Explosion-resistant pressure vessel and design method thereof

Abstract

The invention relates to an explosion-proof pressure vessel and a design method thereof. The invention discloses a design method of an explosion-proof pressure vessel. The design method comprises the following steps: determining basic parameters; the static load design pressure value of the pressure vessel is calculated according to the formula 1; calculating to obtain a dynamic load equivalent static pressure design value of the pressure vessel according to a formula (2); calculating to obtain a composite load equivalent static pressure design value according to a formula (3); determining main body structure parameters of the pressure vessel; performing finite element checking on the structural parameters; and S6, if the check result meets the design requirement, completing the design, and if the check result does not meet the design requirement, repeating the steps S5-S6 until the check result meets the design requirement. The design method is simple and easy to implement, the design result is economical and practical, and a certain safety margin is reserved, so that the use safety of the pressure vessel in the follow-up repeated deepwater explosion simulation test process is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of deep-water explosion simulation test, in particular to an explosion-proof pressure vessel and a design method thereof. Background Art

[0002] Deep-sea explosion research is of great significance for evaluating the destructive effects of deep-sea explosives and the explosion resistance of deep-sea submersibles, deep-sea pipelines and other structures. By simulating the deep-water explosion environment in the laboratory, the experimental conditions can be precisely controlled to avoid interference from natural environmental factors, thereby more accurately studying the mechanism and effects of deep-sea explosions.

[0003] In the prior art, based on the underwater explosion similarity theory, the laboratory simulates the deep-water explosion environment by filling water and pressurizing a closed pressure vessel. However, this type of pressure vessel needs to withstand multiple loads such as hydrostatic pressure and underwater explosion shock waves and bubble pulsation at the same time. There are still gaps in the relevant design standards and specifications, and the difficulty of design and manufacturing is high, which also limits the further development and application of deep-water explosion simulation tests. Summary of the invention

[0004] In view of the shortcomings in the above-mentioned existing production technology, the applicant provides an explosion-proof pressure vessel and a design method thereof, which can fully consider the effects of hydrostatic pressure, explosion shock wave, and bubble pulsation, and at the same time adopts the finite element method to verify the structural strength of the pressure vessel under the combined action of hydrostatic pressure and deep-water explosion load. The design method is simple and easy, and the design result is economical and practical, and also leaves a certain safety margin, thereby ensuring the safety of the pressure vessel in the subsequent multiple simulated deep-water explosion tests.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for designing an explosion-proof pressure vessel comprises the following steps:

[0007] S1. Determine basic parameters, the basic parameters include the shape of the pressure vessel, the maximum simulated depth h, the maximum simulated dose W;

[0008] The maximum simulated depth h represents the maximum static water depth that can be simulated by pressurizing the pressure vessel;

[0009] The simulated maximum charge W represents the maximum amount of explosive used in the explosion test in the pressure vessel;

[0010] S2. According to the basic parameters in step S1., the static load design pressure value P1 of the pressure vessel is calculated by (Formula 1);

[0011] P1=ρgh (Formula 1)

[0012] In (Equation 1), ρ represents the density of the liquid used when the pressure vessel is pressurized; g represents the acceleration of gravity; h represents the maximum static water depth that can be simulated by pressurizing the pressure vessel;

[0013] S3. According to the basic parameters in step S1. and based on the energy equivalent calculation principle, the dynamic load equivalent static pressure design value P2 of the pressure vessel is calculated by (Formula 2);

[0014]

[0015] In (Equation 2), D represents the diameter of the pressure vessel, E represents the elastic modulus of the material used to make the pressure vessel, [σ] represents the allowable stress of the pressure vessel, α and β both represent energy absorption coefficients, which are constants, and the values ​​of α and β are related to the explosion distance R;

[0016] S4. According to the static load design pressure value P1 calculated in step S2 and the dynamic load equivalent static pressure design value P2 calculated in step S3, the composite load equivalent static pressure design value P3 is calculated by (Formula 3);

