Moisture prediction for civil aircraft cabin

Relative humidity level affects cabin comfort of civil aircraft. In this paper, a prediction method of relative humidity was developed based on a well-mixed zonal model. To improve the prediction accuracy, a Lumped Virtual Moisture Source (LVMS) and its two-node moisture transfer model were established to describe a moisture desorption-absorption process of the total of interiors materials in a simple way. The conception of lumped moisture capacity and lumped moisture resistance was firstly introduced to represent moisture storage capability and moisture transfer resistance for the total interior materials. A parameter identification procedure was further presented to obtain these two model parameters of LVMS for different types of civil aircrafts using measured data onboard. Cabin environmental measurements were carried out in five types of civil aircrafts. Compared with continuously measured data during flight, the method to predict the cabin relative humidity can adapt to different types of aircrafts and agree with measured data well. This study may provide some help to develop a reasonable humidity control strategy and suggest proper water storage of humidifier.