A method for simulating vertical burning of a flame retardant material
By using a vertical combustion simulation method for flame-retardant materials, and by fitting heat release rates and model simulation, the problems of cumbersome experiments and large errors in existing technologies have been solved. This method enables rapid and accurate screening of the optimal ratio of flame-retardant materials, reducing costs and improving safety and environmental protection.
Patent Information
- Application Number
- CN202211729301.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-30
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2042-12-30
AI Technical Summary
Existing technologies require numerous arduous and error-prone physical experiments during the development of flame-retardant materials, resulting in high costs, long cycles, high risks, and environmental pollution. Furthermore, conventional methods such as the limiting oxygen index method and the UL94 standard are inconsistent, making it difficult to accurately determine the flame-retardant performance of materials.
A vertical combustion simulation method for flame-retardant materials was adopted. By linearly fitting the average heat release rate, the combustion performance of different ratios was simulated in the vertical combustion model. The burner activation event was set to record the spread of afterflame and afterglow, and the optimal ratio was quickly selected.
It enables rapid and accurate screening of the optimal ratio of flame-retardant materials, reduces human and equipment errors, lowers costs, improves safety and environmental protection, and provides a reference for optimizing the performance of flame-retardant materials.
Smart Images
Figure CN116660451B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the field of material combustion simulation analysis, and particularly relates to a simulation method for vertical combustion of flame-retardant material. BACKGROUND
[0002] In recent years, electrical fires account for an increasing proportion of fires in the country. In order to do a good job in electrical fire prevention and improve the fireproof performance of materials, it is necessary to modify or develop new fireproof materials. In the early stage of developing new flame-retardant materials, experiments on the formula of raw materials need to be compared. Different types and different amounts of base materials, flame retardants and coupling agents are mixed together, and the flame-retardant performance of different combinations is studied respectively to obtain the optimal ratio. At present, the limiting oxygen index method and the UL94 standard are commonly used to determine the flame-retardant performance of materials, but research results show that the two methods are not consistent, and the oxygen index alone is not enough to characterize the flame-retardant performance of materials, and the vertical combustion test needs to be combined to determine it together. After analyzing the vertical combustion test of flame-retardant materials with different ratios, the optimal combination of flame-retardant performance is selected by observing the experimental phenomena.
[0003] According to the regulations, the vertical combustion experiment of the flame-retardant material is carried out, the afterglow and afterflame time of the material combustion are recorded, and whether the afterglow and afterflame spread to the clamp is observed, so that the flame-retardant grade of the material can be determined and the flame-retardant performance of different formulas can be preliminarily screened. The specific physical experiment needs to build a test system to carry out vertical combustion of flame-retardant materials with different ratios. This process needs to be tried many times, and the workload is heavy and the error is large. Once the adjustment is wrong, the product may have different properties, or it may not meet the specifications, resulting in waste, high cost of rework, and even harm to the health of the operating personnel. SUMMARY
[0004] In view of the problems in the prior art, the present application aims to provide a simulation method for vertical combustion of flame-retardant material. The simulation can simulate the vertical combustion performance of flame-retardant materials with different ratios, quickly screen the optimal ratio in the early stage of product development, has a short modeling time, small manual and equipment errors, rapid and accurate experimental results, is green and environmentally friendly, has safety and economy, provides a reference for optimizing the performance of flame-retardant materials, and has important significance for the development of material products in the industry.
[0005] A simulation method for vertical combustion of flame-retardant material, comprising the following steps:
[0006] Mixing the base material and the flame retardant to form a flame-retardant material, linear fitting the heat release rate of the flame-retardant material to obtain an average heat release rate, and inputting the average heat release rate and parameters of the base material and the flame retardant into a vertical combustion model;
[0007] Setting a first activation event of the torch, running the simulation, and recording the first simulation result;
[0008] setting a second activation event of the torch, running the simulation, and recording a second simulation result;
[0009] determining the flame-retardant grade of the flame-retardant material according to the first simulation result and the second simulation result.
