随着航天器空间探测需求的提高，要求热控技术具备更高的控制精度和响应速度。为应对这种需求，本文提出一种热智能材料技术，其热导率在电场调控下发生显著变化，可实现对被控对象与外界热传导的自主调控。该热智能材料是一种纳米颗粒悬浮液，本文采用布朗动力学模拟和实验的方法对纳米颗粒悬浮液的导热调控规律、悬浮液中纳米粒子定向性调控以及电场作用下悬浮液热导率测试方面开展了研究工作。在Nan模型的基础上，采用先后计算颗粒团聚体热导率和材料整体热导率的两步方法，针对通过外场调控的纳米颗粒悬浮液建立了新的热导率模型。计算分析表明，外场作用下形成的纳米颗粒团聚体有助于悬浮液热导率的提升，团聚体的固定取向可进一步增加热导率的调控范围。制备纳米颗粒悬浮液时需选用异形程度大的高导热纳米颗粒，新模型预测外场对高导热石墨片悬浮液的热导率调控范围可达10~40倍。建立棒状颗粒的极化模型，采用布朗动力学模拟观察棒状纳米颗粒的二维运动和微观聚集结构形成过程。结果表明，单个棒状纳米颗粒旋转至电场方向所需时间为毫秒量级，纳米颗粒与电场方向的初始角度越大，所需的时间越长；两颗粒体系最终形成首尾相接和搭接两种类型的结构；壁面对颗粒产生吸引作用，颗粒轴向最终垂直于壁面。在电场作用下，棒状颗粒在悬浮液中形成链状结构，随着颗粒体积分数的增加，颗粒最终形成的链状结构越长。当纳米颗粒体积分数为6%时，微观聚集结构中的长链相互影响，形成较复杂的树枝状结构。通过三步法制备了GNS / LDH-硅油悬浮液和C/GNS-硅油悬浮液两种热智能材料。利用高速相机记录材料微观结构的形成过程，结果表明电场强度越大，热智能材料的链状结构越显著。通过激光闪光法测量材料热导率，对于GNS / LDH热智能材料，其热导率随电场强度的增大而增大，相对于基液热导率的最大增幅为50%，并且导热性能调控具有可逆性，调控幅度为128%。对于C/GNS热智能材料，在电场强度小于400 V/mm时，悬浮液热导率的增长幅度随电场强度的增加而增加，最大增长幅度为11.6%。

With the increasing demands of space exploration, thermal control technology with higher control accuracy and response speed is highly desired. In order to meet the demand, this thesis proposes a kind of thermal smart material technology. The thermal conductivity of thermal smart material changes significantly under the control of electric field, and it can realize the autonomous regulation of the heat conduction between the controlled object and the outside surrounding. In this thesis，the thermal conductivity of thermal smart materials and orientation behavior of nanoparticles in suspension controlled by electric field were systematically investigated, and the thermal conductivity of thermal smart materials was measured.Based on the Nan’s model, a new thermal conductivity prediction model for nanoparticle suspensions was proposed by a two-step method. The first step is to calculate the thermal conductivity of particle agglomerates, and the second step is to calculate the overall thermal conductivity of the material. The calculation and analysis show that the nanoparticle agglomerates driven by the external field contribute to the increase of the thermal conductivity of the suspension, and the fixed orientation of the agglomerates can further increase the tuning range of the thermal conductivity. In order to prepare high-performance nanoparticle suspensions, high thermal conductivity nanoparticles with large aspect ratio are preferred. The new model preliminarily predicts that the thermal conductivity of the highly thermally conductive graphite flake suspension can vary 10~40 times.A polarization model of rod-like particles was established, and the Brownian dynamics simulation was used to study the 2D motion and micro-aggregation structure of the rod-like nanoparticles. The results show that the time required for a single rod-shaped nanoparticle to rotate to the direction of the electric field is on the order of milliseconds, and the longer the initial angle between the nanoparticle and the electric field, the longer time it takes; the two-particle system eventually forms two types of structures, i.e. end-to-end and overlapping. The walls attract the particles, and the axial direction of the particles will eventually be perpendicular to the walls. Under the electric field, the rod-like particles form a chain structure in the suspension, and as the particle volume fraction increases, the chains becomes longer. When the nanoparticle volume fraction increases to 6%, the long chains in the micro-aggregation structure influence each other to form a more complex dendritic structure.Two kinds of thermal smart materials, GNS / LDH- silicone oil suspension and C / GNS- silicon oil suspension, were prepared by a three-step method. By using a high-speed camera to record the formation of the microstructure of the material, it is observed that the greater the electric field strength, the thicker the chain structure of the thermal smart material. The thermal conductivity of the materials were measured by a laser flash method. The experimental results show that with the increase of electric field strength, the chain structure of thermal smart materials is thicker. For GNS / LDH thermal smart materials, the thermal conductivity increases when the electric field strength increases, and the maximum increase rate relative to the thermal conductivity of the base fluid is 50%. The tuning of the thermal conductivity of the material is reversible, and by opening and closing the electric field the tuning range can be 100%~128%. For C/GNS thermal smart materials, when the electric field strength is less than 400V/mm, the regulation rate of the thermal conductivity of the suspension increases with the increasing electric field strength, and the maximum increase rate is 11.6%.