How do I calculate the movement of air in a valveless pulse jet engine?

[telepresence]

I'm trying to create a piece of software that can approximate the physics of a valveless pulse jet engine. What I need right now is to figure out the math behind the moving air. How would I calculate how the air from the combustion chamber after combustion (assumed for simplicity to be instantaneous) would move down the exhaust and intake pipes relative to the size of the pipes and the pressure of the air in the chamber? (Yes, I realize this needs calculus) As the gas leaves the combustion chamber, It forms a vacuum in its wake that eventually stops the flow of air and starts pulling it back. I need the equations for this. I also could use some explanation of how the size of an opening effects the amount of pressure placed on it when in this type of scenario (how much of the pressure is exerted on the openings to the exhaust and inlet tubes?

 

[RandomGuy88]

Are you just trying to approximate some particular quantity or are you trying to simulate the entire flow? Because simulating the entire flow is an extremely complex problem that will need a lot more than calculus. Ever hear of the Navier Stokes Equations? That is where you need to start if you are going to simulate a fluid.

 

[telepresence]

for right now I was going to be content with just a simple simulation that incorporated the heat cycle only. I was calculating the amount of energy given by combustion of a given amount of propane (based on the amount of fresh air in the chamber, somewhere between 2.15 and 9.6 [the flamability limits of propane] percent of the air) and then calculating how much that would heat the air. From that calculating the increase in pressure (since I'm assuming all of this is instant, I can also assume that the volume is constant. I know that will result in a much more powerful result than is actually possible, but it's a start).

Ever hear of the Navier Stokes Equations? That is where you need to start if you are going to simulate a fluid.

Thanks for the info, I'll look into it.

 

[telepresence]

does anyone know a conversion for pressure difference to acceleration in air?