Abstract

A low-pressure air cycle cooling device for cooling the air in a space. The invention includes a cooling chamber, generally drum-like in form, whose interior is defined by end caps and the chamber inner wall. A powered rotor assembly is carried in the chamber, with rotor vanes carried in slots formed in the rotor. The vanes move outward as the rotor rotates, extending to the vicinity of the chamber wall. Vane tips interact with the air in the vicinity of the chamber wall, producing an air bearing effect that minimizes friction while substantially sealing the volume between adjacent vanes. The chamber is generally ovoid in shape, with the long axis being pinched to produce a waist, demarked by pinch points. In the vicinity of such pinch points the chamber wall is curved inwardly concave, while the remainder of the chamber is curved outwardly convex. Four ports are formed in the chamber wall, two of which communicate with the cooled space and two connect with a heat exchanger. The chamber inner wall is divided into a number of zones for performing thermodynamic operations on parcels of air carried between adjacent vanes. The device operates as a rotary vane pump according to the reverse Brayton cycle, in which parcels of air are collected as a pair of vanes passes an inlet port, the parcel of air is compressed, heat is rejected by the heat exchanger, and the parcel is expanded. Cooled air is then exhausted to the space.