Prediction method of three spontaneous combustion zones in goaf based on RSM and CFD

Abstract

The invention discloses a method for predicting three zones of spontaneous combustion in goaf based on RSM and CFD. The influencing factors of the three-zone distribution include: wind speed v, residual coal thickness T, working face width w, working face height h, residual coal oxygen consumption coefficient k and coal rock average particle size d. Wind speed v, residual coal thickness T, width w and height h are variable factors, and coefficient k and particle size d are invariable factors. The parameter combination of variable factors is designed by RSM and the invariable factors are set to equal values. The three-zone distribution R1 under different combinations of variable factors is calculated by CFD respectively, and the fitting relationship F(v,T,w,h) is obtained by fitting the calculated distribution R1; the parameter combination of invariable factors is designed and the variable factors are set to equal values. The three-zone distribution R2 and (R1-R2) under different combinations of invariable factors are calculated by CFD respectively, and the fitting relationship F(k,d) of the fitting difference (R1-R2) about the invariable factors is obtained; the prediction relationship F(v,T,w,h)-F(k,d) for predicting the three-zone distribution is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine safety, and in particular to a method for predicting three spontaneous combustion zones in goaf areas based on RSM (Response Surface Methodology) and CFD (Computational Fluid Dynamics). Background Art

[0002] Spontaneous combustion of coal in goaf will produce a large amount of toxic and harmful gases and high temperature, which will cause serious harm to the physical and mental health and working environment of underground workers. In serious cases, the working face needs to be closed. Goaf fire prevention and control is often based on the three zones. On the one hand, the position of the oxidation zone in the three zones can guide the minimum advancement speed of the working face. On the other hand, the position of the relevant preventive measures for spontaneous combustion should be placed in the oxidation zone. Therefore, it is of great significance to accurately and quickly obtain the distribution of the three zones of spontaneous combustion in the goaf of the working face for the prevention and control of spontaneous combustion of coal in goaf.

[0003] At present, most of the three zones of spontaneous combustion in goaf are obtained through field measurement methods. The measurement period is long, and the measurement tube and probe are sometimes damaged by the falling coal and rock due to the complex environment of the goaf. In addition, since the three-zone distribution is usually affected by the combined influence of multiple factors including coal itself, geological factors, mining methods and ventilation environment and their changes, the three-zone distribution of different working faces is often different. The three-zone distribution obtained by field measurement is only applicable to the working face currently being measured or studied, and is not applicable to other working faces. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present invention is to propose a prediction method for spontaneous combustion three zones in goaf based on RSM and CFD, which can not only be used to predict the distribution of three zones in goaf, but also can be used to guide the adjustment of the distribution of three zones, and can be applied to different working faces with good versatility.

[0005] According to the goaf spontaneous combustion three-zone prediction method based on RSM and CFD of an embodiment of the present invention, a working face is formed on one side of the goaf adjacent to the coal seam to be mined, and the working face is suitable for arranging coal mining equipment and supports, and the two ends of the working face in the length direction are respectively connected to the air intake lane and the return air lane, and the influencing factors of the three-zone distribution include: the wind speed v in the air intake lane, the thickness T of the residual coal in the goaf, the width w of the working face, the height h of the working face, the oxygen consumption coefficient k of the residual coal in the goaf and the average particle size d of the coal rock in the goaf, the range of the wind speed v is Q1, the range of the residual coal thickness T is Q2, the range of the width w is Q3, the range of the height h is Q4, the range of the residual coal oxygen consumption coefficient k is Q5, and the range of the average particle size d of the coal rock is Q6, and the prediction method includes the following steps:

[0006] S1: Divide the influencing factors into variable factors and immutable factors, wherein the variable factors include the wind speed v, the thickness T of the residual coal, the width w and the height h, and the immutable factors include the oxygen consumption coefficient k of the residual coal and the average particle size d of the coal rock;

