Correlation Analysis Between Thermal Conductivity And Pore Characteristics Of Porous Forsterite Material

Forsterite,because of its low thermal conductivity and good compatibility with other refractory,is regarded as a promising component using for preparing the heat insulation material.Molten salt medium as pore-forming agent is used to prepare the porous and light material,then the scientific issue on the correlation between the porosity characteristics and the thermal conductivity is researched.The porous forsterite materials were prepared by magnesium olivine powder as raw material and NaCl salt as pore-forming medium.In order to obtain the materials with different porosity characteristics,the light-weight materials with different contents of NaCl(0wt%,10wt%,20wt%,30wt%,40wt%)are sintered at 1050?,1100? and1150?,respectively.Correlations between porosity characteristics and the thermal conductivity,cold crushing strength of porous forsterite materials based on the grey system theory were researched.Based on the classical thermal conductivity models and the composite heat transfer method,two model of calculating thermal conductivity suitable for porous foreterite materials were established.ANSYS software was used for simulating the porous structure of forsterite and then calculating the thermal conductivities.Results show that:Porous materials synthesized by molten salt media have two fractal features resulted from different pore forming mechanism.The results show that the grey relational degree between the thermal conductivities and the pore size distribution of0.47?4.70?m is greater than that between the thermal conductivities and the other porosity characteristics when the samples are sintered at 1100? with different NaCl contents.And,the correlation coefficient between the thermal conductivities and the pore size distribution of >47.00?m is the greatest when the samples with the same content of NaCl are sintered at different temperatures.Correlation between cold crushing strength and porosity and the number of small aperture is larger than other influence factors.Based on the classical thermal conductivity models and the composite heat transfer theory,this article establishes the thermal conductivity models inaccordance with the porous forsterite materials.ANSYS software is used to establish the finite element model by simulating the micro-structure of porous materials and analyzing the relationships between the thermal conductivity and porosity.Results show that the thermal conductivity decreases with the increase of porosity and the difference between the simulation values and the measured values is much small,confirming the validity of the simulation.