Simulation analysis of key dynamic performance of aircraft air flow control system

The bleed air of the wing anti-icing system accounts for a large proportion of the total bleed air, and the opening and closing of the anti-icing valve will cause large fluctuations in the outlet temperature and pressure of the pre-cooler (PCE). In this paper, a system-level dynamic model was established to simulate the response of each component in the aircraft air flow control system including the bleed air system, the air conditioning system and the anti-icing system to the flow step change, and the coupling effect of wing anti-icing on the air conditioning system and other subsystems was analyzed. The study found that within 30 seconds after the wing anti-icing flap was opened, the air temperature at the PCE outlet increased by 100°C, deviating from the set point, and the pressure at the inlet of the air conditioning system decreased by nearly 3.5 psi within 15 seconds, with a risk of cutting off the bleed air, indicating that the system has poor ability to adjust the fluctuation of the bleed air parameters. In the frequency domain analysis of the control system, the PCE time constant increases with the increase of flight altitude, the system stability decreases, the overshoot increases, but the system accuracy increases, and at the same time, over-adjustment and oscillation phenomena will also occur.