[0007] S2: Divide the three zones according to the oxygen concentration in the goaf, the three zones including a cooling zone, an oxidation zone and a suffocation zone, a first boundary line is defined between the cooling zone and the oxidation zone, a second boundary line is defined between the oxidation zone and the suffocation zone, a first position point, a second position point and a third position point are selected on the first boundary line and are spaced apart from each other in sequence, a fourth position point, a fifth position point and a sixth position point are selected on the second boundary line and are spaced apart from each other in sequence, the distances between the first position point, the second position point, the third position point, the fourth position point, the fifth position point and the sixth position point and the working face are r11, r12, r13, r21, r22 and r23 respectively, and r11, r12, r13, r21, r22 and r23 are selected as descriptive parameters of the three-zone distribution;

[0008] S3: According to Q1, Q2, Q3 and Q4, the parameter combination of the variable factors is designed by RSM, and the oxygen consumption coefficient k of the residual coal in the invariable factor is set to the medium value of Q5, and the average particle size d of the coal rock in the invariable factor is set to the medium value of Q6. CFD is used to calculate the three-band distribution R1 under different combinations of variable factors, and the fitting relationship F(v, T, w, h) of the three-band distribution with respect to the variable factors is obtained by fitting the calculated distribution R1 as shown below:

[0009]

[0010] S4: According to Q5 and Q6, the parameter combination of the invariable factors is designed, and the wind speed v in the variable factor is set to the medium value of Q1, the residual coal thickness T in the variable factor is set to the medium value of Q2, the width w in the variable factor is set to the medium value of Q3, and the height h in the variable factor is set to the medium value of Q4. CFD is used to calculate the three-band distribution R2 and the difference (R1-R2) between the distribution R1 and the distribution R2 under different combinations of invariable factors. According to the calculated difference (R1-R2) between the distribution R1 and the distribution R2, the fitting relationship F(k, d) of the difference (R1-R2) between the distribution R1 and the distribution R2 with respect to the invariable factors is obtained by fitting as follows:

[0011]

[0012] S5: Subtract the fitting relationship F(v, T, w, h) obtained in S3 from the fitting relationship F(k, d) obtained in S4 to obtain the prediction relationship F(v, T, w, h)-F(k, d) for predicting the three-band distribution as shown below:

[0013]

[0014] S6: Determine the specific values ​​(v0, T0, w0, h0) of the variable factors (v, T, w, h) of the goaf to be applied, and the specific values ​​(k0, d0) of the immutable factors (k, d), and judge whether to use them to predict the three-band distribution or to guide the adjustment of the three-band distribution. When used to predict the three-band distribution, substitute the values ​​of the variable factors (v0, T0, w0, h0) and the immutable factors (k0, d0) of the goaf to be applied into the prediction relationship F(v, T, w, h)-F(k, d) to obtain F(v0, T0, w0, h0)-F(k0, d0), and calculate the specific values ​​of the descriptive parameters (r11, r12, r13, r21, r22, r23) of the three-band distribution of the goaf through the prediction relationship, thereby obtaining the three-band distribution;

[0015] When used to guide the adjustment of the three-band distribution, first input the specific numerical value of the immutable factor (k, d) and substitute it into the F(k, d) calculation, then input the specific numerical value of the variable factor that you do not want to change and substitute it into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so as to obtain the quantitative relationship between the descriptive parameters (r11, r12, r13, r21, r22, r23) of the three-band distribution of the goaf and the variable factors that you want to change, and adjust the three-band distribution by adjusting the numerical value of the variable factor that you want to change, wherein the variable factor that you want to change can be one or more.

[0016] According to the prediction method for spontaneous combustion three zones in goaf based on RSM and CFD in an embodiment of the present invention, the factors affecting the distribution of spontaneous combustion three zones in goaf are considered separately according to the factors that are artificially variable and immutable, the wind speed v, the thickness of the residual coal T, the width of the working face w and the height of the working face h are divided into variable factors, the oxygen consumption coefficient of the residual coal k and the average particle size d of the coal rock are divided into immutable factors, the distances of multiple position points on the boundary of the oxidation zone from the working face are selected as the description parameters of the three-zone distribution, according to the range of each parameter in the variable factors, RSM is used to design the parameter combination of the variable factors, and CFD is used to calculate the immutable factors. The three-zone distribution R1 of spontaneous combustion in the goaf under the same influencing factors is fitted according to the calculated distribution R1 to obtain the fitting relationship F(v, T, w, h); according to the range of each parameter in the immutable factors, the parameter combination of the immutable factors is designed and the variable factors are set to the same value, and CFD is used to calculate the three-zone distribution R2 and (R1-R2) under different combinations of immutable factors, and the fitting relationship F(k, d) of the fitting difference (R1-R2) about the immutable factors is obtained; finally, the prediction relationship F(v, T, w, h)-F(k, d) for predicting the three-zone distribution is obtained. The prediction method of the embodiment of the present invention can not only be used to quickly and accurately predict the three-zone distribution of the goaf, but also can be used to guide the adjustment of the distribution of the three zones, and can be applied to different working faces, with good versatility.

