an experimental design verification of the dual-bell nozzles
- Paper number
IAC-08.C4.1.6
- Author
Dr. yibai wang, Beijing University of Aeronautics and Astronautics, China
- Coauthor
Prof. yu liu, China
- Coauthor
Mr. yunfei liao, China
- Coauthor
Dr. mengwei zheng, China
- Year
2008
- Abstract
The dual-bell concept is one of the most potential altitude compensating nozzle, and has been received more attention recently. It is expected to provide a significant overall engine performance gain over the conventional bell nozzle due to its capability to adapt the nozzle exhaust gas flow to ambient pressure at both low and high altitude. The dual-bell nozzle is most similar to the conventional bell nozzle and has no any moving parts for improving launch vehicle performance. The dual-bell nozzle has been investigated by means of analytical and experimental work in this paper. First, the principle flow feature of the dual-bell nozzle was discussed. Design parameters for the contour of the base nozzle and the extension were analyzed. The key point is how to assure that the mode transition from sea level to high altitude is rapid. Based on the analytical work, a number of subscale dual-bell nozzles with different structure parameters were manufactured and experimentally tested, in order to explore this concept regarding its aerodynamic characteristics. The hot-firing tests were performed by employing the gaseous oxygen as oxidizer and gaseous hydrogen as fuel. The experimental system, the model configuration, design parameters and assembly graphics were described. Made of the ablation-resistant tungsten-copper alloy, the nozzle components have successfully passed several short-period hot-firing tests. The measured parameter curves, test photographs and results were obtained. High nozzle thrust efficiencies were yielded in the tests. The typical efficiencies of the dual-bell models reached from 95%-98% at different altitudes from sea level to near design point. It is shown that the dual-bell concept really had a good altitude compensating ability, and a sudden transition from sea-level to altitude mode can be achieved though analyzing the distribution of nozzle wall pressure. The influences of different design parameters of the extension contour are also experimental validated.
- Abstract document
- Manuscript document
IAC-08.C4.1.6.pdf (🔒 authorized access only).
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