Table of Contents
How do you calculate nozzle expansion ratio?
We must find that area of the nozzle where the gas pressure is equal to the outside atmospheric pressure. This area will then be the nozzle exit area. where Pa is the pressure of the ambient atmosphere. The section ratio, or expansion ratio, is defined as the area of the exit Ae divided by the area of the throat At.
How are rocket nozzles designed?
Rockets typically use a fixed convergent section followed by a fixed divergent section for the design of the nozzle. This nozzle configuration is called a convergent-divergent, or CD, nozzle. The exit velocity, pressure, and mass flow through the nozzle determines the amount of thrust produced by the nozzle.
What is the formula for expansion ratio?
Linear thermal expansion is ΔL = αLΔT, where ΔL is the change in length L, ΔT is the change in temperature, and α is the coefficient of linear expansion, which varies slightly with temperature.
What is the combustion chamber pressure?
Rocket combustion chambers are normally operated at fairly high pressure, typically 10–200 bar (1–20 MPa, 150–3,000 psi).
What is combustion chamber in rocket?
The combustion chamber was the engine’s heart, as it was here that the propellants-liquid oxygen and water alcohol-came together and burned at a temperature of about 2700 C (4900 F). Eighteen injectors on top sprayed the propellants into the chamber.
What does a combustion chamber look like?
Spark-ignition engines In spark ignition engines, such as petrol (gasoline) engines, the combustion chamber is usually located in the cylinder head. Common shapes for the combustion chamber are typically similar to one or more half-spheres (such as the hemi, pent-roof, wedge or kidney-shaped chambers).
What is the pressure inside the nozzle of a rocket?
The nozzle is usually made long enough (or the exit area is great enough) such that the pressure in the combustion chamber is reduced at the nozzle exit to the pressure existing outside the nozzle. If the rocket engine is being fired at sea level this pressure is about 14.7 pounds per square inch (psi).
How can I determine the nozzle dimensions and configuration?
The nozzle dimensions and configuration can be determined from the analyses presented in Chapter 3. The converging section of the supersonic nozzle experiences a much higher internal gas pressure than the diverging section and therefore the design of the converging wall is similar to the design of the cylindrical chamber wall.
What is the effect of chamber pressure on nozzle length?
For the same thrust the combustion volume and the nozzle throat area become smaller as the operating chamber pressure is increased. This means that the chamber length and the nozzle length (for the same area ratio) also decrease with increasing chamber pressure. The performance also goes up with chamber pressure.
What is the range of the chamber volume of a rocket?
The chamber includes all the volume up to the throat area. Typical values for L* are between 0.8 and 3.0 meters (2.6 to 10 ft) for several bipropellants and higher for some monopro-pellants.