An Available-to-Implement Thermal Facility for Dynamic Bleed Air Test of Aircraft Environmental Control System

As a critical system of onboard aircraft equipment, the environmental control system (ECS) has an essential impact on flight safety. The performance of the ECS is usually tested using the thermal test facility. The facility comprises temperature and pressure simulation units to simulate the engine bleed air. Currently, the ECS often fails due to the dynamic and rapid changes in the temperature and pressure of bleed air. To achieve the dynamic bleed air simulation, the most critical problem is to simulate the bleed air's rapid heating and boost process during the actual engine working process. However, the temperature simulation unit has the characteristics of nonlinear and large inertia. Moreover, temperature and pressure control are strongly coupled. These characteristics usually lead to temperature and pressure dynamic control failure. This paper introduces a novel facility that adopted the hot and cold blending method to realize the rapid response of the temperature. Furthermore, it used a particular system structure to reduce pressure and temperature control coupling. In addition, it adopted the lookup-table-based PID (LPID) controller to acquire the rapid response and good steady-state performance of temperature and pressure control. Experimental control results are presented and discussed. The results showed that the facility could meet ECS's dynamic and steady-state test requirements. The novel facility makes up for the insufficient dynamic test capacity of the previously developed ECS test facilities.