Calculating Velocity of Exit Stream in Aircraft - George

In summary, to calculate the velocity of the exit stream in an aircraft, you need to consider factors such as thrust, intake velocity, inlet diameter, and air density. However, the specific formula will depend on the propulsion mechanism being used. If it is a jet engine, the temperature difference between the intake and exit streams and the possibility of supersonic flow must also be taken into account.
  • #1
skydvr8029
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I would like to get some help if possible. I am trying to determine the correct formula to calculate the velocity of the exit stream in an aircraft. I know the thrust, the velocity of the intake, inlet diameter, and air density (ρ). Thanks for any help.

George
 
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  • #2
Thrust is momentum per time - with the known mass flow (mass per time: you have density, velocity and area), you can calculate the velocity difference between intake and exit.
 
  • #3
It depends on the propulsion mechanism. Is this a jet engine? Because if you are considering a jet engine I don't think you have enough information. The temperature of the exit stream is significantly higher than the inlet temperature which means the density is different between intake and exit. So you can determine the mass flux but you do not have sufficient information to determine the velocity. In addition, if the exit stream is supersonic and is not perfectly expanded then the pressure difference between intake and exit will also be contributing to the thrust.
 

FAQ: Calculating Velocity of Exit Stream in Aircraft - George

What is the equation for calculating the velocity of an exit stream in an aircraft?

The equation for calculating the velocity of an exit stream in an aircraft is: v = sqrt(2 * k * R * T), where v is the velocity, k is the specific heat ratio, R is the gas constant, and T is the temperature.

How do you determine the specific heat ratio for a particular aircraft?

The specific heat ratio for a particular aircraft can be found in its specifications or by conducting experiments in a controlled environment. It is a constant value that depends on the type of gas used in the aircraft.

Can the temperature affect the velocity of the exit stream in an aircraft?

Yes, the temperature has a direct impact on the velocity of the exit stream in an aircraft. As the temperature increases, the velocity also increases, and vice versa.

How does the gas constant affect the velocity of the exit stream in an aircraft?

The gas constant, R, is directly proportional to the velocity of the exit stream in an aircraft. This means that as the gas constant increases, the velocity also increases, and vice versa.

What factors can affect the accuracy of the calculated velocity of the exit stream in an aircraft?

The accuracy of the calculated velocity of the exit stream in an aircraft can be affected by factors such as air density, temperature variations, and changes in the specific heat ratio. Additionally, any errors in the initial data or measurement techniques can also impact the accuracy of the calculation.

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