[0017] In addition, the method for predicting the three zones of spontaneous combustion in goaf based on RSM and CFD according to the embodiment of the present invention may also have the following additional technologies:

[0018] According to one embodiment of the present invention, the first position point and the fourth position point are opposite to the air intake tunnel in a direction parallel to the coal seam mining direction, the third position point and the sixth position point are opposite to the return air tunnel in a direction parallel to the coal seam mining direction, and in a direction parallel to the length extension direction of the working face, the second position point and the fifth position point are both located at the center of the goaf.

[0019] According to one embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the wind speed v, firstly, the specific values ​​of the immutable factors (k, d) are input and brought into F(k, d) calculation, and then the specific values ​​of the variable factors (T, w, h) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0020]

[0021] According to one embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-zone distribution, and the variable factor to be changed is the residual coal thickness T, the specific values ​​of the invariable factors (k, d) are first input and brought into F(k, d) calculation, and then the specific values ​​of the variable factors (v, w, h) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0022]

[0023] According to one embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the width w, firstly, the specific values ​​of the invariable factors (k, d) are input and brought into F(k, d) calculation, and then the specific values ​​of the variable factors (v, T, h) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0024]

[0025] According to one embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the height h, firstly, the specific values ​​of the invariable factors (k, d) are input and brought into F(k, d) calculation, and then the specific values ​​of the variable factors (v, T, w) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0026]

[0027] According to one embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-zone distribution, and the variable factors to be changed are the wind speed v and the residual coal thickness T, the specific values ​​of the invariable factors (k, d) are first input and brought into F(k, d) calculation, and then the specific values ​​of the variable factors (w, h) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0028]

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1 is a schematic diagram of a goaf according to an embodiment of the present invention;

[0032] Figure 2 yes Figure 1 The enlarged view of point A in the middle;

[0033] Figure 3 It is a schematic diagram of the three zones of the goaf;

[0034] Figure 4 is a schematic diagram of a method for predicting three zones of spontaneous combustion in goaf based on RSM and CFD according to an embodiment of the present invention;

[0035] Figure 5 3 is a schematic diagram of the application of the goaf spontaneous combustion three-zone prediction method based on RSM and CFD according to an embodiment of the present invention.

[0036] Reference numerals:

[0037] Goaf 10;

[0038] Cooling zone 11;

[0039] Oxidation zone 12; first boundary line 121; first position point 1211; second position point 1212; third position point 1213;

[0040] The second boundary line 122; the fourth position point 1221; the fifth position point 1222; the sixth position point 1223;

[0041] Choking belt 13;

[0042] Working face 20; air inlet lane 30; return air lane 40. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0044] Reference below Figure 1-Figure 5 A method for predicting the three spontaneous combustion zones of the goaf 10 based on RSM (Response Surface Methodology) and CFD (Computational Fluid Dynamics) according to an embodiment of the present invention is described.

[0045] refer to Figure 1-Figure 3 As shown, a working face 20 is formed on one side of the goaf 10 adjacent to the coal seam to be mined (not shown in the figure), and the working face 20 is suitable for arranging coal mining equipment (not shown in the figure) and a support (not shown in the figure). The two ends of the working face 20 in the length direction are respectively connected to the air inlet lane 30 and the return air lane 40, and the air inlet lane 30, the working face 20 and the return air lane 40 form an air inlet and return channel.

