CN105956284A - Method for determining heat conductivity coefficient of compact shaping refractory material - Google Patents

Abstract

The invention belongs to a method for determining the heat conductivity coefficient of a compact shaping refractory material. The method has the technical scheme that the microstructure chart of a compact shaping refractory material sample is obtained through a microscope, and image analysis software is used for carrying out binarization processing and contour line extraction on the microstructure chart to obtain a fractal dimension average value d. An average aperture is used for showing an air hole contour line, the fractal dimension shows the complexity level of the air hole contour line, then, two parameters including the measured fractal dimension and the average aperture can be used for simulating the air hole counter of the compact shaping refractory material, and a physical model is established according to an air hole ratio P. finally, finite element software is used for carrying out the steady-state analysis of a temperature field on the physical model to obtain a temperature gradient, and a formula is used for obtaining a change curve of the heat conductivity coefficient [Lambda]i of the compact shaping refractory material along with temperature Ti. The method has the characteristics of being simple in operation, low in cost and wide in applicability and approaches to practicality.

Description

A kind of method determining fine and close amorphous refractory heat conductivity

Technical field

The invention belongs to Refractory Thermal Conductivity technical field.It is specifically related to a kind of determine fine and close amorphous refractory heat conductivity Method.

Background technology

Fine and close amorphous refractory is the amorphous refractory that true porosity is less than 45%.

The solid phase that fine and close amorphous refractory is made up of polycrystal and vitreous body and the pore with air as medium form.Fine and close setting The solid fraction heat conductivity of refractory material can be obtained by Theoretical Calculation or experiment test, but solid phase and pore are combined and have at random Property so that the heat conductivity of the inorganic material with some pores is difficult to be obtained by Theoretical Calculation.Fine and close amorphous refractory In the distribution of the stomatal properties such as shape of the porosity, pore, the size of pore and pore directly affect fine and close amorphous refractory Heat conductivity, the physical parameter containing leachy fine and close amorphous refractory is obtained by experimental test, but be difficult to obtain physical parameter and Direct mapping relations between temperature, particularly commercial Application furnace lining material is due to the change of production technology so that even if material system Identical and the porosity is close, but there is notable difference in its physical parameter.Originally the thermomechanical property analysis carrying out furnace lining component is only adopted Process with approximation constant so that be on active service the at different temperatures analysis precision of characteristic of furnace lining component exists substantially not enough.

The mensuration of the finest and close amorphous refractory heat conductivity is obtained by test method mostly, National Standard of the People's Republic of China The test method of fine and close amorphous refractory heat conductivity is specified by GB/T 5990-2006.But its test special equipment is held high Expensive, cycle length, costly make difficulty with sample, it is difficult to meet the demand to furnace lining multiple design in reality application.

Summary of the invention

It is contemplated that overcome prior art defect, it is therefore an objective to provide a kind of simple to operate, low cost, the wide and close reality of the suitability The method of determination densification amorphous refractory heat conductivity, the heat conductivity base that the heat conductivity determined by the method records with test This is close.

For achieving the above object, what the technical solution used in the present invention was comprises the concrete steps that:

Step one, according to " refractory material air vent aperture distribution test method " (YB/T118 1997), calculate densification setting fire-resistant The aperture averaging value of material sample

Step 2, obtain the micro-structure diagram of described fine and close amorphous refractory sample with microscope.

Step 3, determine fractal dimension meansigma methods d of fine and close amorphous refractory sample pore

(1) by Image-Pro Plus image analysis software, described micro-structure diagram is carried out binary conversion treatment, obtain at binaryzation Image after reason.

(2) by Image-Pro Plus image analysis software, the image after binary conversion treatment is carried out contour line extraction.

(3) fractal dimension of the contour line extracted is measured by Image-Pro Plus image analysis software, it is thus achieved that fractal dimension is put down Average d.

Step 4, use CAD modeling software construct described aperture averaging valueTake turns with the approximation pore of described fractal dimension meansigma methods d Wide.

Step 5, assume that described approximation pore profile is uniformly distributed, according to the porosity P of described fine and close amorphous refractory sample With described approximation pore profile, set up the physical model of fine and close amorphous refractory sample with CAD modeling software.

Step 6, determine that the physical model of fine and close amorphous refractory sample is in temperature T_iTime heat conductivity λ_i

(1) described physical model is imported in COMSOL Multiphysics finite element software.

(2) with COMSOL Multiphysics finite element software to described physical model grid division.

