基于相似性原则的橡胶颗粒-砂混合物热导率理论模型

Theoretical model for thermal conductivity of rubber-sand mixtures based on similarity heat conduction principle

为准确定量评价人工隔热材料橡胶颗粒-砂混合物的导热性能,突破现有经验关系模型适用性较差的局限性,以Wiener土体热导率模型为框架,基于相似性原则,通过对混合物中各介质的导热性能进行分析,建立用于计算混合物热导率的理论模型,分析模型中计算参数的意义和确定方法,根据文献报道热导率测试数据,对比验证模型的有效性,并探讨模型进一步完善和拓展的研究方向。研究结果表明:橡胶颗粒和孔隙液的导热能力相似,可将两者归属为相似类传热介质应用于Wiener串、并联模型中;模型综合考虑了橡胶掺量、粒径比、饱和度和孔隙率等对橡胶颗粒-砂混合物结构和导热性能的影响,准确描述了混合物热导率和橡胶掺量、粒径比的相关关系,与实测数据的对比结果显示了较高的精确度。探明复杂应力状态和极端气候条件对刚-柔性颗粒混合物导热性能的作用规律,是进一步完善和拓展本文模型的重要研究内容。

The aims of this study are to quantitatively assess the thermal conductivity of the artificial rubber particles-sand mixtures and to break through the limited applicability of the current empirical models.Based on the Wiener model and similarity principle,the thermal conductivity of each constitute in the mixtures is analyzed,and a theoretical model for calculating the thermal conductivity of the mixtures is developed.The meaning and the determination method of each parameter in the new model are investigated.The validity of this new model is verified throgh the thermal conductivity data derived from the existing literatures,and further lines of inquiry for the thermal conductivity model are discussed and suggested.The results indicate that the rubber particles process comparable thermal-transmission capacity to the pore water within the rubber-sand mixtures.Therefore,they can be categorized as similar thermal transfer medium when applied in either series or parallel Wiener models.The new model systematically consider the influences of rubber content,particle size ratio,saturation level and porosity on the structure and the thermal conduction capacity of the rubber-sand mixtures.It accurately describes the relationship between the thermal conductivity of the mixtures and either the rubber content or the particle size ratio,and shows high accuracy to the measured data results.Exploring the effects of complex stress state and the extreme climatic conditions on thermal conduction property of the rigid-soft granular particle mixtures is suggested important for further investigating and improving the proposed new model.