[0046] The factors affecting the three-zone distribution include: wind speed v in the air intake tunnel 30, the thickness T of the coal residue in the goaf 10, the width w of the working face 20, the height h of the working face 20, the oxygen consumption coefficient k of the coal residue in the goaf 10, and the average particle size d of the coal rock in the goaf 10. The range of wind speed v is Q1, the range of the thickness T of the coal residue is Q2, the range of width w is Q3, the range of height h is Q4, the range of oxygen consumption coefficient k of the coal residue is Q5, and the range of average particle size d of the coal rock is Q6. The prediction method includes the following steps:

[0047] S1: The influencing factors are divided into variable factors and immutable factors. The variable factors include the wind speed v, the thickness T, width w and height h of the residual coal. The immutable factors include the oxygen consumption coefficient k of the residual coal and the average particle size d of the coal rock.

[0048] S2: The goaf 10 is divided into three zones according to the oxygen concentration, and the three zones include a cooling zone 11, an oxidation zone 12 and a suffocation zone 13. There is a first boundary line 121 between the cooling zone 11 and the oxidation zone 12, and there is a second boundary line 122 between the oxidation zone 12 and the suffocation zone 13. A first position point 1211, a second position point 1212 and a third position point 1213 spaced apart in sequence are selected on the first boundary line 121, and a fourth position point 1221, a fifth position point 1222 and a sixth position point 1223 spaced apart in sequence are selected on the second boundary line 122. The distances between the first position point 1211, the second position point 1212, the third position point 1213, the fourth position point 1221, the fifth position point 1222 and the sixth position point 1223 and the working face 20 are r11, r12, r13, r21, r22, and r23, respectively. That is, the distance between the first position point 1211 and the working surface 20 is r11, the distance between the second position point 1212 and the working surface 20 is r12, the distance between the third position point 1213 and the working surface 20 is r13, the distance between the fourth position point 1221 and the working surface 20 is r21, the distance between the fifth position point 1222 and the working surface 20 is r22, and the distance between the sixth position point 1223 and the working surface 20 is r23. r11, r12, r13, r21, r22 and r23 are selected as the descriptive parameters of the three-band distribution. That is, by determining the values ​​of r11, r12, r13, r21, r22 and r23, the positions of the first boundary line 121 and the second boundary line 122 of the oxidation zone 12 in the goaf 10 can be determined, thereby determining the three-band distribution of the goaf 10.

[0049] S3: Please refer to Figure 4 According to the range of wind speed v Q1, the range of coal thickness T Q2, the range of width w Q3 and the range of height h Q4, the parameter combination of variable factors is designed by RSM, and the oxygen consumption coefficient k of coal in the invariable factor is set to the medium value of Q5, and the average particle size d of coal rock in the invariable factor is set to the medium value of Q6. CFD is used to calculate the three-band distribution R1 under different combinations of variable factors. According to the calculated distribution R1, the fitting relationship F(v, T, w, h) of the three-band distribution about the variable factors is obtained as follows:

[0050]

[0051] S4: Please continue reading Figure 4According to the range Q5 of the oxygen consumption coefficient k of the residual coal and the range Q6 of the average particle size d of the coal rock, the parameter combination of the invariable factors is designed, and the wind speed v in the variable factor is set to the medium value of Q1, the thickness T of the residual coal in the variable factor is set to the medium value of Q2, the width w in the variable factor is set to the medium value of Q3, and the height h in the variable factor is set to the medium value of Q4. CFD is used to calculate the three-band distribution R2 under different combinations of invariable factors, as well as the difference (R1-R2) between distribution R1 and distribution R2. According to the calculated difference (R1-R2) between distribution R1 and distribution R2, the difference (R1-R2) between distribution R1 and distribution R2 is fitted. The fitting relationship F(k,d) about the invariable factors is as follows:

[0052]

[0053] S5: Please continue reading Figure 4 , subtract the fitting relationship F(v,T,w,h) obtained in S3 from the fitting relationship F(k,d) obtained in S4, and obtain the prediction relationship F(v,T,w,h)-F(k,d) for predicting the three-band distribution as shown below:

[0054]

[0055] S6: Please refer to Figure 5 , determine the specific values ​​(v0, T0, w0, h0) of the variable factors (v, T, w, h) of the goaf 10 to be applied, and the specific values ​​(k0, d0) of the immutable factors (k, d), and judge whether it is used to predict the three-band distribution or to guide the adjustment of the three-band distribution. When used to predict the three-band distribution, the values ​​of the variable factors (v0, T0, w0, h0) and the immutable factors (k0, d0) of the goaf 10 to be applied are substituted into the prediction relationship F(v, T, w, h)-F(k, d) to obtain F(v0, T0, w0, h0)-F(k0, d0), and the specific values ​​of the descriptive parameters (r11, r12, r13, r21, r22, r23) of the three-band distribution of the goaf 10 are calculated by the prediction relationship, thereby obtaining the three-band distribution;

