.AixLib.Fluid.Movers.BaseClasses.Euler.getPeak

Information

This function finds or estimates the peak point (V̇,Δp,η)|η=η_max from the input power curve P(V̇) and pressure curve Δp(V̇) which may or may not contain non-zero values. The results are output as an instance of AixLib.Fluid.Movers.BaseClasses.Euler.peak. There are the following branches of computation based on information provided to the function:

• If Δp(V̇) is unavailable, the function simply outputs (0,0,0.7).
• If Δp(V̇) is provided but P(V̇) is unavailable, the function provides an estimation of the peak point at half of max flow rate (V̇_max ⁄ 2, Δp(V̇=V̇_max ⁄ 2), 0.7).
• If both Δp(V̇) and P(V̇) are available, the function first computes η(V̇)=V̇ Δp ⁄ P.
  • If η(V̇) has less than four data points or is monotonic, use one of the two which ever produces a higher η:
    • The interpolated point at half of max flow rate (V̇_max ⁄ 2, Δp(V̇=V̇_max ⁄ 2), η(V̇=V̇_max ⁄ 2))
    • The available point with the highest computed efficiency.
  • Otherwise, the function runs a quartic regression on η(V̇) then solves its derivative to find an extremum. It assumes that there is only one extremum on the open interval (0,V̇_max).

Interface

function getPeak
  extends Modelica.Icons.Function;
  input AixLib.Fluid.Movers.BaseClasses.Characteristics.flowParameters pressure "Pressure vs. flow rate";
  input BaseClasses.Characteristics.powerParameters power "Power vs. flow rate";
  output AixLib.Fluid.Movers.BaseClasses.Euler.peak peak "Operation point at maximum efficiency";
end getPeak;

Revisions

• August 18, 2022, by Hongxiang Fu:
  First implementation. This is for #2668.