Study on construction and identification of dynamic model of precooler in aviation bleed air system

The bleed air from the aircraft engine, serving as the hot-end gas, is pre-cooled through the bleed air system, and subsequently used for cabin temperature regulation and wing anti-freezing. To implement digital intelligent control and enhance the aircraft bleed air system's performance, the identification of dynamic parameters in the system's precooler model is studied. The finite element method was used to establish the partial differential equation of the heat exchange mechanism, and the heat exchange mechanism of the precooler was analyzed. By establishing the partial differential equations of the heat side, cold side, and partition of the precooler, the influencing factors of the heat exchange performance were analyzed. Finally, by identifying the time constants of the precooler under 36 working conditions, a 36-point orthogonal experiment was constructed to fit the time constant of the precooler, which was then compared with the actual measured results. This verified the fitting accuracy and realism of the dynamic model, which can be used for simulation experiments and controller design.