【作者】 张海涛；

【导师】 叶宏；

【作者基本信息】 中国科学技术大学 ， 动力工程及工程热物理， 2015， 硕士

【摘要】 采用合肥、南京、新疆若羌和黑龙江漠河地区典型气象日及典型气象年数据,探讨周期性环境条件下围护结构热物性对主动通风式热控系统的能耗和目标表面温度时间稳定性及空间均匀性等热控效果的影响。为分析围护结构热物性的作用,采用I-DEAS软件构建实体模型,使用软件中热分析模块(TMG)和电子冷却模块(ESC)分析系统的温度场。选择几种特定的材料,针对不同地区不同典型气候条件,研究围护结构导热系数和体积比热容对系统能耗及热控效果的影响规律,发现降低围护结构导热系数和增大体积比热容有助于降低系统能耗和提高目标表面温度的时间稳定性及空间均匀性。为深入理解围护结构热物性对系统能耗和热控效果影响的一般性影响规律,将实体模型简化为平板模型,基于简化模型遍历分析了典型气象日和典型气象年环境条件下,围护结构的导热系数和体积比热容这两个关键参数对目标热控效果及系统能耗的影响,发现体积比热容的作用规律对导热系数的取值以及进风温度与环境日平均温度的相对高低有很强的依赖。环境日平均温度高于或远低于进风温度时,围护结构热控效果及系统能耗的主要决定因素为导热系数。环境日平均温度与进风温度接近时,在导热系数小于0.1W/(mK)的情况下,体积比热容对热控效果及系统能耗影响较小；但导热系数高于0.1W/(mK)时,增大体积比热容可降低系统平均功耗并提高目标表面温度的时间稳定性及空间均匀性。对比相变材料和隔热材料分别作为高体积比热容和低导热系数围护结构的典型算例,发现使用具有低导热系数和高体积比热容的围护结构材料可降低系统平均功耗、提高目标表面温度的时间稳定性及空间均匀性。更多还原

【Abstract】 A thermal control system with active ventilation was studied, using the environmental data of typical meteorological days and years in Hefei, Nanjing, Ruoqiang and Mohe. Under periodic environmental conditions, the influences of the thermophysical properties of the enclosure on the power consumption and the thermal control effects including the temporal stability and spatial uniformity of the object surface temperature were investigated.In order to analysis the roles of the thermophysical properties of the enclosure, an entity model was built with the software I-DEAS, and the temperature field of the system was calculated through the Thermal Analysis (TMG) and Electronic System Cooling (ESC) modules. Several special materials were chosen to explore the roles of the enclosure’s thermal conductivity and volumetric heat capacity on the power consumption and the thermal control effects with various meteorological data in different areas. It was found that decreasing the thermal conductivity or increasing the volumetric heat capacity of the enclosure can both decrease the power consumption and improve the temporal stability and spatial uniformity of the surface temperature of the object.For further understanding the general roles of the thermophysical properties of the enclosure on the energy consumption and the thermal control effects, the entity model was simplified as a plate model. Under the environmental conditions of typical meteorological days and years, a traversal study was performed on the power consumption of the system and the thermal control effects of the object with enclosures of different thermal conductivity and volumetric heat capacity. It was discovered that the influence of the volumetric heat capacity depends on the value of the thermal conductivity and the difference between the inlet air temperature and the average temperature of the ambient air. When the average ambient air temperature is higher or much lower than the inlet air temperature, the thermal conductivity becomes the dominant factor in average power consumption. And the thermal control effects are both impacted by thermal conductivity and volumetric heat capacity. However, when the average ambient air temperature is close to that of the inlet air, then if the thermal conductivity is less than0.1W/(mK), the volumetric heat capacity has little effect on the average power consumption and the thermal control effects. If the thermal conductivity is higher than0.1W/(mK), a higher volumetric heat capacity could not only reduce the average power consumption but also enhance the temporal stability and spatial uniformity of the object surface temperature. Application performances of phase change materials and thermal insulation materials were discussed as two typical materials that have either a high volumetric heat capacity or a low thermal conductivity. The results shows that the enclosure material with both a low thermal conductivity and a high volumetric heat capacity has the best performance in the average power consumption, the temporal stability and spatial uniformity of the object surface temperature.更多还原