[0017] The composite load equivalent static pressure design value P3 refers to the equivalent static pressure design value of the pressure vessel under the combined action of static load and dynamic load;

[0018] P3=n(P1+P2) (Formula 3)

[0019] In (Equation 3), n represents the designed safety factor;

[0020] S5. According to the composite load equivalent static pressure design value P3 calculated in step S4, determine the main structural parameters of the pressure vessel, the main structural parameters including the main wall thickness and the wall thickness at the inlet and outlet openings;

[0021] S6. Perform finite element verification on the structural parameters in step S5 according to the composite load equivalent static pressure design value P3 calculated in step S4;

[0022] S7. If the verification result meets the design requirements, the design is completed. If not, repeat steps S5-S6 until it is satisfied.

[0023] As a further improvement of the above technical solution:

[0024] The shape of the pressure vessel includes spherical, cylindrical or a combination of spherical and cylindrical.

[0025] In step S3, the dynamic load generated by the deep-water explosion includes a strong shock wave load and a bubble pulsation load;

[0026] The energy density E1 generated by the strong shock wave load is calculated by the following formula:

[0027]

[0028] In the above formula, W represents the amount of explosive used in the explosion test, and R represents the explosion distance;

[0029] The energy density E2 generated by the bubble pulsation load is calculated by the following formula:

[0030]

[0031] In the above formula, W represents the amount of explosives used in the explosion test, and R represents the explosion distance.

[0032] In step S4, the design formula of the main body wall thickness δ1 is as follows:

[0033]

[0034] Where Q represents the empirical coefficient, P3 represents the equivalent static pressure design value of the composite load, D represents the diameter of the pressure vessel, [σ] represents the allowable stress of the pressure vessel, Represents the weld joint condition coefficient.

[0035] In step S4, the design formula of the wall thickness δ2 at the inlet and outlet openings is as follows:

[0036]

[0037] In the formula, γ represents the empirical coefficient, D c represents the opening diameter, P3 represents the equivalent static pressure design value of the composite load, and [σ] represents the allowable stress of the pressure vessel.

[0038] In step S6, the total wave method in the abaqus finite element software is used to perform verification, and the verification includes the following steps:

[0039] First, the finite element model of the pressure vessel and the internal water area are established in the abaqus finite element software;

[0040] Subsequently, a check static pressure is applied to the inside of the pressure vessel, so that static analysis calculations are carried out using abaqus finite element software, wherein the check static pressure value is equal to the static load design pressure value P1;

[0041] Next, static pressure and explosion loads are applied to the finite element model of the pressure vessel by restarting, and the result of the static analysis calculation in the previous step is specified as the initial stress, so that the restart calculation is carried out by the abaqus finite element software;

[0042] Finally, check the maximum stress distribution of key parts of the finite element model of the pressure vessel, including the tensile stress and bending stress of the main structure of the finite element model of the pressure vessel, and the concentrated stress in the opening area of ​​the finite element model of the pressure vessel.

[0043] The tensile stress is required to be less than the allowable stress [σ], the bending stress is required to be less than 1.5 [σ], and the concentrated stress is required to be less than 3 [σ].

[0044] An explosion-proof pressure vessel comprises a pressure tank body, wherein the pressure tank body is designed by using the above-mentioned design method, and an inlet and outlet hole is arranged on the top of the pressure tank body, and a sealing head is installed in cooperation with the inlet and outlet hole.

[0045] As a further improvement of the above technical solution:

[0046] The sealing head is installed in cooperation with the inlet and outlet holes through a clamp.

[0047] An observation window is provided on the pressure tank body.

