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## Main Question or Discussion Point

Hello everybody,

This is my first post. I've been working on a liquid rocket engine for a while, but I have never gotten to work on its feed system (fluid mechanics), until recently. We are using a very simple pressure fed system, and its main goal is to deliver the propellants at a specific flow and pressure to the engine. I know that Q = v*A, but this doesn't help me that much since I can't "set" the velocity of the pressurized propellants. Nevertheless, I do know their pressures and the cross sectional area of the pipes. I tried to derivate that formula to come up with another one that includes pressure, but even though the units are correct, I don't think it is correct. This is the other formula I know: Q = Cd * A * sqrt(2 dP / rho), where Cd is the discharge coefficient, dP the pressure drop, and rho, the fluid density. Sadly, dP is not very useful here neither.

So in summary, my question is: if I have a pipe of x diameter coming out from a tank with a pressure of y (assuming I know the physical properties of this fluid), what would it be its resulting flow, and how can I change it?

Best,

Roy S. Ramirez

This is my first post. I've been working on a liquid rocket engine for a while, but I have never gotten to work on its feed system (fluid mechanics), until recently. We are using a very simple pressure fed system, and its main goal is to deliver the propellants at a specific flow and pressure to the engine. I know that Q = v*A, but this doesn't help me that much since I can't "set" the velocity of the pressurized propellants. Nevertheless, I do know their pressures and the cross sectional area of the pipes. I tried to derivate that formula to come up with another one that includes pressure, but even though the units are correct, I don't think it is correct. This is the other formula I know: Q = Cd * A * sqrt(2 dP / rho), where Cd is the discharge coefficient, dP the pressure drop, and rho, the fluid density. Sadly, dP is not very useful here neither.

So in summary, my question is: if I have a pipe of x diameter coming out from a tank with a pressure of y (assuming I know the physical properties of this fluid), what would it be its resulting flow, and how can I change it?

Best,

Roy S. Ramirez