CN110689640A - Risk judgment method for composite propellant mixed torque - Google Patents

Abstract

The invention belongs to the field of composite propellants, and specifically discloses a risk determination method for mixed torque of composite propellants. The method includes obtaining a torque early warning value coefficient and a torque safety value coefficient of formula A; calculating the friction sensitivity of formula A mixed explosion , the friction sensitivity of the explosion critical point of formula A and the friction sensitivity of the explosion critical point of formula B; use the above parameters to calculate the correction coefficient of torque warning value and the correction coefficient of torque safety value; finally determine the mixed torque early warning value and mixed torque safety value, judge Whether the actual mixed torque is less than the mixed torque safety value, if so, the mixing process is safe; if not, the mixing process is unsafe, and the machine is set to stop when the actual mixed torque is greater than the mixed torque early warning value. The present invention formulates a complete risk determination method for the torque characterizing mixing safety, and can be applied to various working conditions of all vertical mixers, thereby effectively eliminating potential safety hazards in the mixing process and preventing explosions.

Description

A risk determination method for compound propellant mixing torque

technical field

The invention belongs to the field of composite propellants, and more particularly relates to a risk determination method for the mixing torque of composite propellants.

Background technique

The main components of composite propellants are high polymer binders, inorganic oxidants and combustion agents, as well as high-energy additives, plasticizers, curing agents, curing catalysts, antioxidants, combustion catalysts and process additives. The process of preparing the composite propellant is to use the high polymer binder as the elastic matrix, add a large amount of oxidant and metal fuel powder, and press the viscous fluid on the surface of the multiphase mixture through mechanical mixing. Among them, mechanical mixing is a process in which flammable and explosive powder is passivated and desensitized by mechanical force, and is an indispensable and very dangerous process in the production of explosives.

The vertical mixer is the key equipment to complete the compound propellant mixing process. Its mixing safety (that is, whether the slurry explodes or not) is related to the sensitivity of the propellant, the slurry capacity, the solid content, the slurry state, the mixing speed, and the slurry viscosity. It is related to factors such as the structural parameters of the mixer, and the mixing torque value represents the magnitude of the external force acting on the slurry, which is an important quantitative index for safety. There are few literature reports on the safety research of hybrid composite propellants, and there is no perfect risk determination method for the hybrid safety, especially the torque safety value. However, with the continuous development of composite propellants towards high energy and high burning rate, their various sensitivities and the degree of danger also increase, and the requirements for mixing safety, stability and mixing quality increase accordingly. In recent years, the explosion accident of domestic mixer is almost once a year, which has brought great losses to propellant manufacturing.

It is of great and far-reaching significance to establish a risk determination method for the mixing torque of composite propellants in combination with previous accident records, mixing structural parameters, process parameters and slurry formulation characteristics, so as to prevent the occurrence of explosion events.

SUMMARY OF THE INVENTION

In view of the above shortcomings and/or improvement requirements of the prior art, the present invention provides a method for risk determination of mixed torque of composite propellants, wherein the friction sensitivity is used as the evaluation index, and the mixed torque early warning value and the mixed torque safety value are obtained by calculation. , to determine the risk of compound propellant mixing torque, so it is especially suitable for applications such as compound propellant preparation.

In order to achieve the above object, the present invention proposes a risk determination method for the mixing torque of composite propellants, which comprises the following steps:

S1 determines the torque explosion value, torque pre-warning value and torque safety value of formula A according to the torque history data of the mixed accident, so as to obtain the torque pre-warning coefficient and torque safety coefficient of formula A;

S2 calculates the friction sensitivity of the mixed explosion of formula A, the friction sensitivity of the explosion critical point of formula A, and the friction sensitivity of the explosion critical point of formula B according to the force increment of the drug paddle and the speed increment of the drug paddle;

S3 utilizes the torque warning coefficient and torque safety factor of the formula A obtained in the step S1 and the friction sensitivity number of the mixed explosion of the formula A obtained in the step S2, the friction sensitivity number of the explosion critical point of the formula A and the explosion critical point of the formula B. Calculate the correction coefficient of torque warning value and the correction coefficient of torque safety value by friction sensitivity;

S4 determines the mixed torque early warning value and the mixed torque safety value according to the torque early warning value correction coefficient and the torque safety value correction coefficient obtained in the step S3, and judges whether the actual mixed torque is less than the mixed torque safety value. If so, the mixing process is safe, if not , then the mixing process is unsafe, and it is set to stop when the actual mixing torque is greater than the mixing torque pre-warning value.