[0056] When used to guide the adjustment of the three-band distribution, first input the specific values ​​of the immutable factors (k, d) and substitute them into the F(k, d) calculation, then input the specific values ​​of the variable factors that you do not want to change and substitute them into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the quantitative relationship between the descriptive parameters (r11, r12, r13, r21, r22, r23) of the three-band distribution of the goaf 10 and the variable factors that you want to change can be obtained, and the three-band distribution can be adjusted by adjusting the values ​​of the variable factors that you want to change, where the variable factors that you want to change can be one or more.

[0057] It should be noted that, in the present application, the “medium value” refers to a value in the middle of a certain range.

[0058] According to the prediction method for the three spontaneous combustion zones of the goaf 10 based on RSM and CFD in the embodiment of the present invention, the factors affecting the distribution of the three spontaneous combustion zones of the goaf 10, which are artificially variable and immutable, are considered separately, the wind speed v, the thickness T of the residual coal, the width w of the working face 20 and the height h of the working face 20 are divided into variable factors, the oxygen consumption coefficient k of the residual coal and the average particle size d of the coal rock are divided into immutable factors, the distances of multiple position points on the boundary of the oxidation zone 12 from the working face 20 are selected as the description parameters of the three-zone distribution, and the parameter combination of the variable factors is designed using RSM according to the range of each parameter in the variable factors, and CFD is used to calculate the distribution of the three spontaneous combustion zones of the goaf 10. FD calculates the spontaneous combustion three-zone distribution R1 of the goaf 10 under different influencing factors, and the fitting relationship F(v, T, w, h) is obtained by fitting the calculated distribution R1; according to the range of each parameter in the immutable factor, the parameter combination of the immutable factor is designed and the variable factor is set to an equal value, and CFD is used to calculate the three-zone distribution R2 and (R1-R2) under different combinations of immutable factors, and the fitting relationship F(k, d) of the fitting difference (R1-R2) about the immutable factor is obtained; finally, the prediction relationship F(v, T, w, h)-F(k, d) for predicting the three-zone distribution is obtained. The prediction method of the embodiment of the present invention can not only be used to quickly and accurately predict the three-zone distribution of the goaf 10, but also can be used to guide the adjustment of the distribution of the three zones, and can be applied to different working faces 20, with good versatility.

[0059] Optionally, see Figure 3 , the first position point 1211 and the fourth position point 1221 are opposite to the air intake tunnel 30 in the direction parallel to the coal seam mining direction, the third position point 1213 and the sixth position point 1223 are opposite to the return air tunnel 40 in the direction parallel to the coal seam mining direction, and the second position point 1212 and the fifth position point 1222 are both located at the center of the goaf 10 in the direction parallel to the length extension direction of the working face 20. In this way, the division of the three-zone distribution of the goaf 10 can be made more accurate.

[0060] In one embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the wind speed v, firstly, the specific values ​​of the invariable factors (k, d) are input and brought into the F(k, d) calculation, and then the specific values ​​of the variable factors (T, w, h) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0061]

[0062] Therefore, based on the above quantitative relationship, the three-zone distribution of the goaf 10 can be adjusted by adjusting the wind speed v.

[0063] In another embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-zone distribution, and the variable factor to be changed is the residual coal thickness T, the specific values ​​of the invariable factors (k, d) are first input and brought into the F(k, d) calculation, and then the specific values ​​of the variable factors (v, w, h) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0064]

[0065] Therefore, based on the above quantitative relationship, the three-zone distribution of the goaf 10 can be adjusted by adjusting the thickness T of the residual coal.

[0066] In another embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the width w, firstly, the specific values ​​of the invariable factors (k, d) are input and substituted into the F(k, d) calculation, and then the specific values ​​of the variable factors (v, T, h) that are not to be changed are input and substituted into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0067]

[0068] Therefore, based on the above quantitative relationship, the three-zone distribution of the goaf 10 can be adjusted by adjusting the width w.

