TANG Shaorong 1 ，2 ，3 ， YIN Lei1 ，YANG Qiang1 ， KE Dexiu1
(1. College of Civil and Hydraulic Engineering，Ningxia University，Yinchuan 750021，China;2. Ningxia Research Center of Technology on Water-saving Irrigation and Water Resources Regulation，Ningxia University，Yinchuan 750021，China;3. Engineering Research Center forEfficient Utilization of Water Resources in Modern Agricultureon Arid Regions，Ningxia University，Yinchuan 750021，China)
Abstract
Objective In order to accurately analyze the temperature field of the drainage base of the pulverized sandy soil layer improved by microcapsule phase change materials(mPCM)，it is necessary to investigate the thermal conductivity of the pulverized sandy soil improved by microcapsule phase change materials and to establish a prediction model.
Methods The research focuses on a specific region of Ningxia canal-based silt sandy soil. Firstly，mPCM was used as an ameliorant to prepare mPCM-amended silt sandy soil. The thermal conductivity and internal structure of the prepared soil were tested usinganelectronmicroscopescanning. Next，apredictionmodelforthermalconductivitywasestablishedusingmultivariatelin⁃ ear regression and support vector machine(SVM)methods.
Results and Discussion The thermal conductivity of silt sand amended with mPCM was observed to be influenced by the test temperature and the phase transition temperature of the mPCM. Notably，the thermal conductivity demonstrated a pronounced temperature dependency，characterized by three distinct phases:a rapid decrease(-10 to 0 °C)，a slow decrease(0 to 5 °C)， and a gradual increase(5 to 10 °C). Furthermore，the coefficient of thermal conductivity of mPCM-amended silt loam exceeded that of unamended silt loam and exhibited augmentation with increasing water content，dry density，and mPCM mass fraction. Both multiple linear regression and Support Vector Machine(SVM)models effectively predicted the thermal conductivity of mPCM-amended silt loam. Nevertheless，the SVM model proved to be more adept at capturing the nonlinear relationship among the influencing factors of thermal conductivity in mPCM-amended silt loam.
Conclusion The thermal conductivity of mPCM-amended silty sand soil is influenced by several key factors，including water content，dry density，and mPCM content. Furthermore，it is significantly impacted by the relative proportions of ice and water， the latent heat of phase change for ice and water，the latent heat of phase change of mPCM，as well as the role of mPCM filling and densification. These factors exhibit notable temperature-dependent effects. For accurate prediction of thermal conductivity， the SVM model proves to be effective. The findings of this study can provide valuable insights for the application and exploration of phase change materials in regions characterized by seasonal permafrost.
Keywords:microencapsulated phase change material;silty sand;thermal conductivity;predictive modeling;multiple linear regression;support vector machine
Get Citation:TANG S R，YIN L，YANG Q，et al. Thermal conductivity and predictive modeling of microencapsulated phase change materials for improved silt sands[J]. China Powder Science and Technology，2024，30(3):112−123.
Received:2024-11-09.Revised:2024-04-15,Online:2024-04-25。
Funding Project:国家自然科学基金项目，编号:52368050;宁夏回族自治区重点研发计划项目，编号:2021BEG03023;宁夏高等学校一流学科
建设项目，编号:NXYLXK2021A03;宁夏大学学生创新创业训练项目，编号:202310749586。
First Author: 唐少容(1982—)，女，副教授，博士，硕士生导师，研究方向为岩土工程。E-mail:tangsrong@126. com。
DOI：10.13732/j.issn.1008-5548.2024.03.010
CLC No:TB4;TU445 Type Code:A
Serial No:1008-5548（2024）03-0112-12