As a further preference, in the step S1, the formula A torque warning coefficient is calculated using the following formula,

where k ₁ is the torque pre-warning coefficient of formula A, T _{A-mixed explosion} is the torque explosion value of formula A, and T _A-prewarning is the torque pre-warning value of formula A;

Use the following formula to calculate the torque safety factor of Formula A,

In the formula, k ₂ is the torque safety factor of formula A, and T _A-safety is the torque safety value of formula A.

As further preferably, in the step S2, calculating the friction sensitivity of the mixed explosion of formula A includes the following sub-steps:

S21 uses the following formula to calculate the force increment ΔP of the slurry before the mixed explosion of the formula A _{slurry-mixed explosion} ,

In the formula, d _blade is the diameter of the blade, and the area S is the effective force bearing _area of the blade;

S22 uses the following formula to calculate the slurry velocity increment _Δvhe ,

Δv _combined = (πN _public d _public + πN _self d _blade )

In the formula, N is _the rotation speed of the blade, d is _the diameter of the rotation of the blade, and N is the rotation speed _of the blade;

S23 utilizes the ΔP _{slurry-mixed explosion} obtained in the step S21 and the Δv obtained in _the step S22 to calculate the friction sensitivity number E _{A-mixed explosion} of the formula A mixed explosion according to the following formula,

As further preferably, in the step S2, calculating the friction sensitivity of the critical point of explosion of formula A includes the following sub-steps:

S24 test formula A at the explosion critical point, that is, when the explosion probability is 17%, the force increase of the slurry ΔP _A-critical and the speed increase of the slurry Δv _A-critical ;

S25 calculates the friction sensitivity number E _A-critical at the explosion critical point of formula A according to the following formula,

As a further preference, in the step S2, calculating the friction sensitivity of the critical point of explosion of formula B includes the following sub-steps:

S26 test formula B is at the critical point of explosion, that is, when the explosion probability is 17%, the force increase of the slurry ΔP _B-critical and the velocity increase of the slurry Δv _B-critical ;

S27 calculates the friction sensitivity number E _B-critical at the explosion critical point of formula B according to the following formula,

As a further preference, the step S3 includes the following sub-steps:

S31 calculates the friction sensitivity correction coefficient k ₃ of formula A according to the following formula,

S32 judges whether the friction sensitivity number E _B-critical of the mixed explosion of formula B is less than or equal to the friction sensitivity number E _A-critical of the explosion critical point of formula A, if yes, then go to step S33, if not, then go to step S34;

S33 sets the torque early warning value correction coefficient k _{early warning} =k ₁ k ₃ , and simultaneously sets the torque safety value correction coefficient k _safe =k ₂ k ₃ ;

S34 sets the torque early warning value correction coefficient k _{early warning} =nk ₁ k ₃ , and simultaneously sets the torque safety value correction coefficient k _safe =nk ₂ k ₃ , n>1.

As a further preference, the value of n in the step S34 is preferably 1.5-2.

As a further preference, the step S4 includes the following sub-steps:

S41 utilizes the EB- _critical obtained in the step S2, and calculates the torque critical value TB- _critical of the formula B according to the following formula,

S42 utilizes the T _B-critical , k _{early warning} and k _safety , respectively, according to the following formula, calculates the mixed torque early warning value T _{mixed early warning} and the mixed torque safety value T _{mixed safety} ,

S43 judges whether the actual _hybrid torque T is less than the hybrid torque safety value T _{hybrid safe} , if yes, the hybrid process is safe, if not, the hybrid process is not safe, and sets when the actual _hybrid torque T is greater than the set value When the mixed torque early warning value T is set to the _{mixed early} warning value, the machine will stop.