[0069] In another embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the height h, firstly, the specific values ​​of the invariable factors (k, d) are input and substituted into the F(k, d) calculation, and then the specific values ​​of the variable factors (v, T, w) that are not to be changed are input and substituted into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0070]

[0071] Therefore, based on the above quantitative relationship, the three-zone distribution of the goaf 10 can be adjusted by adjusting the height h.

[0072] In one embodiment of the present invention, in S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-zone distribution, and the variable factors to be changed are the wind speed v and the thickness of the coal residue T, the specific values ​​of the invariable factors (k, d) are first input and brought into the F(k, d) calculation, and then the specific values ​​of the variable factors (w, h) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

[0073]

[0074] Therefore, based on the above quantitative relationship, the three-zone distribution of the goaf 10 can be adjusted by adjusting the wind speed v and the thickness T of the residual coal.

[0075] The following takes a specific embodiment as an example to illustrate how to apply the method for predicting the three spontaneous combustion zones of the goaf 10 based on RSM and CFD in the embodiment of the present invention.

[0076] The range Q1 of wind speed v among the variable factors is determined to be 2m / s to 4m / s, the range Q2 of coal thickness T is 0.5m to 1.5m, the range Q3 of width w of working face 20 is 6m to 12m, and the range Q4 of height h of working face 20 is 4m to 6m. The range Q5 of oxygen consumption coefficient k of coal among the invariable factors is 0.0002 to 0.001, and the range Q6 of average particle size d of coal is 0.6m to 1.5m.

[0077] The parameter combinations of variable factors (v, T, w, h) designed by RSM are as follows:

[0078] Serial number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 v 2 4 2 4 3 3 3 3 2 4 2 4 3 3 3 3 2 4 2 4 3 3 3 3 3 T 0.5 0.5 1.5 1.5 1 1 1 1 1 1 1 1 0.5 1.5 0.5 1.5 1 1 1 1 0.5 1.5 0.5 1.5 1 w 9 9 9 9 6 12 6 12 9 9 9 9 6 6 12 12 6 6 12 12 9 9 9 9 9 h 5 5 5 5 4 4 6 6 4 4 6 6 5 5 5 5 5 5 5 5 4 4 6 6 5

[0079] The oxygen consumption coefficient k of the residual coal in the immutable factors is taken as the medium value of Q5, and the average particle size d of the coal rock is taken as the medium value of Q6. The three-band distribution R1 under different combinations of variable factors is calculated, and the fitting relationship F(v, T, w, h) of the fitted three-band R1 with respect to the variable factors is obtained as follows:

[0080]

[0081] The parameter combinations of the design invariant factors (k, d) are as follows:

[0082] Serial number 1 2 3 4 5 6 7 8 9 10 11 12 k 0.0006 0.0006 0.0006 0.0006 0.0002 0.0004 0.0008 0.001 0.0002 0.0004 0.0008 0.001 d 0.6 1.0 1.2 1.5 0.6 0.6 0.6 0.6 0.8 0.8 0.8 0.8 Serial number 13 14 15 16 17 18 19 20 21 22 23 24 k 0.0002 0.0004 0.0008 0.001 0.0002 0.0004 0.0008 0.001 0.0002 0.0004 0.0008 0.001 d 1 1 1 1 1.2 1.2 1.2 1.2 1.5 1.5 1.5 1.5

[0083] The wind speed v in the variable factors is taken as the medium value of Q1, the thickness of the coal residue T is taken as the medium value of Q2, the width w of the working face 20 is taken as the medium value of Q3, and the height h of the working face 20 is taken as the medium value of Q4. The three-band distribution R2 under different combinations of invariable factors is calculated, and the relationship F(k, d) of the difference between R1 and R2 with respect to the invariable factors (k, d) is as follows:

[0084]

[0085] The three-band prediction relationship F(v,T,w,h)-F(k,d) is obtained as follows:

[0086]

