Nozzle extension


Nozzle extension
Artist rendition of liquid rocket engine J-2X with expanded nozzle extension.
The mockup of NK-33-1 with a nozzle extension.

Nozzle extensionnozzle expander of reaction/rocket engine. The application of nozzle extensions improves efficiency of rocket engines in vacuum by increasing nozzle ratio. As a rule, their modern design assumes use of carbon-carbon materials without regenerative cooling. Along with sliding expanders, stationary nozzle extensions have some applications too.

Contents

Description

At present 2009 year, the search for various schemes to achieve higher area ratios for rocket nozzles stays an active field of research and patenting.[1][2] Generally, modern application of these designs can be divided on use for engines, which start their work at sea level and finish it at vacuum conditions, and on use for engines, which perform all their operations in vacuum.

"Air-to-vacuum" engines

For first stage rocket engines, the engine works with nozzle extension in disposed position during the first minutes of flight and expands it at some predefined level of air pressure. This scheme assumes the outer skirt of the bell is extended while the engine is functioning and its installation to working position happens in the upper layers of the atmosphere. It excludes problems with flow separation at sea level and increases efficiency of the engine in vacuum.[3] For example, application of nozzle extension for liquid rocket engine NK-33 improves the value of specific impulse up to 15-20 sec for near-space conditions. Therefore, this scheme adjusts the system to ambient conditions along the trajectory or, in other words, allows altitude compensation.

"Vacuum" engines

Rocket engines of upper stages perform all their operations in space and therefore in a vacuum. In order to achieve maximum efficiency for this class of engines they need high area ratios. This makes the nozzles a very sizable part of engine, which must be completely enclosed below the nose cone of rocket. The payload fairing and supporting constructions must endure all stresses and loads during launch and flight. Consequently, the use of outer expandable skirt in this case allows the size of upper stage and payload fairing to be minimized, which in turn decreases the total mass of the nose cone.[4] For these reasons, nozzle extensions are used for rocket engines RL-10 and RD-58.[4][5]

See also

References

  1. ^ (Russian) Extractable nozzle for rocket engine - Russian Patent 2180405, Russian patents
  2. ^ (Russian) Extractable nozzle for rocket engine - Russian Patent 2190111, Russian patents
  3. ^ (Russian) Work on modifying NK-33, News of cosmonautics, November 2002
  4. ^ a b RL10B-2 - NOZZLE EXTENSION ASSEMBLY IMPROVEMENTS FOR DELTA IV
  5. ^ (Russian) Expandable and fixed nozzle extensions without regenerative cooling, Discussion thread at "News of cosmonautics" forum

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • NE — Nozzle Extension Contributor: MSFC …   NASA Acronyms

  • LE-7 — The LE 7 and it’s succeeding upgrade model the LE 7A are staged combustion cycle LH2/LOX liquid rocket engines produced in Japan for the H II series of launch vehicles. Design and production work was all done domestically in Japan, the first… …   Wikipedia

  • Space Shuttle Solid Rocket Booster — The Space Shuttle Solid Rocket Boosters (SRBs) are the pair of large solid rockets used by the Space Shuttle during the first two minutes of powered flight. They are located on either side of the orange external propellant tank. Each SRB produces …   Wikipedia

  • F-1 (rocket engine) — The F 1 is a rocket engine developed by Rocketdyne and used in the Saturn V. Five F 1 engines were used in the S IC first stage of each Saturn V, which served as the main launch vehicle in the Apollo program. History The F 1 was originally… …   Wikipedia

  • Vinci (rocket engine) — Vinci is a European Space Agency cryogenic rocket engine currently under development. It is designed to power the new upper stage of Ariane 5, ESC B, and will be the first European re ignitable cryogenic upper stage engine, raising the launcher s …   Wikipedia

  • Сопловой насадок — Иллюстрация ЖРД J 2X с выдвинутым сопловым насадком …   Википедия

  • NK-33 — Role: 1st stage multi engine Propellants: RP 1/LOX Development year: 1970 s Overall dimensions Height 3.7 m (12 ft) Diameter …   Wikipedia

  • Vulcain (ракетный двигатель) — Vulcain (Вулкан) Двигатель «Vulcain» в музее. Тип: ЖРД Топливо: жидкий водород …   Википедия

  • TCANE — Thrust Chamber Assembly Nozzle Extension Contributor: MSFC …   NASA Acronyms

  • Glossary of firefighting equipment — Note: This list is incomplete. You can help Wikipedia by [http://en.wikipedia.org/w/index.php?title=Glossary of firefighting equipment action=edit adding to it] . 0 9 * 1 3/4 inch hose: see attack hose * 2 1/2 inch hose: see attack hose , supply… …   Wikipedia