Advanced Technology in the Design of Environmental Control System for Avionics Pods

To ensure the reliability of equiments mounted in the avionics pods, an environmental control system (ECS) should be equipped in the pod independently. There are two difficulties in designing pod ECS: one is that the aircraft has no enough electrical power to drive the pod ECS; another is that some elements and devices can't suffer higher temperature, which requires a good environmental condition. This paper introduces a new ram air driven ECS for the avionics pods, which adopts the design concept of cool thermal storage for saving energy. The system operates on a reverse bootstrap air cycle and with a regenerative heat exchanger as well as an intelligent control subsystem. To overcome the difficulty of low ram air pressure head, by use of aerodynamic theory, the total pressure recovery σ of the ram air inlet is raised and the differential pressure between the inlet and outlet air of the ECS is increased, therefore, the greater expansion ratio ε of the cooling turbine is acquired. Test results demonstrate that the designed system has good performance.