[0010] Further, the vertical combustion model is a square open environment with a length of 0.5 m, a width of 0.5 m, and a height of 0.75 m, and the periphery and the upper part are set as open surfaces, and the ground is set as an inert surface.
[0011] Further, the vertical combustion model is provided with a simulation clamp, a sample material, a simulation torch, and a cotton pad.
[0012] Further, a piece of absorbent cotton with a length of 50 mm, a width of 50 mm, and a height of 6 mm is arranged in the center of the ground; an alcohol torch is arranged 0.3 m above the piece of absorbent cotton; a long strip sample is arranged 10 mm above the torch; and a simulation clamp is arranged 6 mm above the upper end of the sample.
[0013] Further, the diameter of the torch is 9.6±0.3 mm.
[0014] Further, the long strip sample has a length of 130 mm, a width of 13 mm, and a thickness of 13 mm.
[0015] Further, the parameters of the base material and the flame retardant include density, ignition point, thermal conductivity, and specific heat.
[0016] Further, the first simulation result includes the first afterflame time and the afterglow spread; and the second simulation result includes the second afterflame time and the afterglow time, and whether the afterglow spreads.
[0017] Compared with the prior art, the present application has the following beneficial effects:
[0018] The vertical combustion model of the present application can simply and quickly simulate the vertical combustion experiments of a plurality of different proportions of ingredients, can quickly screen the optimal proportion in the early stage of product development, has high flexibility, and solves the problems of large workload, long experimental period, high cost, high risk coefficient, and environmental pollution in the early stage of product development. The simulation data obtained by the present application are fast and accurate, the spread process of the flame and the smoke particles can be repeatedly observed, the temperature slice or the heat release rate change process with time at any position can be obtained, the flame-retardant grade of the material can be quickly determined, and the performance of the flame-retardant material is optimized, and the best proportion of the flame-retardant material is found, thereby providing a reference. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 The flowchart of the simulation method of the present application is shown in the figure;
[0020] Figure 2A vertical burning model diagram established for a fire dynamics simulation software (FDS, Fire Dynamics Simulator);
[0021] Figure 3 The burning phenomenon and temperature slice of the sample material of the 10.1s third formula; wherein (a) is the burning phenomenon, and (b) is the temperature slice;
[0022] Figure 4 The burning phenomenon and temperature slice of the sample material of the 10.1s third formula; wherein (a) is the burning phenomenon, and (b) is the temperature slice;
[0023] Figure 5 The temperature slice at a position 2mm below the clamp when the sample material of the 10.1s third formula burns;
[0024] Figure 6 The burning phenomenon and temperature slice of the sample material of the 20.3s third formula; wherein (a) is the burning phenomenon, and (b) is the temperature slice;
[0025] Figure 7 The temperature slice at a position 2mm below the clamp when the sample material of the 20.3s third formula burns;
[0026] Figure 8 A schematic diagram of an activation event of a torch. DETAILED DESCRIPTION
[0027] In order to make the purpose, simulation method and advantages of the present application more clear and explicit, the present application is further described in detail below in combination with the drawings and examples.
[0028] Reference is made to Figure 1 A simulation method for vertical burning of a flame-retardant material, comprising the following steps:
[0029] Step (1), a vertical burning model is established according to GB / T 2408-2008, and parameters and boundary conditions of the vertical burning model are set:
[0030] The vertical burning model comprises a simulation clamp, a sample material, a simulation torch and a cotton pad; the vertical burning model is a square open environment with a length of 0.5m, a width of 0.5m and a height of 0.75m, and the four sides and the top are set as open surfaces, and the ground is set as an inert surface.