(3) to the attribute of the fine and close amorphous refractory of COMSOL Multiphysics finite element software input, described fine and close setting is resistance to The attribute of fire material is: set temperature T of physical model_i, the solid fraction in physical model is in temperature T_iTime heat conductivity λ_ai, The air of the air cap in physical model is in temperature T_iTime heat conductivity λ_bi。

(4) with COMSOL Multiphysics finite element software physical model applied boundary condition: set physical model as Hot limit, the heat flow density on hot limit is q；If the opposite side on the hot limit of described physical model is cold limit, the coefficient of heat transfer on cold limit is k.

(5) with COMSOL Multiphysics finite element software, physical model is carried out Temperature calculating, obtain the hot limit of physical model Mean temperature T_HiMean temperature T on limit cold with physical model_Ci。

(6) physical model is in temperature T_iTime heat conductivity λ_i

${\mathrm{\λ}}_i=-q/\frac{{\mathrm{dT}}_i}{dx}\mathrm{...}\left(1\right)$

Formula (1): dT₁Represent hot limit mean temperature T_HiWith the difference of cold limit mean temperature, K；

Dx represents the distance on the fine and close hot limit of amorphous refractory sample and cold limit, m；

Q represents the heat flow density on hot limit, W/m²；

I represents 1 ... the natural number of n, and n is arbitrary natural number in 5～10.

Step 7, according to step 6 (3)-(6), obtain fine and close amorphous refractory in temperature T₁.T₂.T₃…T_nTime corresponding leading Hot coefficient lambda₁.λ₂.λ₃…λ_n。

Draw the curve that fine and close amorphous refractory heat conductivity varies with temperature.

Described fine and close amorphous refractory is the amorphous refractory that true porosity is less than 45%.

Owing to using technique scheme, the present invention compared with prior art has a following good effect:

First, the present invention has only to be obtained the micro-structure diagram of fine and close amorphous refractory sample by microscope, according to described micro- The feature of structure chart, the fine and close amorphous refractory pore profile of simulation on computers also sets up physical model, really according to porosity P Its heat conductivity fixed.And the measurement of heat-pole method is sample to be heated in stove set point of temperature and is incubated, then with along specimen length direction Burying line-like electrical conductors in the sample to carry out locally heating, thermocouple just starts to measure temperature rise over time, and this temperature rise is in time Function be exactly the heat conductivity of tested sample.The present invention is simpler compared to heat-pole method operation and cost is lower.

Secondly, the present invention, for replacing real pore profile, utilizes fractal dimension to represent the complexity of pore profile.Then use Fractal dimension and pore size construct approximation pore profile, then the densification setting with the approximation different porosity P of pore profile foundation is resistance to The physical model of fire material sample.The most applicable to the fine and close amorphous refractory of various porosity P.Compared to additive method: flat board The Applicable temperature scope of method is the highest, and the temperature of general hot side maintains about 1000 DEG C；Laser method is for measuring leading of dense material Hot coefficient and a kind of method of setting up, be used for measuring the heat conductivity of dense material；Therefore the method applicability of the present invention is wider.

For porosity refractory material below 45%, the result that the heat conductivity result that this method measures records with experiment accords with substantially Close.

Therefore, to have simple to operate, low cost, the suitability wide and substantially close to actual feature for the present invention.

Accompanying drawing explanation

Fig. 1 is the micro-structure diagram of present invention high alumina refractories sample to be determined；

Fig. 2 is the image after the binary conversion treatment of micro-structure diagram shown in Fig. 1；

Fig. 3 is the pore contour line extraction figure of the image shown in Fig. 2；

Fig. 4 is the approximation pore profile diagram of sample shown in Fig. 1；

Fig. 5 is the physical model of sample shown in Fig. 1；

Fig. 6 is to the image after the physical model grid division shown in Fig. 5；

Fig. 7 is the Calculated Results of Temperature Field figure to physical model shown in Fig. 5；

Fig. 8 is the curve chart that the heat conductivity of sample shown in Fig. 1 varies with temperature；

Fig. 9 is the curve chart that the heat conductivity of forsterite refractory varies with temperature；

Figure 10 is the comparison diagram that present invention determine that value and test measured value of sample heat conductivity shown in Fig. 1；

Figure 11 is the comparison diagram that present invention determine that value and test measured value of forsterite refractory heat conductivity.

