For a cold gas propulsion rocket engine, the term “cold gas” indicates that there is no combustion occurring, and the propulsion is achieved by expelling pressurized gas. The total energy at the nozzle inlet for a cold gas propulsion system can be described as the sum of the enthalpy and the kinetic energy of the gas.
In cold gas propulsion systems, the gas is typically stored at high pressure and is then released through a nozzle to generate thrust. There is no combustion involved, so the gas exits the nozzle with a certain velocity, contributing to the kinetic energy.
The total energy () at the nozzle Inlet can be expressed as:
where,
- E is the Total Energy, i.e sum of kinetic and potential energy
- is the specific enthalpy of the gas at the nozzle inlet (J/kg),
- is the velocity of the Gas at Nozzle.