| Manual labor was replaced by machines since the first industrial revolution.While the use of machinery and equipment facilitates people’s production and life,it also generates various noises.Studies have shown that noise pollution can interfere with emotions,reduce industrial production efficiency,damage hearing,and even threaten human health.The foam glass ceramics sound-absorbing material has the characteristics of broadband sound absorption,convenient installation and large-scale manufacturing and low cost,and has great application potential in the field of sound absorption and noise reduction.The foam glass ceramics is usually prepared from industrial waste.The silicon dioxide,calcium oxide and aluminum oxide in the high-titanium blast furnace slag are the main components of glass,the high content of titanium dioxide is a high-quality crystal nucleating agent,such composition have advantages in the preparation of foam glass ceramics.In addition,the use of high-titanium blast furnace slag to prepare sound-absorbing material for foam glass ceramics reduces environmental pollution.It also reduces production costs,and can also make full use of the titanium resources,which has important environmental protection significance and is in line with sustainable development.Foam glass ceramics sound absorption material is prepared form slow-cooling high-titanium blast furnace slag in the previous research,result shows that its high-efficiency sound absorption frequency is wide(800-2300Hz),and its efficient sound absorption frequency and traffic noise frequency(250-2000Hz)is more consistent and can be used as a sound-absorbing material for traffic road network sound barriers.In order to efficiently prepare the foam glass ceramic with excellent sound absorption performance,achieve the design of the sound-absorbing structure of the foam glass ceramic and adjust the sound absorption performance,for which establish a sound absorption model is an effective way.In addition,the sound absorption model can help clarify the physical nature of the sound absorption process and make a foundation for revealing its sound absorption mechanism.This article uses slow-cooling high-titanium blast furnace slag and waste glass powder as the main raw materials,supplemented by Al N,Na2B4O7·10H2O,and adopts the "one-step sintering method" to prepare foam glass ceramics with different pore structures.Observe the microscopic morphology of the foam glass ceramics sound-absorbing material by SEM;use XRD to analyze the material phase,Jade calculates its crystallinity,and use a rheometer and automatic true density analyzer to obtain the flow resistance and open porosity of the foam glass ceramics;Calculate the average pore size of the foam glass ceramics by SEM-Image J.By studying the influence of average pore size,open porosity and crystallinity on the sound absorption performance of foam glass ceramics,it provides a basis for the refinement and value of structural factors in the sound absorption model;In addition,based on the theoretical sound absorption model,using the porosity and average pore size of the foam glass ceramics as parameters,the calculated values of the model are compared with the measured values,and then the theoretical model of the foam glass ceramics is established by modifying the structural factors;Based on the Delany-Bazley empirical model,using the flow resistance of the foam glass ceramics as a parameter,the calculated value of the model is compared with the measured value to verify the accuracy of the Delany-Bazley empirical model in the foam glass ceramics;based on Johnson-Allard’s semi-experience model,taking the flow resistance and porosity of the foam glass ceramics as parameters,compares the calculated values of the model with the measured values,and then establishes a semi-empirical model of the foam glass ceramics by modifying the structural factors.The main conclusions are as follows:The foam glass ceramic prepared with slow cooling high-titanium blast furnace slag has poor roundness of pore structure,and as the average pore size increases,more connected pores appear,and the difference between the largest and smallest pores get bigger;The activation energy of crystallization of foam glass ceramics is300.04KJ/mol,which is easy to overcome this energy barrier and crystallize,microcrystals of different sizes are attached to the wall of the hole,which together form a complex and specific micro structure;By calculating its average sound absorption factor,the value is in the range of 0.30-0.38,which is a sound-absorbing material;its high-efficiency sound-absorbing frequency range is 1000-1600 Hz,which can effectively absorb traffic noise in this frequency range;in addition,,the foam glass ceramics also has a good sound absorption performance at f>4000Hz;When the open porosity is 63%-78%,the average pore diameter is 0.16-0.32 mm and the crystallinity is 25%-33%,the average sound absorption factor of the foam glass ceramic first increase and then decrease with the increases of average pore diameter and open porosity,and increase with the increase of crystallinity;by studying the influence of micro structure(average pore size,open porosity and crystallinity)on its sound absorption performance,the result shows that crystallinity has the greatest influence on sound absorption characteristics.Porosity is second,and the influence of average pore diameter is relatively small.Taking the porosity and average pore diameter of the foam glass ceramics as the experimental data,3,5and8 as value of structure factors to calculate the theoretical sound absorption model,and comparing the calculated value with the measured value,the result shows: when the structure factor is 3-8,the calculated value is closer to the spectrum curve of the measured value with the value of the structure factor increases.The complex and specific pore structure of the foam glass ceramic makes the result still cannot accurately reflect the sound absorption performance of the foam glass ceramics when the structure factor value is 8.Therefore,starting from the microstructure of the foam glass ceramic,by studying the influence of the microstructure parameters on the sound absorption performance,the structural factors are refined and assignment,and the modified structure factor is calculated and analyzed again.The results show that the absolute error of the calculated value obtained from the modified structure factor at f=125-2500 Hz is relatively small,and it’s first characteristic peak of the material is accurately calculated,which can be used for the sound absorption structure design of sound-absorbing materials for sound barriers in traffic road networks;but the absolute error between the calculated value and the measured value varies at f>3000Hz,the frequency spectrum curve does not match the sound absorption characteristics of foam glass ceramics.The flow resistance rate of the foam glass ceramic is used as the experimental data,and the Delany-Bazley empirical model is calculated.The results show that the calculated spectrum curve is less consistent with the measured value,and it is not suitable for predicting the sound absorption performance of the glass-ceramic foam glass.Taking the porosity and flow resistance rate of the foam glass ceramics as the experimental data,the Johnson-Allard semi-empirical model was calculated with 3,5,and 8 different value of structure factors.The results show that: with the value of the structure factor increases,The similarity between the calculated value spectrum curve and the measured value spectrum curve gradually increases;when the structure factor gradually rises to 8,the error between the calculated value and the measured value is still relatively large,which can’t accurately reflect the sound absorption performance of the foam glass ceramics;by calculating and analyzing the modified structure factor again,the semi-empirical sound absorption model can better predict the sound absorption performance of the foam glass ceramics.The positions of the first characteristic peaks of the sound-absorbing materials are almost the same,there is a good agreement in the high frequency range,this model can calculate the sound absorption factor in the full frequency band of 125-6300 Hz.Both the theoretical model and the semi-empirical model of the foam glass ceramic can predict the sound absorption performance in the high-efficiency sound absorption frequency band(1000-1600Hz).The absolute error at 1000Hz、1250Hz、1600Hz is used to compare and analyze the accuracy of the theoretical model and the semi-empirical model on the high-efficiency sound absorption frequency band.The results show that the accuracy of the theoretical sound model is higher than that of the semi-empirical sound absorption model. |
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