[0048] The beneficial effects of the present invention are as follows:

[0049] The design method of the present invention can fully consider the effects of hydrostatic pressure, explosion shock wave and bubble pulsation on the pressure vessel in the deepwater explosion test by adopting the design methods of explosion energy equivalence, static pressure design and dynamic pressure verification; at the same time, the finite element method is used to verify the structural strength of the pressure vessel under the combined action of hydrostatic pressure and deepwater explosion load, which effectively reduces the difficulty of designing and manufacturing the pressure vessel and provides strong support for the further development and application of deepwater explosion simulation tests.

[0050] The design method of the present invention is simple and easy to implement, and can leave a safety margin, thereby effectively ensuring the safety of the designed pressure vessel in use during subsequent multiple simulated deep-water explosion tests.

[0051] The pressure vessel of the present invention can be used to carry out deep-water explosion tests simulating deep-sea environments in laboratories, so that underwater explosion test research on deep-sea explosion loads and deep-sea submersible structure models can be carried out based on the pressure vessel, solving a major basic problem of deep-sea explosion environment simulation in the field of marine engineering, and having significant economic and social effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The figure is a flow chart of the design method in the present invention.

[0053] Figure 2 It is a schematic structural diagram of the explosion-proof pressure vessel in the present invention.

[0054] Figure 3 Schematic diagram of the finite element model of the pressure vessel in Example 1 of the present invention.

[0055] Figure 4 This is a diagram showing the maximum stress distribution at key locations of the finite element model of the pressure vessel in Example 1 of the present invention.

[0056] Among them: 1. Pressure tank body; 101. Inlet and outlet holes; 2. Head; 3. Clamp; 4. Positioning rope; 5. Explosive package; 6. Test model. DETAILED DESCRIPTION

[0057] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0058] like Figure 1 As shown, a design method of an explosion-proof pressure vessel in this embodiment includes the following steps:

[0059] S1. Determine basic parameters, including the shape of the pressure vessel, the maximum simulated depth h, and the maximum simulated dose W;

[0060] The shapes of pressure vessels include spherical, cylindrical, or a combination of spherical and cylindrical;

[0061] The maximum simulated depth h represents the maximum static water depth that can be simulated by pressurizing the pressure vessel;

[0062] The simulated maximum charge W represents the maximum amount of explosive used in the explosion test in the pressure vessel.

[0063] S2. According to the basic parameters in step S1., the static load design pressure value P1 of the pressure vessel is calculated by (Formula 1);

[0064] P1=ρgh (Formula 1)

[0065] In (Equation 1), ρ represents the density of the liquid used when the pressure vessel is pressurized; g represents the acceleration of gravity; h represents the maximum static water depth that can be simulated by pressurizing the pressure vessel;

[0066] S3. According to the basic parameters in step S1. and based on the energy equivalent calculation principle, the dynamic load equivalent static pressure design value P2 of the pressure vessel is calculated by (Formula 2);

[0067]

[0068] In (Equation 2), D represents the diameter of the pressure vessel, E represents the elastic modulus of the material used to make the pressure vessel, [σ] represents the allowable stress of the pressure vessel, α and β both represent energy absorption coefficients, which are constants, and the values ​​of α and β are related to the explosion distance R;

[0069] The energy equivalent calculation principle is that the deformation energy of the pressure vessel caused by the dynamic load of deep-water explosion is consistent with the deformation energy caused by the equivalent static pressure;

[0070] The dynamic loads generated by deep-water explosions include strong shock wave loads and bubble pulsation loads;

[0071] The energy density E1 generated by the strong shock wave load is calculated by the following formula:

[0072]

[0073] In the above formula, W represents the amount of explosives used in the explosion test (kg), and R represents the explosion distance (m);

[0074] The energy density E2 generated by the bubble pulsation load is calculated by the following formula:

[0075]

[0076] In the above formula, W represents the amount of explosives used in the explosion test (kg), and R represents the explosion distance (m);

[0077] S4. According to the static load design pressure value P1 calculated in step S2 and the dynamic load equivalent static pressure design value P2 calculated in step S3, the composite load equivalent static pressure design value P3 is calculated by (Formula 3);

