Propulsion - Revision history

RichardWSmith at 03:58, 29 September 2024

2024-09-29T03:58:35Z

RichardWSmith: Added link.

2024-09-29T03:58:17Z

Added link.

Michel Lamontagne at 13:32, 27 August 2021

2021-08-27T13:32:21Z

Michel Lamontagne at 13:29, 27 August 2021

2021-08-27T13:29:18Z

Michel Lamontagne: /* Propulsion equation */

2021-08-27T13:24:27Z

Propulsion equation

Michel Lamontagne at 17:39, 9 August 2019

2019-08-09T17:39:54Z

Michel Lamontagne at 01:08, 6 August 2019

2019-08-06T01:08:20Z

Michel Lamontagne at 01:07, 6 August 2019

2019-08-06T01:07:38Z

Michel Lamontagne at 19:01, 5 August 2019

2019-08-05T19:01:15Z

Michel Lamontagne at 21:12, 12 May 2019

2019-05-12T21:12:40Z

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 For a rocket, the first body is the exhaust, a "body" of gas,  and the second body is the rocket nozzle and by extension the entire rocket.  Since the force is directly proportional to the energy in the exhaust, then the energy added to the system must be equal to exactly twice the energy in the rocket exhaust, minus the system losses.  Half of the energy added to the engine will go the the exhaust as kinetic energy, and the other half will go to the vehicle as kinetic energy.
-See also [[Fusion propulsion]].
+See also [[Fusion Propulsion]].
 ==Equations==

← Older revision		Revision as of 03:58, 29 September 2024
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	For a rocket, the first body is the exhaust, a "body" of gas, and the second body is the rocket nozzle and by extension the entire rocket. Since the force is directly proportional to the energy in the exhaust, then the energy added to the system must be equal to exactly twice the energy in the rocket exhaust, minus the system losses. Half of the energy added to the engine will go the the exhaust as kinetic energy, and the other half will go to the vehicle as kinetic energy.		For a rocket, the first body is the exhaust, a "body" of gas, and the second body is the rocket nozzle and by extension the entire rocket. Since the force is directly proportional to the energy in the exhaust, then the energy added to the system must be equal to exactly twice the energy in the rocket exhaust, minus the system losses. Half of the energy added to the engine will go the the exhaust as kinetic energy, and the other half will go to the vehicle as kinetic energy.
		+
		+	See also [[Fusion propulsion]].
		+
	==Equations==		==Equations==

@@ Line 1: / Line 1: @@
 [[Category:Propulsion]]
-The propulsive force is the force an engine produces to push the vehicle. This is factor of the available energy, the engine efficiency and the propulsive system ISP and ejection velocity.  The energy may come from a chemical reaction, a nuclear reaction or external sources (solar or kinetic).
+The propulsive force is the force an engine produces to push a vehicle. This is factor of the available energy, the engine efficiency and the propulsive system ISP and ejection velocity.  The energy may come from a chemical reaction, a nuclear reaction or external sources (solar or kinetic).
 From Newton's third law of motion, the force exerted on a body by a second body is equal and inverse to the force exerted by the second body on the first body.  F<sub>1</sub>=-F<sub>2</sub>

@@ Line 1: / Line 1: @@
 [[Category:Propulsion]]
-==Theory==
+From Newton's third law of motion, the force exerted on a body by a second body is equal and inverse to the force exerted by the second body on the first body.  F<sub>1</sub>=-F<sub>2</sub>
 ===Propulsion equation===
@@ Line 53: / Line 57: @@
 M<sub>f</sub> = Final mass of the ship (kg)

@@ Line 5: / Line 5: @@
 ===Propulsion equation===
-This is the equation that links the electrical power, the propulsive force and the ISP.
+This is the equation that links the power, the propulsive force and the ISP.
-P = F x ISP *9,81 / 2n  or P= F x Ev /2n
+P = F x Isp x 9,81 / 2ɳ  or P= F x V<sub>e</sub> /2ɳ
 where:
-P = power (Watts)
+P = Power (Watts)
 F = Engine force (Newtons)
-ISP = Specific impulse (Seconds)
+Isp = Specific impulse (Seconds)
-n = efficiency of engine, for an [[ion thruster]] this is between 0,2 and 0,8, for a [[Propellant|chemical rocket]], or [[Nuclear thermal propulsion|nuclear thermal rocket]], essentially 1.
+ɳ = efficiency of engine, for an [[ion thruster]] this is between 0,2 and 0,8, for a [[Propellant|chemical rocket]], or [[Nuclear thermal propulsion|nuclear thermal rocket]], essentially 1.
-,81 conversion factor
+,81 conversion factor, Earth gravity (m/s<sup>2</sup>)
-Ev = Exhaust velocity (m/s)
+V<sub>e</sub> = Exhaust Velocity (m/s)
 ===Specific impulse===
-ISP = Ev / 9,81
+Isp = V<sub>e</sub> / 9,81
-ISP = Specific impulse (Seconds)
+Isp = Specific impulse (Seconds)
-Ev = Exhaust velocity (m/s)
+V<sub>e</sub> = Exhaust velocity (m/s)
 ===Fuel consumption===
-m = F/Ev
+ṁ = F/V<sub>e</sub>
-m = Fuel consumption (kg/s)
+ṁ = Fuel consumption (kg/s)
 F = Force (Newtons)
-Ev = Exhaust velocity (m/s)
+V<sub>e</sub> = Exhaust velocity (m/s)
 ===Velocity (Rocket equation)===
-V = Ev x ln(M<sub>o</sub>/M<sub>f</sub>)
+V<sub>f</sub> = V<sub>o</sub> + V<sub>e</sub> x ln(M<sub>o</sub>/M<sub>f</sub>)
-Ev = Exhaust velocity (m/s)
+V<sub>e</sub> = Exhaust velocity (m/s)
-V = ship final velocity (m/s)
+V<sub>f</sub> = ship final velocity (m/s)
 ln = natural logarithm
@@ Line 52: / Line 54: @@
 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 energy, the engine efficiency and the propulsive system ISP and ejection velocity.

@@ Line 17: / Line 17: @@
 ISP = Specific impulse (Seconds)
-n = efficiency of engine, for an [[ion thruster]] this is between 0,2 and 0,8, for a chemical rocket, essentially 1.
+n = efficiency of engine, for an [[ion thruster]] this is between 0,2 and 0,8, for a [[Propellant|chemical rocket]], essentially 1.
 ,81 conversion factor

← Older revision		Revision as of 21:12, 12 May 2019
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	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.
−
−	~~For the Enterprise: Available electrical energy = 2,5 GWe~~
−	~~ISP = 5000~~
−	~~Efficiency (n) = 80%~~
−	~~Thrust = 2 500 000 000 W x 2 x 0,8 / (5000*9,81) = 84 000 N = 8 300 kg = 8,3 Tons~~