Stepped nozzles
Encyclopedia
A stepped nozzle is a de Laval
rocket nozzle which has altitude compensating properties
.
The characteristic of this kind of nozzle is that part of the way along the inside of the nozzle there is a straightening of the curve of the nozzle contour, followed by a sharp step outwards.
At low altitude this causes the jet to separate at the step, and ambient pressure maintains the jet at this place, avoiding jet instabilities and avoiding massive overexpansion.
As the altitude rises the jet becomes progressively under-expanded and grows until it fills the nozzle, at which point the gas provides more pressure against the rest of the nozzle and thrust and specific impulse
increases.
De Laval nozzle
A de Laval nozzle is a tube that is pinched in the middle, making a carefully balanced, asymmetric hourglass-shape...
rocket nozzle which has altitude compensating properties
Altitude compensating nozzle
An altitude compensating nozzle is a class of rocket engine nozzles that are designed to operate efficiently across a wide range of altitudes.- Conventional designs :...
.
The characteristic of this kind of nozzle is that part of the way along the inside of the nozzle there is a straightening of the curve of the nozzle contour, followed by a sharp step outwards.
At low altitude this causes the jet to separate at the step, and ambient pressure maintains the jet at this place, avoiding jet instabilities and avoiding massive overexpansion.
As the altitude rises the jet becomes progressively under-expanded and grows until it fills the nozzle, at which point the gas provides more pressure against the rest of the nozzle and thrust and specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...
increases.
See also
- Nozzle extensionNozzle extensionNozzle extension — nozzle 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...