[0078] The equivalent static pressure design value P3 of the composite load refers to the equivalent static pressure design value of the pressure vessel under the combined action of static load and dynamic load;

[0079] P3=n(P1+P2) (Formula 3)

[0080] In (Equation 3), n represents the designed safety factor;

[0081] S5. According to the composite load equivalent static pressure design value P3 calculated in step S4, determine the main structural parameters of the pressure vessel, the main structural parameters including the main wall thickness and the wall thickness of the inlet and outlet openings;

[0082] Among them, the design formula of the main body wall thickness δ1 is as follows:

[0083]

[0084] Where Q represents the empirical coefficient, P3 represents the equivalent static pressure design value of the composite load, D represents the diameter of the pressure vessel, [σ] represents the allowable stress of the pressure vessel, Indicates the weld joint condition coefficient;

[0085] The design formula for the wall thickness δ2 at the inlet and outlet openings is as follows:

[0086]

[0087] In the formula, γ represents the empirical coefficient, D c represents the opening diameter, P3 represents the equivalent static pressure design value of the composite load, and [σ] represents the allowable stress of the pressure vessel;

[0088] S6. Perform finite element verification on the structural parameters in step S5 according to the composite load equivalent static pressure design value P3 calculated in step S4;

[0089] The total wave method in the abaqus finite element software is used for verification, which includes the following steps:

[0090] First, the finite element model of the pressure vessel and the internal water area are established in the abaqus finite element software;

[0091] Subsequently, a check static pressure is applied to the inside of the pressure vessel, and static analysis and calculation are carried out using abaqus finite element software. The check static pressure value is equal to the static load design pressure value P1.

[0092] Next, static pressure and explosion loads are applied to the finite element model of the pressure vessel by restarting, and the result of the static analysis calculation in the previous step is specified as the initial stress, so that the restart calculation is carried out by the abaqus finite element software;

[0093] Finally, check the maximum stress distribution of key parts of the finite element model of the pressure vessel, including the tensile stress and bending stress of the main structure of the finite element model of the pressure vessel, and the concentrated stress in the opening area of ​​the finite element model of the pressure vessel;

[0094] Among them, the tensile stress is required to be less than the allowable stress [σ], the bending stress is less than 1.5 [σ], and the concentrated stress is less than 3 [σ];

[0095] S7. If the verification result meets the design requirements, the design is completed. If not, repeat steps S5-S6 until it is satisfied.

[0096] like Figure 2 As shown, the explosion-proof pressure vessel of this embodiment includes a pressure tank body 1, which is designed by the above-mentioned design method. The top of the pressure tank body 1 is provided with an inlet and outlet hole 101, and a head 2 is installed at the inlet and outlet hole 101; the head 2 is installed with the inlet and outlet hole 101 through a clamp 3; and an observation window is provided on the pressure tank body 1. The pressure tank body 1 can be placed horizontally or vertically, and transparent glass is installed at the observation window to observe the internal test; the head 2 is detachably installed with the inlet and outlet hole 101 through the clamp 3, so as to facilitate personnel to enter and exit the pressure tank body 1 to arrange the test model.

[0097] When the explosion test is performed on the explosion-proof pressure vessel of this embodiment, water is filled into the pressure tank body 1, and the explosive package 5 and the test model 6 are suspended and arranged inside the pressure tank body 1 as required, wherein the test model 6 is suspended inside the pressure tank body 1 by several symmetrically arranged positioning ropes 4;

[0098] After the arrangement is completed, the head 2 is installed to form a sealed space inside the pressure tank body 1, and then the interior of the pressure tank body 1 is pressurized until its internal pressure reaches the test required pressure, and then the explosive package 5 is detonated to perform an explosion test to evaluate the explosion resistance of the test model 6.

[0099] The following is the specific examples section.

