How to loop a model's output back to the input untill they both converge

I am building a model to calculate the pressure and flow rate for a fuel rig. The model takes in a guessed flow, and based on lookup tables, outputs different pressures. These pressures are used to compute the final flow.

My problem is I want to achieve a convergence (the flow in = flow out), and I want to know how I can loop the result at the flow out to the flow in till they both have the same flow.

Answer 1

[J Chen]

Use a Delay block https://www.mathworks.com/help/simulink/slref/delay.html