基于稳态热流计法的低导热材料检测装备的研发、技术优化与稳定性验证

R&D, Technical Optimization and Stability Verification of Testing Equipment for Low Thermal Conductivity Materials Based on Steady-State Heat Flow Meter Method

摘要: 针对真空绝热板(VIP)等低导热材料(1~50 mW/(m·K))检测中测厚误差大、材料特性干扰显著及进口设备成本高的问题，本文研发了ST-500型稳态热流计法检测装备。通过优化测厚系统(解决上下板水平偏差、升降机冲击等4项关键问题)，测厚标准差降至≤0.017 mm；结合高灵敏度热流计(EKOHF-30S)与Pt100热电阻，实现控温精度±0.05℃、检测准确度±2%。通过3种规格VIP板(硬质349 × 504 × 13.80 mm、中软质300 × 300 × 12.25 mm、软质290 × 400 × 7.25 mm)进行验证：硬质板两种装载方式导热系数误差 ≤ 0.1 mW/(m·K)，软质板“不取出”时厚度衰减0.13 mm (需优先“取出”装载)。与进口耐驰HFM446对比，ST-500重复性更优(测厚标准差0.01 mm vs 0.013 mm)，成本仅为进口设备的1/2，满足GB/T 10295-2008标准，推动了低导热材料检测设备的国产化替代。

Abstract: Aiming at the problems of large thickness measurement error, significant interference from material properties, and high cost of imported equipment in the testing of low thermal conductivity materials (1~50 mW/(m·K)) such as vacuum insulation panels (VIPs), the ST-500 testing equipment based on the steady-state heat flow meter method was developed in this paper. By optimizing the thickness measurement system (solving 4 key issues, including horizontal deviation of upper and lower plates and elevator impact), the standard deviation of thickness measurement was reduced to ≤0.017 mm. Combined with a high-sensitivity heat flux meter (EKOHF-30S) and a Pt100 thermistor, the equipment achieved a temperature control accuracy of ±0.05˚C and a detection accuracy of ±2%. Verification was conducted with 3 types of VIP panels (hard: 349 × 504 × 13.80 mm, medium-soft: 300 × 300 × 12.25 mm, soft: 290 × 400 × 7.25 mm). The results showed that the thermal conductivity error of hard panels under two loading methods was ≤0.1 mW/(m·K), while the thickness of soft panels attenuated by 0.13 mm when using the “non-removal” loading method (the “removal” loading method should be prioritized). Compared with the imported Netzsch HFM446, the ST-500 had better repeatability (thickness measurement standard deviation: 0.01 mm vs 0.013 mm) and its cost was only 1/2 of that of imported equipment. It meets the GB/T 10295-2008 standard and can promote the localization replacement of testing equipment for low thermal conductivity materials.