In general, compared with the prior art, the above technical solutions conceived by the present invention mainly have the following technical advantages:

1. The present invention uses the friction sensitivity as the safety evaluation index, and formulates a complete risk determination method for the torque that characterizes the hybrid safety, thereby providing guidance for determining the hybrid torque early warning value and the hybrid torque safety value, and can be applied to all The various working conditions of the vertical mixer, such as different structural parameters, process parameters and formula characteristics, can effectively eliminate the hidden safety hazards in the mixing process and prevent the occurrence of explosion accidents. Verification, with high reliability;

2. In particular, the present invention determines whether formula B is more dangerous than formula A by comparing the critical friction sensitivity of formula A and formula B, thereby determining the torque early warning correction coefficient and the torque safety value correction coefficient, and then the mixed torque early warning value and the torque safety value correction coefficient can be determined. The mixed torque safety value is accurately optimized to make the risk determination more accurate and reliable.

Description of drawings

FIG. 1 is a flow chart of a method for risk assessment of a compound propellant mixing torque provided by a preferred embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

As shown in FIG. 1 , an embodiment of the present invention provides a method for risk determination of the mixing torque of a composite propellant, and the method includes the following steps:

S1 determines the torque explosion value T _{A-mixed explosion} of formula A according to the torque history data of the mixed accident, the torque pre-warning value T _{A- early warning} and the torque safety value T _A-safe , which are calculated by formula (1) and formula (2) respectively Formula A torque warning coefficient k ₁ and formula A torque safety coefficient k ₂ ,

S2 uses formula (3) to calculate the friction sensitivity of formula A mixed explosion E _{A-mixed explosion} , the friction sensitivity of formula A explosion critical point E _A-critical and the friction sensitivity of formula B explosion critical point E _B-critical ,

In the formula, E _friction is the degree of friction sensitivity, ΔP is the force increment of the slurry (take the average pressure of the _blade on the slurry), and Δv _is the speed increment of the slurry (take the maximum linear velocity at the tip of the blade). The formula can comprehensively consider the influence of the structural parameters of the mixing equipment, the process parameters and the characteristics of the slurry formulation;

S3 utilizes the torque warning coefficient k ₁ and torque safety factor k ₂ of the formula A obtained in step S1 and the friction sensitivity number E A of the mixed explosion of the formula A obtained in step S2—the friction sensitivity number E _{A of the mixed explosion} and the explosion critical point of the formula _{A - Friction sensitivity of critical} and formula B explosion critical points E _{B - critical} calculation torque warning value correction coefficient k _{early warning} and torque safety value correction coefficient k _safety ;

S4 uses the torque early warning value correction coefficient k _{early warning} and the torque safety value correction coefficient k obtained in step S3 to _safely determine the mixed torque early warning value T _{mixed early warning} and mixed torque safety value T _{mixed safety} , and determine whether the actual mixed torque T _{actual mixed torque} is smaller than the mixed torque The safety value T is the _{mixing safety} . If yes, the mixing process is safe. If not, the mixing process is unsafe, and it is set to stop when the _actual mixing torque T is greater than the mixing torque warning value T _{mixing warning} .

Further, step S2 includes the following sub-steps:

S21 calculates the force increment ΔP of the slurry before the mixed explosion of the formula A according to the formula (4) _{slurry-mixed explosion} ,

In the formula, d _blade is the diameter of the blade, and the _area S is the effective force bearing _area of the blade.

In the formula, H is the material height function, and its expression is shown in formula (6), δ is the pot bottom clearance height, F(x) is the blade height function, G(y) is the blade width expansion line function,

In the formula, W is the weight of the mixed slurry, _ρ is the density of the slurry (ρ=100/∑(mi/di), mi is the mass percentage of the formula components, and di is the density value of the components in the formula), and V is the _{effective blade} is the total volume of the paddle immersed in the slurry, and r _paddle is the radius of the paddle (r _paddle =d _paddle /2);

S22 calculates _the slurry velocity increment Δv according to formula (7),

Δv _combined = (πN _public d _public + πN _self d _blade ) (7)

In the formula, N is _the revolution speed of the blade, d is _the revolution diameter of the blade, and N is the rotation speed _of the blade;