[0100] Example 1

[0101] Determine the basic parameters of the pressure vessel, where the shape of the pressure vessel is spherical, the diameter D of the pressure vessel is 7m, the maximum simulated depth h is 1500m, the maximum simulated charge W is 600gTNT explosive charge, and the allowable stress [σ] of the pressure vessel is 230MPa;

[0102] Then, according to (Formula 1), the static load design pressure value of the pressure vessel is calculated to be P1=15MPa. In this embodiment, g is 10N / kg, and ρ is 10 3 kg / m 3 ;

[0103] Based on the energy equivalence principle, the dynamic load generated by the explosion is converted into a static load pressure value for calculation. The energy density E1 generated by the strong shock wave load is 3712 J / m 2 The energy density E2 generated by the bubble pulsation load is 3291 J / m 2 ;

[0104] According to the energy equivalent calculation principle, the dynamic load equivalent static pressure design value P2 of the pressure vessel is:

[0105]

[0106] If the safety design factor n is 1.2, the equivalent static pressure design value P3 of the composite load of the pressure vessel is 23MPa;

[0107] According to the equivalent static pressure design value P3 of the composite load, the calculated value of the main wall thickness of the pressure vessel is determined to be 180mm and the wall thickness at the inlet and outlet openings is determined to be 250mm.

[0108] Establish a finite element calculation model in the abaqus finite element software, check the designed pressure vessel, and establish a good finite element model such as Figure 3 As shown;

[0109] At the same time, considering the coupling effect of hydrostatic pressure and explosion load, the stress distribution of the finite element model of the pressure vessel is analyzed and calculated using the abaqus finite element software. The calculation results are as follows: Figure 4 The maximum stress distribution of the key parts of the finite element model is shown in the following table:

[0110] Table 1 Schematic diagram of maximum stress distribution in key parts of finite element model of pressure vessel

[0111] Part Name Maximum stress value Does it meet the design requirements? Judgment Principles Observation window base 404MPa yes Local stress is less than 690MPa Inlet and outlet opening area 256MPa yes Local stress is less than 690MPa Maximum hoop tensile stress 204MPa yes Film stress is less than 230MPa Maximum hoop bending stress 25MPa yes Bending stress less than 345MPa Maximum longitudinal bending stress 229MPa yes Bending stress less than 345MPa Maximum longitudinal tensile stress 181MPa yes Film stress is less than 230MPa

[0112] It can be seen from the above table that the pressure vessel designed based on the design method of the explosion-resistant pressure vessel of this embodiment meets the use requirements and can be used to carry out explosion tests with a TNT explosive charge of 600g under a hydrostatic pressure of 15MPa.

[0113] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A method for designing an explosion-proof pressure vessel, characterized in that: The steps include: S1. Determine basic parameters, the basic parameters include the shape of the pressure vessel, the maximum simulated depth h, the maximum simulated dose W; The maximum simulated depth h represents the maximum static water depth that can be simulated by pressurizing the pressure vessel; The simulated maximum charge W represents the maximum amount of explosive used in the explosion test in the pressure vessel; S2. According to the basic parameters in step S1., the static load design pressure value P1 of the pressure vessel is calculated by (Formula 1); P1=ρgh (Formula 1) In (Equation 1), ρ represents the density of the liquid used when the pressure vessel is pressurized; g represents the acceleration of gravity; h represents the maximum static water depth that can be simulated by pressurizing the pressure vessel; S3. According to the basic parameters in step S1. and based on the energy equivalent calculation principle, the dynamic load equivalent static pressure design value P2 of the pressure vessel is calculated by (Formula 2); In (Equation 2), D represents the diameter of the pressure vessel, E represents the elastic modulus of the material used to make the pressure vessel, [σ] represents the allowable stress of the pressure vessel, α and β both represent energy absorption coefficients, which are constants, and the values ​​of α and β are related to the explosion distance R; S4. According to the static load design pressure value P1 calculated in step S2 and the dynamic load equivalent static pressure design value P2 calculated in step S3, the composite load equivalent static pressure design value P3 is calculated by (Formula 3); The composite load equivalent static pressure design value P3 refers to the equivalent static pressure design value of the pressure vessel under the combined action of static load and dynamic load; P3=n(P1+P2) (Formula 3) In (Equation 3), n represents the designed safety factor; S5. According to the composite load equivalent static pressure design value P3 calculated in step S4, determine the main structural parameters of the pressure vessel, the main structural parameters including the main wall thickness and the wall thickness at the inlet and outlet openings; S6. Perform finite element verification on the structural parameters in step S5 according to the composite load equivalent static pressure design value P3 calculated in step S4; S7. If the verification result meets the design requirements, the design is completed. If not, repeat steps S5-S6 until it is satisfied.