Detailed description of the invention

The present invention will be further described with detailed description of the invention below in conjunction with the accompanying drawings, not the restriction to its protection domain:

Embodiment 1

A kind of method determining fine and close amorphous refractory heat conductivity.Comprising the concrete steps that of method described in the present embodiment:

Described in the present embodiment, fine and close amorphous refractory is high alumina refractories, and the described high alumina refractories porosity is 29.3%.

Step one, according to " refractory material air vent aperture distribution test method " (YB/T118 1997), calculate described High-Alumina resistance to The aperture averaging value of fire material sampleAperture averaging value

Step 2, with microscope obtain described high alumina refractories sample micro-structure diagram, micro-structure diagram is as shown in Figure 1.

Step 3, determine fractal dimension meansigma methods d of high alumina refractories sample pore

(1) by Image-Pro Plus image analysis software, described micro-structure diagram is carried out binary conversion treatment, obtain such as Fig. 2 institute Image after the binary conversion treatment shown.

(2) by Image-Pro Plus image analysis software, the image after binary conversion treatment is carried out contour line extraction, extracted Contour line is as shown in Figure 3.

(3) fractal dimension of the contour line extracted is measured by Image-Pro Plus image analysis software, it is thus achieved that fractal dimension is put down Average is 1.201.

Step 4, as shown in Figure 4, constructing described aperture averaging value with CAD modeling software is 1.48mm and described fractal dimension Meansigma methods is the approximation pore profile of 1.201.

Step 5, assume approximate pore profile be uniformly distributed, be 29.3% according to the porosity P of described high alumina refractories sample With described approximation pore profile, set up the physical model of high alumina refractories sample as shown in Figure 5 with CAD modeling software.

Step 6, determine that the physical model of high alumina refractories sample is in temperature T₁Time heat conductivity λ₁

(1) described physical model is imported in COMSOL Multiphysics finite element software.

(2) as shown in Figure 6, with COMSOL Multiphysics finite element software to described physical model grid division.

(3) to the attribute of COMSOL Multiphysics finite element software input high alumina refractories, described High-Alumina fire proofed wood The attribute of material is: set temperature T of physical model₁Being 350 DEG C (623.15K), the solid fraction in physical model is in temperature T₁For Heat conductivity λ time 350 DEG C (623.15K)_a1For 2.38W/ (m K), the air of the air cap in physical model is in temperature T₁ It is heat conductivity λ time 350 DEG C (623.15K)_b1For 0.03W/ (m K).

(4) with COMSOL Multiphysics finite element software physical model applied boundary condition: set physical model as Hot limit, heat flow density q on hot limit is 5000W/m²；If the opposite side on the hot limit of described physical model is cold limit, the coefficient of heat transfer on cold limit K is 500W/ (m²·K)。

(5) with COMSOL Multiphysics finite element software, physical model being carried out Temperature calculating, Calculated Results of Temperature Field is such as Shown in Fig. 7, obtain mean temperature T on the hot limit of physical model_H1It is the average of 407.79 DEG C (680.94K) and the cold limit of physical model Temperature T_C1It is 359.91 DEG C (633.06K).

(6) physical model is in temperature T₁It is heat conductivity λ time 350 DEG C (623.15K)₁

${\mathrm{\λ}}_1=-q/\frac{{\mathrm{dT}}_1}{dx}\mathrm{...}\left(1\right)$

Formula (1): dT₁Represent hot limit mean temperature T_H1With cold limit mean temperature T_C1Difference, dT₁For-47.88K；

Dx represents the distance on the hot limit of high alumina refractories sample and cold limit, and dx is 0.01m；

Q represents the heat flow density on hot limit；Q is 5000W/m²。

By formula (1)

λ₁=1.04W/ (m K)

Step 7, according to step 6 (3)-(7), obtain high alumina refractories in temperature T₂It is 500 DEG C of (773.15K), T₃ It is 700 DEG C of (973.15K), T₄It is 900 DEG C (1173.15K) and T₅Heat conduction system corresponding when being 1100 DEG C (1373.15K) Number λ₂For 0.96W/ (m K), λ₃For 0.94W/ (m K), λ₄For 0.98W/ (m K) and λ₅For 1.01W/ (m K).

Obtain the curve chart that heat conductivity as shown in Figure 8 varies with temperature, i.e. obtain the heat conductivity of high alumina refractories.

Embodiment 2

A kind of method determining fine and close amorphous refractory heat conductivity.Comprising the concrete steps that of method described in the present embodiment:

Described in the present embodiment, fine and close amorphous refractory is forsterite refractory, and the described forsterite refractory porosity is 42.0%.

