The thrust coefficient, often denoted as Ct, is a dimensionless parameter used to characterize and compare the thrust performance of a propulsion system, typically a jet engine or rocket engine. It relates the actual thrust produced by the engine to the theoretical thrust that could be generated under certain ideal conditions.
The formula for calculating the thrust coefficient (Ct) is as follows:
Ct = (T / P * A)
Where:
- Ct is the thrust coefficient (dimensionless).
- T is the actual thrust produced by the engine in newtons (N) or pounds-force (lbf).
- P is the dynamic pressure of the incoming air or exhaust gases at the engine inlet or nozzle exit in pascals (Pa) or pounds per square foot (psf).
- A is the throat area of the engine nozzle or inlet area in square meters (m²) or square feet (ft²).
The thrust coefficient is a useful parameter for comparing the actual thrust of different engines while taking into account the dynamic pressure and the size of the engine’s throat or inlet. It allows for a standardized comparison of thrust performance across different engines and operating conditions.
In some cases, the thrust coefficient is used to determine an engine’s efficiency, particularly in the context of jet engines. It is also valuable in aerodynamic and propulsion research for analyzing engine performance.