[0087] In the application example of the prediction method of the three-zone spontaneous combustion of the goaf 10 based on RSM and CFD, the coal mining working face 20 to be applied is first determined, and then it is determined whether to predict the three-zone distribution of the goaf 10 or to guide the adjustment of the three-zone distribution of the goaf 10. When used to predict the three-zone distribution, the variable factors (v, T, w, h) and the invariable factors (k, d) are respectively input into the calculation values ​​of F (v, T, w, h) and F (k, d), and then F (v, T, w, h) - F (k, d) is calculated to output the specific values ​​of the three zones of the working face 20 to be predicted. For example, inputting v, T, w, h, k and d as 2.4m / s, 1.25m, 8m, 5.7m, 0.0006 and 0.8m respectively can obtain the three-band distributions r11, r12, r13, r21, r22 and r23 as 5.2m, 4.6m, 1.7m, 62.6m, 34.1m and 22.2m respectively.

[0088] When used to guide the adjustment of the three-zone distribution of goaf 10, the input of the immutable factors k0 and d0 is 0.0007 and 1m respectively according to the goaf 10 under study, and the input of the variable factors T0, w0 and h0 that are not desired to be changed is 1m, 8m and 5m respectively, and then it is substituted into F(v,1,8,5)-F(0.0007,1) to obtain:

[0089]

[0090] Based on the above quantitative relationship of F(v,1,8,5)-F(0.0007,1), the “three-band” distribution can be adjusted by adjusting v.

[0091] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0092] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for predicting three spontaneous combustion zones in goaf based on RSM and CFD, characterized in that: A working face is formed on one side of the goaf adjacent to the coal seam to be mined, and the working face is suitable for arranging coal mining equipment and supports. The two ends of the working face in the length direction are respectively connected to the air intake tunnel and the return air tunnel. The influencing factors of the three-zone distribution include: the wind speed v in the air intake tunnel, the thickness T of the residual coal in the goaf, the width w of the working face, the height h of the working face, the oxygen consumption coefficient k of the residual coal in the goaf and the average particle size d of the coal rock in the goaf. The range of the wind speed v is Q1, the range of the residual coal thickness T is Q2, the range of the width w is Q3, the range of the height h is Q4, the range of the residual coal oxygen consumption coefficient k is Q5, and the range of the average particle size d of the coal rock is Q6. The prediction method includes the following steps: S1: Divide the influencing factors into variable factors and immutable factors, wherein the variable factors include the wind speed v, the thickness T of the residual coal, the width w and the height h, and the immutable factors include the oxygen consumption coefficient k of the residual coal and the average particle size d of the coal rock; S2: Divide the three zones according to the oxygen concentration in the goaf, the three zones including a cooling zone, an oxidation zone and a suffocation zone, a first boundary line is defined between the cooling zone and the oxidation zone, a second boundary line is defined between the oxidation zone and the suffocation zone, a first position point, a second position point and a third position point are selected on the first boundary line and are spaced apart from each other in sequence, a fourth position point, a fifth position point and a sixth position point are selected on the second boundary line and are spaced apart from each other in sequence, the distances between the first position point, the second position point, the third position point, the fourth position point, the fifth position point and the sixth position point and the working face are r11, r12, r13, r21, r22 and r23 respectively, and r11, r12, r13, r21, r22 and r23 are selected as descriptive parameters of the three-zone distribution; S3: According to Q1, Q2, Q3 and Q4, the parameter combination of the variable factors is designed by RSM, and the oxygen consumption coefficient k of the residual coal in the invariable factor is set to the medium value of Q5, and the average particle size d of the coal rock in the invariable factor is set to the medium value of Q6. CFD is used to calculate the three-band distribution R1 under different combinations of variable factors, and the fitting relationship F(v, T, w, h) of the three-band distribution with respect to the variable factors is obtained by fitting the calculated distribution R1 as shown below: S4: According to Q5 and Q6, the parameter combination of the invariable factors is designed, and the wind speed v in the variable factor is set to the medium value of Q1, the residual coal thickness T in the variable factor is set to the medium value of Q2, the width w in the variable factor is set to the medium value of Q3, and the height h in the variable factor is set to the medium value of Q4. CFD is used to calculate the three-band distribution R2 and the difference (R1-R2) between the distribution R1 and the distribution R2 under different combinations of invariable factors. According to the calculated difference (R1-R2) between the distribution R1 and the distribution R2, the fitting relationship F(k, d) of the difference (R1-R2) between the distribution R1 and the distribution R2 with respect to the invariable factors is obtained by fitting as follows: S5: Subtract the fitting relationship F(v, T, w, h) obtained in S3 from the fitting relationship F(k, d) obtained in S4 to obtain the prediction relationship F(v, T, w, h)-F(k, d) for predicting the three-band distribution as shown below: S6: Determine the specific values ​​(v0, T0, w0, h0) of the variable factors (v, T, w, h) of the goaf to be applied, and the specific values ​​(k0, d0) of the immutable factors (k, d), and judge whether to use them to predict the three-band distribution or to guide the adjustment of the three-band distribution. When used to predict the three-band distribution, substitute the values ​​of the variable factors (v0, T0, w0, h0) and the immutable factors (k0, d0) of the goaf to be applied into the prediction relationship F(v, T, w, h)-F(k, d) to obtain F(v0, T0, w0, h0)-F(k0, d0), and calculate the specific values ​​of the descriptive parameters (r11, r12, r13, r21, r22, r23) of the three-band distribution of the goaf through the prediction relationship, thereby obtaining the three-band distribution; When used to guide the adjustment of the three-band distribution, first input the specific numerical value of the immutable factor (k, d) and substitute it into the F(k, d) calculation, then input the specific numerical value of the variable factor that you do not want to change and substitute it into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so as to obtain the quantitative relationship between the descriptive parameters (r11, r12, r13, r21, r22, r23) of the three-band distribution of the goaf and the variable factors that you want to change, and adjust the three-band distribution by adjusting the numerical value of the variable factor that you want to change, wherein the variable factor that you want to change can be one or more.