S23 utilizes the ΔP _{slurry-mixed explosion} obtained in step S21 and the Δv sum obtained in step S22 _, and calculates the friction sensitivity number E _{A-mixed explosion} of formula A mixed explosion according to formula (8),

S24, through the friction sensitivity meter, test formula A at the explosion critical point, that is, when the explosion probability is 17%, the force increment of the slurry ΔP _A-critical and the speed increase of the slurry Δv _A-critical ;

S25 calculates the friction sensitivity E _A-critical at the explosion critical point of formula A according to formula (9),

S26 uses friction sensitivity tester to test other formulas, such as formula B at the critical point of explosion, that is, when the explosion probability is 17%, the force increment of the slurry ΔP _B-critical and the speed increase of the slurry Δv _B-critical ;

计算配方B爆炸临界点的摩擦感度数E_B-临界。S27 according to the formula

Calculate the friction sensitivity E _B-critical at the explosion critical point of formula B.

Further, step S3 includes the following sub-steps:

计算配方A的摩擦感度数修正系数k₃；S31 according to the formula

Calculate the friction sensitivity correction coefficient k ₃ of formula A;

S32 judges whether formula B is more sensitive (dangerous) than formula A, that is, whether it satisfies E _{B-critical≤E A-critical} , if yes, then formula B is safer than formula A, go to step S33, if not, formula B is more than formula B A is dangerous, go to step S34;

S33 sets the torque early warning value correction coefficient k _{early warning} =k ₁ k ₃ , and simultaneously sets the torque safety value correction coefficient k _safe =k ₂ k ₃ ;

S34 sets the torque warning value correction coefficient k _{early warning} =nk ₁ k ₃ , and sets the torque safety value correction coefficient k _safe =nk ₂ k ₃ , n>1, and more preferably 1.5-2.

Further, step S4 includes the following sub-steps:

计算配方B的扭矩临界值T_B-临界，该计算公式适用于所有的立式混合机；S41 utilizes the _EB-critical obtained in step S2, according to the formula

Calculate the torque critical value T _B-critical of formula B, which is applicable to all vertical mixers;

计算混合扭矩预警值T_混合预警和混合扭矩安全值T_混合安全；S42 utilizes T _B-critical , k _{early warning} and k _safety , respectively according to the formula

Calculate the mixed torque early warning value T _{mixed early warning} and the mixed torque safety value T _{mixed safety} ;

S43 judges whether the actual _mixed torque T is less than the mixed torque safety value T _{mixed safe} , if so, the mixing process is safe, if not, the mixing process is not safe, and set the pre-warning when the _actual mixed torque T is greater than the mixed torque The value T is _{mixed with early warning} to shut down.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be Included in the protection scope of the present invention.

Claims (8)

1. A risk assessment method for hybrid propellant torque is characterized by comprising the following steps:

s1, determining a torque explosion value, a torque early warning value and a torque safety value of the formula A according to the torque historical data of the mixed accident, and thus obtaining a torque early warning coefficient and a torque safety coefficient of the formula A;

s2, calculating the friction sensitivity degree of the mixed explosion of the formula A, the friction sensitivity degree of the explosion critical point of the formula A and the friction sensitivity degree of the explosion critical point of the formula B according to the force increment and the speed increment of the paddle;

s3, calculating a torque early warning value correction coefficient and a torque safety value correction coefficient by using the torque early warning coefficient and the torque safety coefficient of the formula A obtained in the step S1, and the friction sensitivity number of the formula A mixed explosion, the friction sensitivity number of the formula A explosion critical point and the friction sensitivity number of the formula B explosion critical point obtained in the step S2;

s4, determining a hybrid torque early warning value and a hybrid torque safety value according to the torque early warning value correction coefficient and the torque safety value correction coefficient obtained in the step S3, judging whether the actual hybrid torque is smaller than the hybrid torque safety value, if so, the hybrid process is safe, if not, the hybrid process is unsafe, and setting the device to stop when the actual hybrid torque is larger than the hybrid torque early warning value.

