D. Bizzarri & P. Hendrick
Royal Military Academy of Belgium (RMA)
Department of Mechanics,
30, Renaissance Avenue, B-1000 Brussels, BELGIUM
D.Bizzarri, P.Hendrick,
Study and Development of an Air Distillation Subscale Unit for In-Flight Oxygen Collection,
AIAA 12th intl Space Planes and Hypersonic Systems & Technologies Conference.
15-19 December 2003, Norfolk, AIAA-2003-6930
In-flight Oxygen Collection is a conceptual design approach of orbital launchers that has the potential to improve significantly the payload of space launch vehicles with technologies available in a rather short term. In those vehicles, the cooling capacity of the fuel, liquid hydrogen, is used during a first air breathing phase of the flight to enrich in oxygen and liquefy a fraction of the incoming air. The main advantages of the concept, applied here to TSTO’s, are a much reduced take off mass, a reduced mass for the liquid rocket engines and a much increased operational flexibility in terms of reachable orbit and launch window. Although many system studies have been performed, only few experimental studies were made and the separator often remained a black box in the vehicle flowsheet. Previous studies on a separator based on a vortex tube by Balepin and Ngendakumana [2]-performed in the scope of the ESA FESTIP research frame- have lead to the conclusion that the device was not suitable for the concepts studied at RMA, since it was unable to provide simultaneously both the required purity and separation efficiency.
As a consequence, the present project will concentrate on the study of a centrifugal distillation device. The project is funded by ESA with the support of the Space research department of the Belgian Federal Science Policy Office. From a theoretical viewpoint, the internal arrangement of the separator will be rethought to fit the requirements of the RMA concepts, for instance, two TSTO vehicles with reusable air breathing first stages, staging being respectively supersonic and subsonic. The experimental demonstration is to be performed first in the form of a reduced scale mass exchanger that will allow to measure a partial enrichment and measure the flow limitations at various rotational speeds, results being scalable to a bigger unit. The general problem of transposing the vertical column to a rotating apparatus is discussed and simple preliminary design techniques are used to derive main requirements for the separator internal layout, mainly in terms of so-called transport units or equivalent ideal trays. Manufacturing the separator is a main issue and different options are explored, taking advantage of present technology when possible. Subsequent work to be performed, mainly building of a higher capacity device, and main issues are discussed.