2. The method for predicting three zones of spontaneous combustion in goaf based on RSM and CFD according to claim 1 is characterized in that: The first position point and the fourth position point are opposite to the air intake tunnel in a direction parallel to the coal seam mining direction, the third position point and the sixth position point are opposite to the return air tunnel in a direction parallel to the coal seam mining direction, and the second position point and the fifth position point are both located at the center of the goaf in a direction parallel to the length extension direction of the working face.

3. The method for predicting three spontaneous combustion zones in goaf based on RSM and CFD according to claim 1 is characterized in that: In S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the wind speed v, firstly, the specific value of the immutable factor (k, d) is input and brought into F(k, d) calculation, and then the specific value of the variable factor (T, w, h) that is not to be changed is input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

4. The method for predicting three spontaneous combustion zones in goaf based on RSM and CFD according to claim 1 is characterized in that: In S6, when the prediction relationship F(v,T,w,h)-F(k,d) is used to guide the adjustment of the three-zone distribution, and the variable factor to be changed is the residual coal thickness T, the specific values ​​of the invariable factors (k,d) are first input and brought into F(k,d) calculation, and then the specific values ​​of the variable factors (v,w,h) that are not to be changed are input and brought into the prediction relationship F(v,T,w,h)-F(k,d) calculation, so that the following relationship can be obtained:

5. The method for predicting three zones of spontaneous combustion in goaf based on RSM and CFD according to claim 1 is characterized in that: In S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the width w, firstly, the specific value of the invariable factor (k, d) is input and brought into F(k, d) calculation, and then the specific value of the variable factor (v, T, h) that is not to be changed is input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

6. The method for predicting three spontaneous combustion zones in goaf based on RSM and CFD according to claim 1 is characterized in that: In S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-band distribution, and the variable factor to be changed is the height h, firstly, the specific value of the invariable factor (k, d) is input and brought into F(k, d) calculation, and then the specific value of the variable factor (v, T, w) that is not to be changed is input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

7. The method for predicting three spontaneous combustion zones in goaf based on RSM and CFD according to claim 1 is characterized in that: In S6, when the prediction relationship F(v, T, w, h)-F(k, d) is used to guide the adjustment of the three-zone distribution, and the variable factors to be changed are the wind speed v and the residual coal thickness T, the specific values ​​of the invariable factors (k, d) are first input and brought into the F(k, d) calculation, and then the specific values ​​of the variable factors (w, h) that are not to be changed are input and brought into the prediction relationship F(v, T, w, h)-F(k, d) calculation, so that the following relationship can be obtained:

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