Difference between revisions of "Propulsion"
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This is the equation that links the electrical power, the propulsive force and the ISP. | This is the equation that links the electrical power, the propulsive force and the ISP. | ||
| − | + | P = F x ISP *9,81 / 2n or P= F x Ev /2n | |
| − | + | where: | |
| + | |||
| + | P = power (Watts) | ||
F = Engine force (Newtons) | F = Engine force (Newtons) | ||
| Line 15: | Line 17: | ||
ISP = Specific impulse (Seconds) | ISP = Specific impulse (Seconds) | ||
| − | n = efficiency of | + | n = efficiency of engine |
9,81 conversion factor | 9,81 conversion factor | ||
| Line 38: | Line 40: | ||
===Velocity=== | ===Velocity=== | ||
| − | V = Ev x ln( | + | V = Ev x ln(M<sub>o</sub>/M<sub>f</sub>) |
Ev = Exhaust velocity (m/s) | Ev = Exhaust velocity (m/s) | ||
| Line 46: | Line 48: | ||
ln = natural logarithm | ln = natural logarithm | ||
| − | + | M<sub>o</sub> = Initial mass of the ship (kg) | |
| − | + | M<sub>f</sub> = Final mass of the ship (kg) | |
The propulsive force is the force the engines produce to push the ship. This is factor of the available electrical energy, the engine efficiency and the propulsive system ISP and ejection velocity. | The propulsive force is the force the engines produce to push the ship. This is factor of the available electrical energy, the engine efficiency and the propulsive system ISP and ejection velocity. | ||
Revision as of 12:01, 5 August 2019
Theory
Propulsion equation
This is the equation that links the electrical power, the propulsive force and the ISP.
P = F x ISP *9,81 / 2n or P= F x Ev /2n
where:
P = power (Watts)
F = Engine force (Newtons)
ISP = Specific impulse (Seconds)
n = efficiency of engine
9,81 conversion factor
Ev = Exhaust velocity (m/s)
Specific impulse
ISP = Ev / 9,81
ISP = Specific impulse (Seconds)
Ev = Exhaust velocity (m/s)
Fuel consumption
m = F/Ev
m = Fuel consumption (kg/s)
F = Force (Newtons)
Ev = Exhaust velocity (m/s)
Velocity
V = Ev x ln(Mo/Mf)
Ev = Exhaust velocity (m/s)
V = ship final velocity (m/s)
ln = natural logarithm
Mo = Initial mass of the ship (kg)
Mf = Final mass of the ship (kg)
The propulsive force is the force the engines produce to push the ship. This is factor of the available electrical energy, the engine efficiency and the propulsive system ISP and ejection velocity.
