Air–Hydrogen Heat Exchangers for Advanced Space Launchers

in Journal of Propulsion and Power (2009), 25(6),

This paper deals with air–hydrogen heat exchangers intended to provide in-flight oxygen collection capability to a reusable or semireusable two-stages-to-orbit launcher with an oxygen collection phase in ... [more ▼]

This paper deals with air–hydrogen heat exchangers intended to provide in-flight oxygen collection capability to a reusable or semireusable two-stages-to-orbit launcher with an oxygen collection phase in supersonic cruise at Mach 2.5. It aims to present a theoretical but mainly technological and experimental feasibility study of heat exchangers sufficiently efficient and reliable to suit the extreme requirements of this application. Two precoolers of two different types (shell and tubes, and plate and fins) have been selected and designed with the objective of fulfilling all constraints of the concept in terms of performance, leak tightness, reliability, compactness, etc. This design process has been validated with four subscaled breadboards (two of each type) tested on two test benches (for performance and leak tightness), developed by Belgium and Spain, in on-design and off-design conditions. All these results highlight the suitability of the new technologies given the extreme requirements of the concept. An optimum design for each technology is recommended considering its proper advantages and disadvantages. An innovative precooler technology is presented and tested. [less ▲]

Experimental study of a heat exchanger for an in-flight oxygen collection launcher

in 14th AIAA/AHI International Space Planes and Hypersonic Systems and Technologies Conference (2006, November)

In the scope of an ESA-funded theoretical and experimental study (in the GSTP3 program) on heat exchangers intended to provide in-flight oxygen collection capability to a reusable or a semi-reusable TSTO ... [more ▼]

In the scope of an ESA-funded theoretical and experimental study (in the GSTP3 program) on heat exchangers intended to provide in-flight oxygen collection capability to a reusable or a semi-reusable TSTO launcher with an oxygen collection phase in supersonic cruise, two subscale models of an air-hydrogen precooler and a test set-up are currently being developed in Belgium and in Spain. The vehicle we foresee for this application is described in previous conference papers as well as the work on our ESA-funded airborne air separator, which is the other critical element of the oxygen collection plant. This current paper is concentrating only on the theoretical but mainly the technological and experimental aspects of such an air precooler. The experimental and technical aspects include choices and main trade-offs that have had to be made during the design process by the different partners (Techspace Aero, von Karman Institute, Iberespacio, University of Liège, Royal Military Academy of Belgium and University of Brussels). After we fixed the requirements at system level and at the precooler level, a simulation work of generic heat exchangers is presented including the problem of frost formation and its influence on the heat exchanger performance. A few advanced heat exchanger designs are analysed resulting in a more detailed parametric and performance analysis of two advanced configurations. A detailed study of the most advantageous heat exchangers materials is shown resulting in the selection of the alloys for the two breadboards. The manufacturing processes for these two breadboards are defined, based on trials on small scale models inspired from the two technology candidates. Perspectives are also given for the mechanical and thermodynamic testing of the two breadboards. [less ▲]