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首页> 外文期刊>Energy Conversion & Management >An adiabatic calorimeter for heat capacity measurements of polyurethane foam with blowing agent of HFC245fa in the temperature range 60-290 K
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An adiabatic calorimeter for heat capacity measurements of polyurethane foam with blowing agent of HFC245fa in the temperature range 60-290 K

机译：绝热热量计，用于在60-290 K的温度范围内用HFC245fa发泡剂测量聚氨酯泡沫

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摘要

In order to meet the urgent need of heat insulating materials used under low temperature in the area of aerospace, a new PU foam with HFC245fa as blowing agent was developed. In this paper, the heat capacity in the temperature range of 60-290 K of the new material was measured through an automated adiabatic calorimeter, which was composed of a heat insulation system, a power measuring system, a vacuum pumping system and a cooling system. The sample cell of the calorimeter was equipped with a miniature platinum thermometer surrounded by two adiabatic shields and housed in a high vacuum can. The temperature differences among the sample cell and the inner and outer adiabatic shields could be adjusted automatically to less than 0.05 K, all which ensure there was no heat exchange between the sample and surroundings. Under these conditions, the mathematical formulation of the sample with the physical model was given. Through measuring the heat capacity of α-Al_2O_3, which is a standard reference material, a relatively high reliability with a deviation of ±2.5% of this adiabatic calorimeter was shown compared with the standard data. The results indicate that the newly developed PU foam has a higher heat capacity compared with other heat insulating materials, and there is no obvious sign of any phase transition or thermal anomaly in the entire temperature range. That is to say, the material is thermodynamically stable when used in the low temperature range.
机译：为了满足航空航天领域低温用绝热材料的迫切需求，研制了一种以HFC245fa为发泡剂的新型PU泡沫。本文通过自动绝热热量计测量了新材料在60-290 K温度范围内的热容量，该绝热热量表由绝热系统，功率测量系统，真空泵系统和冷却系统组成。量热计的样品池配备了一个微型铂金温度计，该温度计被两个绝热罩包围，并容纳在高真空罐中。样品池与内部和外部绝热罩之间的温差可自动调节至小于0.05 K，所有这些确保了样品与周围环境之间没有热交换。在这些条件下，给出了具有物理模型的样品的数学公式。通过测量作为标准参比材料的α-Al_2O_3的热容，与标准数据相比，该绝热量热仪的偏差为±2.5％，具有相对较高的可靠性。结果表明，与其他绝热材料相比，新开发的聚氨酯泡沫具有更高的热容，并且在整个温度范围内都没有明显的相变或热异常迹象。也就是说，该材料在低温范围内使用时是热力学稳定的。

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