Numerical Modelling of Moisture Transport between Two Enclosures Connected by a Tube

Electronic devices are typically protected using plastic or metallic enclosures. However, moisture from the surrounding environment can still enter the enclosure via gasket, plastic enclosure walls and cable feedthroughs. Further, the moisture existing inside an enclosure may condense on top of the PCBA or active electronic components, due to the faster temperature changes experienced by these devices as compared to the other regions within the enclosure, which can in turn lead to moisture-related failures. The local temperature inside an enclosure is dependent on the geometrical design of the enclosure as well as the heating behaviour of the electronic components. The paper concerns the complex transient heat and mass transfer processes between two connected enclosures with one enclosure being warm, while another enclosure is cold. The objective of the paper is to develop an in-house code based on the RC approach for predicting and studying the temperature and moisture behaviour inside two connected enclosures. The developed RC model combines one-dimensional finite volume modelling techniques and lumped analysis methods for heat and mass transport. The modelling of temperature and moisture response is carried out under non-isothermal B3 STANAG ambient conditions. The different plastic materials of warm enclosure wall and the heating in the warm enclosure were studied.