Dynamic simulation of innovative aircraft air conditioning

Abstract

The development of innovative air conditioning systems for passenger aircrafts requires the application of dynamic simulation. FLECS, the "Functional Model Library of the Environmental Control System", was programmed to support such development processes of environmental control systems (ECS). FLECS offers a library with generic models from small ECS components up to the whole aircraft cabin. Fundamental to FLECS is the functional simulation in a MATLAB/Simulink environment based on a generalized volume and generalized resistances – mass flow resistances as well as heat flow resistances. Based on these generalized elements, specialised components like isobaric volumes and fan components were derived. Using measured datasets recorded during a test flight of an Airbus A340-600, a set of duct components as well as a cabin model was validated. The measured data was matched in both cases by the simulated response of the system. The validated duct components and the cabin model were used to simulate the control behaviour of an ECS. The cabin model of this simulation consisted of 2 zones of a single aisle aircraft. A highly dynamic test case was defined. The simulated behaviour of the system was plausible and could be well interpreted.