RDX had already decomposed, indicating that the C on the ruptured CNT tube participated in the subsequent reaction.

When the electric field is applied, the maximum mass group at 75ps is C ₈₄₈ H ₁₁ O ₅₇ N ₁₈ , and at 90ps the maximum mass group becomes C ₅₀₀ H ₄₆ O ₁₀₈ N ₄₉ , indicating that the C on the subsequently damaged CNT participates in the reaction. At 110ps, the largest mass group becomes C ₁₄ H ₈ O ₁₇ N ₂₂ , and the C on the CNT has basically participated in the later reaction.

When the electric field is applied, the group with the largest mass at 50 ps is C ₈₃₀ H ₃ O ₃₉ N ₇ , and the C on the damaged CNT tube basically does not participate in the reaction. At 60 ps, the group with the largest mass is C ₇₈₃ H ₃₉ O ₇₃ N ₂₉ , indicating that the CNT tube Part of the C atoms on the top participated in the reaction, and the maximum mass was C ₁₂ H ₁₃ O ₆ N ₁₆ at 70 ps, indicating that all the C atoms on the CNT tube participated in the later reaction process.

Through the above analysis, it can be known that with the increase of the electric field intensity, the reaction speed of RDX is accelerated, and at the same time, the enthusiasm of the ruptured CNT tube to participate in the reaction is also increased with the increase of the electric field intensity.

2. Research on the decomposition speed of RDX in RDX (CNT) with different electric field strengths

Figure 5 shows the The evolution diagram of the number of RDX molecules with time under the action of three intensities of external electric fields. It can be clearly seen that all 2268 RDXs are decomposed within 220ps. And with the increase of the electric field intensity, the reaction time of RDX is advanced, and the time to complete the decomposition is shortened.

According to the tracking of the atoms in the system, it can be known that the electric field strength is RDX starts to react at 82ps, completes the reaction initialization process at 200ps, and the time required for the complete decomposition of all RDX molecules is about 118ps respectively. The electric field strength is RDX starts to react at 51ps, and at about 102ps, all RDX molecules decompose, and the time required for all RDX molecules to completely decompose is about 51ps. The electric field strength is When RDX starts to react at 36ps, all RDX molecules decompose at 73ps, and the time required for all RDX molecules to completely decompose is about 37ps; it can be seen that a greater electric field strength has a stronger promotion effect on the reaction process.

In summary, the present invention combines metal-type and semiconductor-type CNT tubes with RDX, and applies electric fields along the tube axis direction and perpendicular to the tube axis direction respectively. The results show that for RDX embedded with metal-type carbon nanotubes, the electric field Applied in the direction parallel to the tube axis, it can fully react, and there is no reaction in the direction perpendicular to the tube diameter.

In addition, for the RDX embedded with semiconducting CNT tubes, no response occurs in our simulation time scale whether the electric field is parallel to the tube diameter or perpendicular to the tube diameter.

The reaction process of RDX with the electric field parallel to the metal-type carbon nanotube axis under different electric field intensities shows that the increase in electric field strength will lead to an accelerated decomposition reaction speed of RDX (CNT). By tracking the top ten products at any time under different electric field intensities, the change law of the fixed characteristic molecules in the entire reaction process, and the top ten mass polymers at any time, it was found that the increase of the electric field and the compound (metallic CNT) Addition will lead to rapid decomposition of NO ₂ molecules and rapid generation of H ₂ O, N ₂ , NO, OH, CO and CO ₂ molecules, and it is also found that the C atoms in the CNT tubes are broken and participate in the reaction with the increase of the electric field strength enthusiasm is also increasing. After adding metal nanotubes to RDX, applying an electric field in a direction parallel to the metal nanotubes can speed up the reaction of RDX. The reason for the accelerated reaction is the combined effect of the nanotubes and the electric field.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (4)

1. a kind of hexogen detonation analogy method characterized by comprising

(1) three-dimensional stereo model for establishing hexogen crystal unit cell, by hexogen crystal unit cell according to the row of lattice constant a, b, c Array structure is individually positioned in the positive axis of the x, y, z of rectangular coordinate system, is then single by hexogen crystal unit cell model extension Brilliant model；

(2) the hexogen molecule that will be perpendicular to the cylindrical region of yoz plane in monocrystalline model center removes, and formation one is cylindric Cavity, be then placed in metal mold carbon nanotube and coupled, obtain composite model；

(3) apply the electric field for being parallel to the axis direction of the metal mold carbon nanotube to the composite model, from application electric field When start timing, the time of hexogen detonation is obtained according to the electric field strength of application.

2. hexogen detonation analogy method according to claim 1, which is characterized in that step (2) further include: use NPT Thermodynamics assemblage optimizes relaxation, detailed process to the composite model are as follows:

The three-dimensional periodic boundary condition and system number of particles for setting composite model, when setting step-length as 0.1 femtosecond and relaxation Between be 30ps；The volume and energy of system change over time.

3. hexogen detonation analogy method according to claim 2, which is characterized in that in step (3), using NVE heating power It learns assemblage and electric field is applied to the composite model；The time of hexogen detonation is obtained according to following public affairs according to the electric field strength of application Formula is calculated:

U (t, E)=U₀(E)+du×exp[-(t-t_I)/τ(E)]；

In formula: U (t, E) is total potential energy of system, U₀It (E) is the asymptotic potential energy of product after stabilization, du is the heat release energy of reaction, t_ITo react the time started, τ (E) is the time that hexogen decomposes completely, and t is the detonation time；Wherein, U (t, E), U₀(E), du and τ (E) tracks acquisition in NVE thermodynamics assemblage.

4. hexogen detonation analogy method according to claim 1-3, which is characterized in that in step (1), use NVT thermodynamics assemblage establishes the three-dimensional stereo model of hexogen crystal unit cell.