Spray Nozzles used in the mining processes industry

[Michael V]

I'm testing various nozzles with orifice sizes from 5mm to 40mm. The feed water comes from a hopper that is open to atmosphere into a pump. The pump has a flowmeter at the outlet. Then a pipe feeds the pumped water to the nozzle rig. The nozzle is spraying down onto screen filters. In terms of Bernoulli's theorem,

$\frac{P_{1}}{ρg}$+$\frac{V_{1}^{2}}{2g}$+Z₁ = $\frac{P_{2}}{ρg}$+$\frac{V_{2}^{2}}{2g}$+Z₂

is P₂ atmospheric pressure or how would I measure this?

 

[SteamKing]

It would help if you could post a simple diagram of your test setup showing what you are trying to measure.

 

[Michael V]

Here is the simple diagram. So we have a pressure reading at the gauge, which is the reading for the larger pipe in which the nozzle screws into. I'm trying to calculate a coefficient of discharge, so can it be said that our pressure at the nozzle will be atmospheric pressure as it is discharging onto a open screen? I do not agree that it is but another engineer thinks this is correct.