Valve lift & variable air flowrate in compressed air

AI Thread Summary
Incorporating valve lift and variable flow rate in a compressed air engine involves understanding the relationship between mechanical power, torque, and flow rate. The discussion emphasizes that the power produced is linked to the force on the piston and its speed, rather than just the energy from the fluid flow due to losses like turbulence. Calculating mass flow into the cylinder is essential for determining pressure as a function of crank angle, which can then be used to derive torque. The conversation also touches on the need to adapt calculations to account for flow rate instead of pressure, particularly in modified engine designs. Accurate modeling of these parameters is crucial for optimizing engine performance.
Chotai Nikhil
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How we can incorporate valve lift and variable flow rate in compressed air engine

Mechanical power = air power
torque * angular velocity = pressure * flow rate
 
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There's a lot to your question. Are you asking how to calculate the flow into the cylinder as a function of valve lift?
I don't believe your second expression is that useful. The power produced by the motor (it's not an "engine" because it doesn't run on heat) will be equal to the force on the piston times the piston speed (p*A*dx/dt), but not equal to the rate of energy coming in with the fluid. This is because some of the enthalpy of the incoming flow, through turbulence, will be converted to heat.
You'll need to calculate the mass-flow into the cylinder to get pressure as a function of crank angle theta, and calculate torque from T = p*A*dx/dtheta.
 
Thank you sir

1) I used the Word Engine because i modified the 4 stroke petrol engine to 2 stroke engine

2) how does i incorporate flow rate instead of Pressure "P" because i have flow through valve here and i don't have exact value of Pressure of P incise the cylinder which we call as mean pressure in petrol engine.
 
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