2. The method for determining the risk of hybrid torque of a composite propellant according to claim 1, wherein in step S1, a formula A torque warning coefficient is calculated using the following formula,

in the formula k₁Torque early warning coefficient, T, for formulation a_{A-mixed explosion}Torque explosion value, T, for formulation A_{A-early warning}The torque early warning value of formula A;

the formula a torque safety factor was calculated using the following formula,

in the formula k₂Torque safety factor, T, for formulation a_A-safetyTorque safety values for formulation a.

3. The method for determining the risk of hybrid propellant torque as claimed in claim 1 or 2, wherein the step S2 of calculating the friction sensitivity number of the formula a hybrid explosion includes the following sub-steps:

s21 calculation of the increment of force Δ P of the mixed explosive slurry of formulation A using the following formula_{Slurry-mix explosion}，

In the formula (d)_BladeIs the diameter of the blade, S_{Area of}Is the effective stressed area of the blade;

s22 calculation of slurry velocity increment Δ v using the following equation_{Combination of Chinese herbs}，

Δv_{Combination of Chinese herbs}＝(πN_Publicd_Public+πN_Fromd_Blade)

In the formula, N_PublicRevolution speed of the blade, d_PublicIs the revolution diameter of the blade, N_FromThe rotation speed of the paddle is the rotation speed;

s23 Using Δ P obtained in the step S21_{Slurry-mix explosion}And Δ v obtained in said step S22_{Combination of Chinese herbs}The degree of frictional sensitivity E of the mixed explosion of formulation A was calculated according to the following formula_{A-mixed explosion}，

4. The method for determining the risk of hybrid propellant torque as claimed in claim 1, wherein the step S2 of calculating the friction sensitivity number of the explosion critical point of the formulation a comprises the following sub-steps:

s24 test for the stress increment delta P of the formula A at the explosion critical point, namely the explosion probability of 17 percent_A-criticalAnd the velocity increment of the slurry Δ v_A-critical；

S25 the degree of frictional sensitivity E at the explosion critical point of formulation A was calculated according to the following formula_A-critical，

5. The method for determining the risk of hybrid propellant torque as claimed in claim 1, wherein the step S2 of calculating the friction sensitivity number of the explosion critical point of the formulation B comprises the following sub-steps:

s26 test for the stress increment delta P of the formula B when the explosion critical point, namely the explosion probability is 17 percent_B-criticalAnd the velocity increment of the slurry Δ v_B-critical；

S27 the degree of frictional sensitivity E at the explosion critical point of formulation B was calculated according to the following formula_B-critical，

6. The method for determining the risk of hybrid torque of a composite propellant according to claim 1, wherein the step S3 includes the substeps of:

S31A coefficient k for correcting the degree of friction sensitivity of formulation A was calculated according to the following equation₃，

S32 judging degree of friction sensitivity E of formula B mixed explosion_B-criticalWhether or not the degree of frictional sensitivity E is less than or equal to the explosion critical point of the formula A_A-criticalIf yes, go to step S33, otherwise, go to step S34;

s33 setting a correction coefficient k of the torque early warning value_{Early warning}＝k₁k₃While setting a torque safety value correction coefficient k_Security＝k₂k₃；

S34 setting a correction coefficient k of the torque early warning value_{Early warning}＝nk₁k₃While setting a torque safety value correction coefficient k_Security＝nk₂k₃，n＞1。

7. The method for determining the risk of hybrid torque of the composite propellant according to claim 6, wherein n in the step S34 preferably takes a value of 1.5-2.

8. The method for determining the risk of hybrid torque of a composite propellant according to any one of claims 1 to 7, wherein the step S4 includes the substeps of:

s41 Using E obtained in the step S2_B-criticalCalculating the torque threshold T for formulation B according to_B-critical，

S42 using the T_B-critical、k_{Early warning}And k_SecurityRespectively calculating a hybrid torque early warning value T according to the following formula_{Hybrid early warning}And a hybrid torque safety value T_{Hybrid security}，

S43 judges the actual hybrid torque T_{Actual mixing torque}Whether it is less than the safe value T of the mixed torque_{Hybrid security}If yes, the mixing process is safe, if no, the mixing process is unsafe, and the actual mixing torque T is set_{Actual mixing torque}Greater than the early warning value T of the mixed torque_{Hybrid early warning}And stopping the machine.

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