Step one, according to " refractory material air vent aperture distribution test method " (YB/T118 1997), calculate described forsterite The aperture averaging value of refractory material sampleAperture averaging value

Step 2, with microscope obtain described forsterite refractory sample micro-structure diagram.

Step 3, determine fractal dimension meansigma methods d of forsterite refractory sample pore

(1) by Image-Pro Plus image analysis software, described micro-structure diagram is carried out binary conversion treatment, obtain at binaryzation Image after reason.

(2) by Image-Pro Plus image analysis software, the image after binary conversion treatment is carried out contour line extraction.

(3) fractal dimension of the contour line extracted is measured by Image-Pro Plus image analysis software, it is thus achieved that fractal dimension is put down Average is 1.165.

Step 4, construct described aperture averaging value with CAD modeling software and be 43.6 μm and described fractal dimension meansigma methods is 1.165 Approximation pore profile.

Step 5, assume approximate pore profile be uniformly distributed, be 42.0% according to the porosity P of described forsterite refractory sample With described approximation pore profile, set up the physical model of forsterite refractory sample with CAD modeling software.

Step 6, determine that the physical model of forsterite refractory sample is in temperature T₁Time heat conductivity λ₁

(1) described physical model is imported in COMSOL Multiphysics finite element software.

(2) with COMSOL Multiphysics finite element software to described physical model grid division.

(3) to the attribute of COMSOL Multiphysics finite element software input forsterite refractory, described forsterite is resistance to The attribute of fire material is: set temperature T of physical model₁Being 350 DEG C (623.15K), the solid fraction in physical model is in temperature T₁It is heat conductivity λ time 350 DEG C (623.15K)_a1For 4.20W/ (m K), the air of the air cap in physical model exists Temperature T₁It is heat conductivity λ time 350 DEG C (623.15K)_b1For 0.03W/ (m K).

(4) with COMSOL Multiphysics finite element software physical model applied boundary condition: set physical model as Hot limit, heat flow density q on hot limit is 5000W/m²；If the opposite side on the hot limit of described physical model is cold limit, the coefficient of heat transfer on cold limit K is 500W/ (m²·K)。

(5) with COMSOL Multiphysics finite element software, physical model is carried out Temperature calculating, obtain the hot limit of physical model Mean temperature T_H1It is 439.70 DEG C (712.85K) and mean temperature T of cold limit physical model_C1It is 364.29 DEG C (637.44K).

(6) physical model is in temperature T₁It is heat conductivity λ time 350 (623.15K) DEG C₁

${\mathrm{\λ}}_1=-q/\frac{{\mathrm{dT}}_1}{dx}\mathrm{...}\left(1\right)$

Formula (1): dT₁Represent hot limit mean temperature T_H1With cold limit mean temperature T_C1Difference, dT₁For-75.41K；

Dx represents the distance on the hot limit of forsterite refractory sample and cold limit, and dx is 0.01m；

Q represents the heat flow density on hot limit；Q is 5000W/m²。

By formula (1)

λ₁=0.663W/ (m K)

Step 7, according to step 6 (3)-(7), obtain forsterite refractory in temperature T₂Be 400 DEG C (673.15K), T₃It is 500 DEG C of (773.15K), T₄It is 600 DEG C of (873.15K), T₅It is 700 DEG C of (973.15K), T₆Be 800 DEG C (1073.15K), T₇It is 900 DEG C of (1173.15K), T₈It is 1000 DEG C of (1273.15K), T₉It is 1100 DEG C (1373.15K) and T₁₀It it is 1200 DEG C (1473.15K) heat conductivity λ corresponding time₂For 0.684W/ (m K), λ₃For 0.712W/ (m K), λ₄For 0.748W/(m·K)、λ₅For 0.784W/ (m K), λ₆For 0.810W/ (m K), λ₇For 0.831W/ (m K), λ₈For 0.853W/(m·K)、λ₉For 0.875W/ (m K) and λ₁₀For 0.907W/ (m K).

Obtain the curve chart that heat conductivity as shown in Figure 9 varies with temperature, i.e. obtain the heat conductivity of forsterite refractory.

This detailed description of the invention compared with prior art has a following good effect:

First, this detailed description of the invention has only to be obtained the micro-structure diagram of fine and close amorphous refractory sample by microscope, according to The feature of described micro-structure diagram, the fine and close amorphous refractory pore profile of simulation on computers also sets up physics according to porosity P Model, determines its heat conductivity.And the measurement of heat-pole method is sample to be heated in stove set point of temperature and is incubated, then with along sample Length direction buries line-like electrical conductors in the sample to carry out locally heating, and thermocouple just starts to measure temperature rise over time, this temperature Rise the heat conductivity that function in time is exactly tested sample.This detailed description of the invention operates simpler and cost compared to heat-pole method Lower.

