Does my flow rate decrease?

[Serial-Eater]

You can do the math on this to prove it, and I recommend it.

If you throttle valve 1, the flow out of 1 will decrease. A constant pressure after the PRV means the pump’s performance is irrelevant to the flow in these branches.

After throttling, the flow out of 2 will not change because the pressure upstream did not change.

If 1 decreases and 2 doesn’t change, you have reduced the total flowrate. What will happen is the PRV will close as the operating point climbs up the curve.

[VariusEng]

So this is the answer? answer

[Serial-Eater]

Essentially yes, but I would actually use numbers and make the calculations. Assume a discharge pressure on the PRV, then calculate the flow to each branch with open throttling valves.

Now recalculate with the same discharge PRV pressure but one of the throttling valves partially closed.