空调环境陶瓷电加热适应性失效分析与改进

Failure analysis and improvement of electric heating adaptability in air conditioning environment

空调器电辅热广泛应用陶瓷电加热代替管状电加热器,但售后长期使用后出现个别电气强度不够存在电气击穿隐患。结合失效样件确认了失效机理为空调制冷环境下电加热表面会产生和积累大量腐蚀性凝露水垢、水渍。并在模态仿真计算基础上,对陶瓷PTC表面凝露腐蚀的工作流场、温度场进行计算研究,将陶瓷电加热由处冷热风交汇流场优化至靠近后底板侧空气湿度较小、且温度均匀位置。经实验验证确认,实施优化策略后,可保障陶瓷PTC单体热交换性能及整机电气安全、性能等指标,有效改善了陶瓷电加热恶劣环境适应性与可靠性。

Ceramic PTC electric heaters are widely used in air conditioners instead of tubular electric heaters because of their electrical safety advantages,but after long-term use after sale,individual electrical strength is not enough and there are hidden dangers of electrical breakdown.Combined with the failure samples,it is confirmed that the failure mechanism is that a large number of corrosive condensed scale and water stains will be produced and accumulated on the electric heating surface under air conditioning and refrigeration environment.On the basis of modal simulation calculation,the working flow field and temperature field of condensation corrosion on the surface of ceramic PTC are calculated and studied,and the flow field of hot and cold air intersection of ceramic PTC is optimized to a position near the rear bottom plate with less air humidity and uniform temperature.The experimental results show that the optimization strategy can ensure the heat exchange performance of ceramic PTC monomer,the electrical safety and performance of the whole machine,and effectively improve the adaptability and reliability of ceramic PTC in harsh environment.