The flow rate of a Fixed-Displacement Pump is 10x what I desired based on the provided displacement.

I am attempting to insert a fixed-displacement pump block into a simscape fluids model such that it reflects a pump that is rate for a 10 gal/min flow rate at an operating speed of 1500 rpm.

The specs of the pump do not give displacement, only the flow rating at each speed. All I want to do is calculate the displacement per revolution that will give me that flow rate. I started by taking 10 gal/min / 1500 rpm to find 0.0068 gal/rev which I insert as the block's parameter.

Working with an isolated pump which is feeding from one atmospheric reservoir to another, using hydraulic fluid with a density of 845 kg/m^3, I see a flow almost 10x what I expected, ~95 gal/min.

I though this may have been an issue with units but even after converting the displacement parameter to m^3/rev, the result is the same. I am unsure if I am overlooking something small that is leading to this issue... any help is appreciated.

This is the parameter set I am using,

%% Pump parameters
pump.disp_gal = 10 / 1500;         % 10 gal/min @ 1500 rpm = 0.00667 gal/rev
pump.nom_ang_vel = 100;   % rpm
pump.nom_p_gain = 1;      % bar
pump.vol_eff = 0.98;
pump.mech_eff = 0.95;

Here is an image of the isolated pump model in Simulink.

Answer 1

[Noah]

The issue was twofold.

1. I did not select units for the constant speed input to the pump, leading it to be interpret 1500 rad/s instead of rpm
2. The second sensor port was placed on top of the first leading me to mix up the mass and volumetric flow, confusing me further

Addressing those two issues resolve everything, allowing me to see the expected 10 gal/min of flow.