Where is the combustion chamber in a nozzle?
In the context of this exercise I will define the combustion chamber as the section from the injector face not including the injector itself, to the throat of the nozzle. It is seemingly a simple component, at least from a sizing perspective but there are are a few things that must be carefully examined.
How are propellants injected into the combustion chamber?
Injection and atomization zone: The propellants are injected and atomized into tiny droplets either by fluid shear or by impingement. Pre-burning reactions occur here with some level of heat release, but the reactant temperatures and contact areas are not big enough for large scale heat release.
Where does the heat release from the nozzle take place?
The combustion chamber is the chamber upstream of the nozzle where the majority of the heat release from the propellants take place. In the context of this exercise I will define the combustion chamber as the section from the injector face not including the injector itself, to the throat of the nozzle.
What are the requirements for a combustion chamber?
Minimum chamber pressure drop tends to shy us away from long narrow combustion chambers, as does the minimum dimensions and minimum heat rejection requirements. Maximum combustion stability is an interesting one.
How big should the nozzle be for a combustion chamber?
We’re going to go with the usual cylindrical chamber design, and choose a chamber to throat diameter ratio of 4. This means we will use a chamber diameter of about 97.64 mm. Accounting for the cylinder volume, plus the conical convergent section of the nozzle, we can calculate the length of the cylinder part of the chamber to be 77.73 mm.
How is the throat of a combustion chamber calculated?
From these values we can calculate the throat cross-section area to be 4.68 cm2 (using the universal gas constant and molecular weight of 24 g/mol) which corresponds to a throat diameter of 24.4 mm. Using the throat diameter, we can calculate the nozzle exit diameter using some fancy math and the nozzle exit velocity.
How is gas injection used in rocket combustion?
combusting gas-gas injection in a rocket combustion chamber. This facility, capable of chamber pressures of 10 atmospheres, is used to obtain a better understanding of the complex fluid dynamics and combustion processes found in rocket combustion chambers and to provide data to assess NASA’s computational fluid dynamics codes. Visual flame
What kind of nozzle does a rocket engine use?
Most large rocket engines use bell-shaped nozzles, which start with a large divergent angle right after the throat, and gradually decrease the angle, ending in a shallow divergent angle at the nozzle exit.