[0031] Specifically, the vertical burning experiment according to GB / T 2408-2008 should be carried out in an environment with ventilation on four sides and the top, and a square open environment with a length of 0.5m, a width of 0.5m and a height of 0.75m is set, the four sides and the top of the model are set as OPEN, i.e. open surfaces, and the floor is set as Inert, i.e. an inert surface;
[0032] Step (2), determine the individual parameters of different base materials and flame retardants, including density, ignition point, thermal conductivity, specific heat and average heat release rate, linearly fit the heat release rate parameters of the base materials and flame retardants according to different proportions, input the formula parameters into the vertical combustion model; determine the parameters of the cotton pad, the experimental burner and the initial experimental environment temperature, and input each parameter into the vertical combustion model;
[0033] The parameters of each raw material can be measured by corresponding instruments; a 50mm long, 50mm wide and 6mm high absorbent cotton sheet is arranged in the center of the floor, the cotton pad is made of 100% absorbent cotton, and the ignition point is about 156℃; an alcohol burner is arranged 0.3m above the cotton sheet from the floor, according to GB / T 2408-2008, the experimental burner needs to meet the requirements of IEC 60695-11-4:2004 flame A, B or C. In the relevant standard, the fuel used in the experiment requires a purity of not less than 98% methane, and the diameter of the burner is 9.6±0.3mm; a long strip sample with a length of 130mm, a width of 13mm and a thickness of 13mm is arranged 10mm above the burner, and the density, ignition point, thermal conductivity, specific heat and average heat release rate of the flame-retardant material are measured by experimental instruments; a square block is arranged on the upper end of the sample with a length of 6mm, which is used to set the simulation clamp; according to GB / T 2408-2008, the experimental environment temperature is set to 25℃, and the relative humidity is 50%;
[0034] (3) Set the first activation event of the burner, set the fire supply time to 10s, run the simulation, record the first afterflame time t1 after the fire source is removed, and judge whether the afterglow spreads to the clamp;
[0035] (4) Set the second activation event of the burner, set the second fire supply time to 10s, run the simulation, record the second afterflame time t2 and the afterglow time t3, judge whether the afterglow spreads to the clamp, and judge the flame-retardant level according to Table 1.
[0036] Table 1
[0037]
[0038] According to the recorded time, judge whether it is less than a certain number of seconds, for example, the first afterflame time is less than 10s, the second afterflame and afterglow time is less than 10s, and the flame-retardant material is v-0 level, and the time limit for different levels is different.
[0039] In the vertical combustion model, any observation point position can be selected to obtain the temperature slice or the change process of the flame spread rate with time.
[0040] To illustrate the present application in detail, the following is described with an example of a certain flame-retardant material EVA, wherein the base material is EVA, the flame retardant is magnesium hydroxide MH, and there are three formulations, by mass fraction, Formulation One is that the base material is 600 parts, the flame retardant is 400 parts, Formulation Two is that the base material is 500 parts, the flame retardant is 500 parts, and Formulation Three is that the base material is 400 parts, the flame retardant is 600 parts.
[0041] The following is simulated with the example of the flame-retardant material of Formulation Three.
[0042] Step (1), according to GB / T 2408-2008 vertical burning test should be carried out in an environment with ventilation on four sides and above, a square open environment with a length of 0.5m, a width of 0.5m, and a height of 0.75m is set, the four sides and the top are set as OPEN, i.e. open surface, and the floor is set as Inert, i.e. inert surface.
[0043] Step (2), determine the parameters of the base material EVA and the flame retardant MH, through detection, the density of EVA is 948kg / m3, the ignition point is 237℃, the thermal conductivity is 0.135W / (m*K), the specific heat is 2.3J / g / K, and the average heat release rate is 279.3kW / m2; the density of the flame retardant MH is 2.39kg / m3, the ignition point is 340℃, the thermal conductivity is 0.07W / (m*K), the specific heat is 0.209J / g / K, and the heat absorption rate is 95.6kW / m2; when the mass fraction of the base material EVA and the flame retardant is 400:600, the heat release rate of Formulation Three is 169.1kW / m2; a cotton pad with a length of 50mm, a width of 50mm, and a height of 6mm is placed in the center of the ground, and the ignition point is 156℃; a burner with a diameter of 9.6mm is placed 0.3m above the cotton pad from the floor to simulate a torch; a long strip sample with a length of 130mm, a width of 13mm, and a thickness of 13mm is placed 10mm above the burner, and a square block is arranged on the upper end of the sample with a length of 6mm to simulate a clamp; the experimental environment temperature is set to 25℃, and the relative humidity is 50%.
