In a Cold Gas Propulsion Rocket Engine, the term “cold gas” refers to a propulsion system that uses compressed gas, typically stored at ambient or low temperatures, as a propellant. The combustion process in this type of rocket engine is characterized by the rapid expansion of the compressed gas through a nozzle to generate thrust. Since the gas is not combusted with an oxidizer, the term “cold gas” is used to emphasize that the combustion process does not involve high-temperature combustion like in traditional rocket engines.
In a Cold Gas Propulsion system, the adiabatic expansion temperature (Texpansion) can be used to estimate the temperature drop that occurs as the compressed gas expands through the nozzle. The formula for adiabatic expansion temperature is:
Where:
- : Adiabatic expansion temperature (in Kelvin).
- : Initial temperature of the compressed gas (in Kelvin).
- : Final pressure of the expanded gas (in Pascals).
- : Initial pressure of the compressed gas (in Pascals).
- : Ratio of specific heats ().