Overall design method of ground test equipment for engine dynamic air bleed of aircraft environmental control system

It is a major problem for the aircraft environmental control system (ECS) design and improvement when encountering failures during dynamic operation. The traditional ground test equipment for the ECS only can supply gas in a steady state or a small range at a low speed, and it is difficult to reproduce the environment of rapid and violent dynamic air bleed of ECS in the air. To make up for the lack of dynamic test capability of ECS, China has built a new double-engine dynamic simulation test bench for ECS with the largest parameter coverage and the highest dynamic index, which can simulate the dynamic air bleed environments of different engines under different working states for the ECS. The overall design method of the test bench was introduced in this paper. The combined adjustment of temperature and pressure was realized by the method of using the main valve for pressure regulation and mixing the cold and the hot for temperature adjustment, and the resistance relationship of each link was reasonably distributed to weaken the coupling in the pressure regulation and temperature adjustment process. The rapidity of temperature adjustment was ensured by using a bypass heater for heating and a heat exchanger for heat exchange. Double-valve linkage control was used to ensure the large range and high precision of pressure regulation, and dual flowmeters were employed to ensure steady-state measurement accuracy and dynamic measurement speed. Based on the traditional distributed control system, a fast interactive network of reflective memory cards was established to realize the fast response of the control system, and the proportional-integral-derivative (PID) algorithm based on the expert system was adopted to improve the control effect of the controller. The test results show that the test bench can rapidly and dynamically regulate pressure and adjust temperature in a wide range.