2. The design method according to claim 1, characterized in that: The shape of the pressure vessel includes spherical, cylindrical or a combination of spherical and cylindrical.

3. The design method according to claim 1, characterized in that: In step S3, the dynamic load generated by the deep-water explosion includes a strong shock wave load and a bubble pulsation load; The energy density E1 generated by the strong shock wave load is calculated by the following formula: In the above formula, W represents the amount of explosive used in the explosion test, and R represents the explosion distance; The energy density E2 generated by the bubble pulsation load is calculated by the following formula: In the above formula, W represents the amount of explosives used in the explosion test, and R represents the explosion distance.

4. The design method according to claim 1, characterized in that: In step S4, the design formula of the main body wall thickness δ1 is as follows: Where Q represents the empirical coefficient, P3 represents the equivalent static pressure design value of the composite load, D represents the diameter of the pressure vessel, [σ] represents the allowable stress of the pressure vessel, Represents the weld joint condition coefficient.

5. The design method according to claim 1, characterized in that: In step S4, the design formula of the wall thickness δ2 at the inlet and outlet openings is as follows: In the formula, γ represents the empirical coefficient, D c represents the opening diameter, P3 represents the equivalent static pressure design value of the composite load, and [σ] represents the allowable stress of the pressure vessel.

6. The design method according to claim 1, characterized in that: In step S6, the total wave method in the abaqus finite element software is used to perform verification, and the verification includes the following steps: First, the finite element model of the pressure vessel and the internal water area are established in the abaqus finite element software; Subsequently, a check static pressure is applied to the inside of the pressure vessel, so that static analysis calculations are carried out using abaqus finite element software, wherein the check static pressure value is equal to the static load design pressure value P1; Next, static pressure and explosion loads are applied to the finite element model of the pressure vessel by restarting, and the result of the static analysis calculation in the previous step is specified as the initial stress, so that the restart calculation is carried out by the abaqus finite element software; Finally, check the maximum stress distribution of key parts of the finite element model of the pressure vessel, including the tensile stress and bending stress of the main structure of the finite element model of the pressure vessel, and the concentrated stress in the opening area of ​​the finite element model of the pressure vessel.

7. The design method according to claim 6, characterized in that: The tensile stress is required to be less than the allowable stress [σ], the bending stress is required to be less than 1.5 [σ], and the concentrated stress is required to be less than 3 [σ].

8. An explosion-proof pressure vessel, characterized in that: The invention comprises a pressure tank body (1), wherein the pressure tank body (1) is designed by using the design method according to any one of claims 1 to 7, wherein an inlet and outlet hole (101) is arranged on the top of the pressure tank body (1), and a sealing head (2) is installed in cooperation with the inlet and outlet hole (101).

9. The explosion-proof pressure vessel according to claim 8, characterized in that: The sealing head (2) is mounted in cooperation with the inlet and outlet hole (101) via a clamp (3).

10. The explosion-proof pressure vessel according to claim 8, characterized in that: An observation window is provided on the pressure tank body (1).

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