How to calculate the flow rate?

[amare]

A valve is installed between the throttle body and intake manifold and decrease its area to restrict the flow. How do I analyze the mass flow rate of air in the decreasing area to know the engine working condition at a minimum valve area?

 

[AZFIREBALL]

Place an anemometer in the air stream to measure its velocity. The flow rate in the restricted area will be proportional to the ratio of the two air stream cross sections.

 

[amare]

Place an anemometer in the air stream to measure its velocity. The flow rate in the restricted area will be proportional to the ratio of the two air stream cross sections.

I need to model the scenario mathematically...do you have the idea how do i model it?

 

[amare]

I need to mathematically model a valve installed between the throttle body and the intake manifold. the valve is an iris type whose area decrease or increase as needed. when the valve is open the air can flow freely from the throttle body to the intake manifold. but when the area get decreasing the flow will be restricted and when the area becomes zero the engine will stop. so how do i mathematically model and drive equation for this type of scenario?

 

[AZFIREBALL]

See:
https://www.tlv.com/global/US/calculator/air-flow-rate-through-valve.html