环境友好型聚氨酯泡沫低温热物性测试装备的开发

Experimental equipments development for thermal properties of environmental friendly polyurethane foams at low temperatures

为了保护臭氧层,用于生产聚氨酯泡沫的CFC-11发泡剂已经被淘汰,新开发的环境友好型聚氨酯泡沫用于低温设计时缺乏热物理性质数据的支持。文中介绍了开发的三套实验测试系统,以对热导率、线性膨胀系数和比热容这三大热物性在从室温到低温一个宽广的制冷及低温温度区间内进行测试。测试系统采用多项措施保证低温测试所需要的真空环境及漏热问题,保证了测试的顺利进行,以期提供制冷工程设计急需的低温热物性数据,并对泡沫的生产工艺进行优化。

Polyurethane foams manufactured with blowing agent of CFC - 11 were already forbidden all over the world in order to protect the ozone layer. The absence of important thermophysical properties for newly developed environmental friendly PU foams with new blowing agents, like HFC series, water and cyclopentane, is a main obstacle for designers when using the new foams as heat insulation layer at low temperatures. To solve such problems, in this paper, three experimental setups were devel- oped in order to investigate the three important thermal properties including the mean apparent thermal conductivity, thermal expansion coefficient and specific heat. Many effective measures were taken to insure the vacuum condition and no heat leaking for the testing systems at low temperatures. Through the three experimental setups, not only the three important thermal properties at low temperatures for the environmental friendly PU foams will be obtained smoothly but also the heat insulation performance of the PU foams will be improved in the presence of detailed thermal property data.