Secondly, this detailed description of the invention, for replacing real pore profile, utilizes fractal dimension to represent the complexity of pore profile. Then construct approximation pore profile with fractal dimension and pore size, then set up the densification of different porosity P with approximation pore profile The physical model of amorphous refractory sample, the most applicable to the fine and close amorphous refractory of various porosity P.Compared to additive method: The Applicable temperature scope of flat band method is the highest, and the temperature of general hot side maintains about 1000 DEG C；Laser method is for measuring dense material Heat conductivity and a kind of method of setting up, be used for measuring the heat conductivity of dense material；Therefore the side of this detailed description of the invention The method suitability is wider.

For porosity refractory material below 45%, the heat conduction system that the heat conductivity that this detailed description of the invention determines records with test Number as shown in Figure 10 and Figure 11, both results substantially close to.

Therefore, to have simple to operate, low cost, the suitability wide and substantially close to actual feature for this detailed description of the invention.

Claims (2)

1. the method determining fine and close amorphous refractory heat conductivity, it is characterised in that comprising the concrete steps that of described method:

Step one, " refractory material air vent aperture distribution test method " according to YB/T118 1997, calculate densification setting fire-resistant The aperture averaging value of material sample

Step 2, obtain the micro-structure diagram of described fine and close amorphous refractory sample with microscope；

Step 3, determine fractal dimension meansigma methods d of fine and close amorphous refractory sample pore

(1) by Image-Pro Plus image analysis software, described micro-structure diagram is carried out binary conversion treatment, obtain at binaryzation Image after reason；

(2) by Image-Pro Plus image analysis software, the image after binary conversion treatment is carried out contour line extraction；

(3) fractal dimension of the contour line extracted is measured by Image-Pro Plus image analysis software, it is thus achieved that fractal dimension is put down Average d；

Step 4, use CAD modeling software construct described aperture averaging valueTake turns with the approximation pore of described fractal dimension meansigma methods d Wide；

Step 5, assume that described approximation pore profile is uniformly distributed, according to the porosity P of described fine and close amorphous refractory sample With described approximation pore profile, set up the physical model of fine and close amorphous refractory sample with CAD modeling software；

Step 6, determine that the physical model of fine and close amorphous refractory sample is in temperature T_iTime heat conductivity λ_i

(1) described physical model is imported in COMSOL Multiphysics finite element software；

(2) with COMSOL Multiphysics finite element software to described physical model grid division；

(3) to the attribute of the fine and close amorphous refractory of COMSOL Multiphysics finite element software input, described fine and close setting is resistance to The attribute of fire material is: set temperature T of physical model_i, the solid fraction in physical model is in temperature T_iTime heat conductivity λ_ai, The air of the air cap in physical model is in temperature T_iTime heat conductivity λ_bi；

(4) with COMSOL Multiphysics finite element software physical model applied boundary condition: set physical model as Hot limit, the heat flow density on hot limit is q；If the opposite side on the hot limit of described physical model is cold limit, the coefficient of heat transfer on cold limit is k；

(5) with COMSOL Multiphysics finite element software, physical model is carried out Temperature calculating, obtain the hot limit of physical model Mean temperature T_HiMean temperature T on limit cold with physical model_Ci；

(6) physical model is in temperature T_iTime heat conductivity λ_i

${\mathrm{\λ}}_i=-q/\frac{{\mathrm{dT}}_i}{dx}...\left(1\right)$

Formula (1): dT₁Represent hot limit mean temperature T_HiWith cold limit mean temperature T_CiDifference, K,

Dx represents the distance on the fine and close hot limit of amorphous refractory sample and cold limit, m,

Q represents the heat flow density on hot limit, W/m²,

I represents 1 ... the natural number of n, and n is arbitrary natural number in 5～10；

Step 7, according to step 6 (3)-(6), obtain fine and close amorphous refractory in temperature T₁.T₂.T₃…T_nTime corresponding leading Hot coefficient lambda₁.λ₂.λ₃…λ_n；

Draw the curve that fine and close amorphous refractory heat conductivity varies with temperature.

The method determining fine and close amorphous refractory heat conductivity the most according to claim 1, it is characterised in that described densification is fixed Shape refractory material is the amorphous refractory that true porosity is less than 45%.