[0044] Step (3), set the first activation event of the torch, determine the fire supply time of the burner to be 10s, refer to Figure 3 (a) and (b), record the first afterflame time t1 as 0.1s after removing the fire source, which is less than 10s, and the afterflame does not spread to the clamp, refer to Figure 4 (a) and (b) and Figure 5 .
[0045] Step (4), on the basis of step (3), set the second activation event of the torch, set the burner to continue to provide fire for 10 seconds at 10.1 seconds, and remove the fire source at 20.1 seconds. The second afterflame time t2 is 0.1 seconds, the afterflame time t3 is 0.1 seconds, the afterflame plus afterglow time is less than 30s, and the observation experiment phenomenon is that the afterglow afterflame does not spread to the clamp. See Figure 6 (a) and (b), Figure 7 and Figure 8 .
[0046] After the simulation test of the remaining formula (mass ratio of base material to flame retardant 600:400, 500:500) according to the above process, it is obtained through comparative analysis that the single afterflame time of formula 3 is less than 10s, the total afterflame time is less than 50s, and the afterflame plus afterglow time after the second application of flame is less than 30s. The flame retardant grade of the flame retardant is V-0 level.
[0047] The present application considers the error caused by the precision of different sample formulas, and the influence of environmental temperature, humidity and artificial subjective error on the experiment, solves the problems of large workload, complex and tedious experimental period, high cost, high risk coefficient and environmental pollution in the early stage of product development, can quickly screen the formula of the ingredients meeting the flame retardant characteristics, and provides a reference idea for optimizing the performance of the flame retardant material.
[0048] The above-described embodiment is only one embodiment of the present application, which is described in detail, but is not used to limit the scope of the present application. For those skilled in the art, the present application can have various changes and variations. Without departing from the concept of the present application, any modification, equivalent replacement, improvement, etc. is within the protection scope of the present application.
Claims
1. A method of simulating vertical burning of a flame-retardant material, characterized by, The method comprises the following steps: mixing the base material with the flame retardant to form a flame retardant material, performing linear fitting on the heat release rate of the flame retardant material to obtain an average heat release rate, and inputting the parameters of the base material and the flame retardant into a vertical combustion model according to the average heat release rate; setting a first activation event of the torch, running the simulation, and recording the first simulation result; setting a second activation event of the torch, running the simulation, and recording the second simulation result; judging the flame retardant level of the flame retardant material according to the first simulation result and the second simulation result; the parameters of the base material and the flame retardant include density, ignition point, thermal conductivity and specific heat; the first simulation result includes the first afterflame time and afterglow spread; the second simulation result includes the second afterflame time and afterglow time, and whether the afterglow spreads or not; the vertical combustion model is a square open environment with a length of 0.5 m, a width of 0.5 m and a height of 0.75 m, and the four sides and the top are set as open surfaces, and the ground is set as an inert surface; the vertical combustion model is provided with a simulation clamp, a sample material, a simulation torch and a cotton pad.
2. The method according to claim 1, wherein a 50 mm long, 50 mm wide and 6 mm high absorbent cotton sheet is arranged in the center of the ground; an alcohol torch is arranged 0.3 m above the ground above the absorbent cotton sheet, and a long strip sample is arranged 10 mm above the torch; a simulation clamp is arranged 6 mm above the upper end of the sample.
3. The method of claim 2, wherein the vertical burning of the flame retardant material is simulated by: The diameter of the burner is 9.6 0.3 mm.
4. The method of claim 2, wherein the vertical burning of the flame retardant material is simulated by: The long strip sample has a length of 130 mm, a width of 13 mm and a thickness of 13 mm.