Sensitivity of Pre-cooled Air-breathing Engine Performance to Heat Exchanger Design Parameters
- Paper number
IAC-06-D2.P.2.07
- Author
Ms. Helen Webber, University of Bristol, United Kingdom
- Coauthor
Mr. Alan Bond, United Kingdom
- Coauthor
Mr. Mark Hempsell, University of Bristol, United Kingdom
- Year
2006
- Abstract
Pre-cooled air-breathing liquid hydrogen fuelled engines derived by integration with a closed cycle rocket engine are currently the only credible means of realising a Single Stage To Orbit (SSTO) vehicle. Pre-cooled air-breathing engines alone also hold a unique promise for efficient flight to Mach 5. These powerful engine concepts lead the way for a sustainable future in space and also provide the means for economic non-stop antipodal flight in about 4 – 5 hours.
High effectiveness heat exchangers are a new addition to the cycles of flying propulsion systems and large pre-coolers for air-breathing engines are a great technical challenge. The pre-coolers of the SABRE engines (Synergetic Air-Breathing and Rocket Engine), proposed for the SKYLON SSTO vehicle, must each transfer some 400 MW of heat in a component having a mass of 1250 kg, with an effectiveness of well over 90
Reaction Engines Ltd, in conjunction with industrial partners, has addressed the materials and manufacturing challenges and has successfully produced a prototype pre-cooler module made from small diameter Inconel 718 tubing. Experimental testing of scaled down pre-coolers has already confirmed the ability to deliver the necessary power transfer rates for operation throughout the air-breathing regime. A programme is now underway to demonstrate a full pre-cooler on a modified gas turbine.
It has been found that the heat transfer coefficients attainable within the heat exchanger matrix have a profound effect on the capabilities of pre-cooled engines. A programme of research work is in progress to assess the possibilities and limits for greatly enhancing the performance of the pre-cooler and hence realising the full potential of the engines that employ them.
This paper will discuss the system level impact on pre-cooled engines of the currently achievable heat exchanger heat transfer coefficients, and show that pre-cooled engines are at a performance plateau, limited by the heat transfer coefficient on the airside of the heat exchanger. Consideration is given to new technologies for improving the conductive and convective thermal resistances through the airside boundary layers, and the quantitative effect these would have on furthering the propulsion capability of pre-cooled engines.
- Abstract document
- Manuscript document
IAC-06-D2.P.2.07.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.