Pressure difference is calculated with:

$\mathrm{dp}\=\frac{1}{A\cdot \mathrm{\α\_\_linear}}\cdot \mathrm{mflow}$

Mass flow rate is calculated with:

$\mathrm{mflow}\=A\cdot \mathrm{\α\_\_linear}\cdot \mathrm{dp}$

Pressure difference is calculated with:

$\mathrm{dp}\=\frac{1}{{\left(A\cdot \mathrm{\α\_\_sqrt}\right)}^2}\cdot {\mathrm{mflow}}^2\cdot \mathrm{sign}\left(\mathrm{mflow}\right)$

In theory, Mass flow rate is calculated with:

$\mathrm{mflow}\=A\cdot \mathrm{\α\_\_sqrt}\cdot \sqrt{\mathrm{dp}}$

In the Heat Transfer Library, the following equation is used to resolve difficulties of the numerical calculation:

$\mathrm{mflow}\=A\cdot \mathrm{\α\_\_sqrt}\cdot \mathrm{`HeatTransfer.Functions.regRoot`}\left(\mathrm{dp}\,\mathrm{sharpness}\right)$

(*) $\mathrm{`HeatTransfer.Functions.regRoot`}$ is the same function as $\mathrm{`Modelica.Fluid.Utilities.regRoot`}$. To check the details of the package and view the original documentation, which includes author and copyright information, click here.

Pressure difference is calculated with:

$\mathrm{dp}\=\frac{1}{2}\cdot \mathrm{\λ}\cdot \frac{L}{\mathrm{D\_\_h}\cdot A^2\cdot \{\begin{array}{cc}\mathrm{inStream}\left(\mathrm{`port\_a.rho`}\right)& \mathrm{dp}\ge 0\\ \mathrm{inStream}\left(\mathrm{`port\_b.rho`}\right)& \mathrm{others}\end{array}}\cdot {\mathrm{mflow}}^2\cdot \mathrm{sign}\left(\mathrm{mflow}\right)$

In theory, Mass flow rate is calculated with:

$\mathrm{mflow}\=\sqrt{\frac{2\cdot \mathrm{D\_\_h}\cdot A^2}{\mathrm{\λ}\cdot L}}\cdot \sqrt{\{\begin{array}{cc}\mathrm{inStream}\left(\mathrm{`port\_a.rho`}\right)& \mathrm{dp}\ge 0\\ \mathrm{inStream}\left(\mathrm{`port\_b.rho`}\right)& \mathrm{others}\end{array}\cdot \mathrm{dp}}$

In the Heat Transfer Library, the following equation is used to resolve difficulties of the numerical calculation:

$\mathrm{mflow}\=\sqrt{\frac{2\cdot \mathrm{D\_\_h}\cdot A^2}{\mathrm{\lambda }\cdot L}}\cdot \mathrm{`HeatTransfer.Functions.regRoot2`}\left(\mathrm{dp}\,\mathrm{dp\_small}\,\mathrm{inStream}\left(\mathrm{`port\_a.rho`}\right)\,\mathrm{inStream}\left(\mathrm{`port\_b.rho`}\right)\,\mathrm{true}\,\mathrm{sharpness}\right)$

(*) $\mathrm{`HeatTransfer.Functions.regRoot2`}$ is the same function as $\mathrm{`Modelica.Fluid.Utilities.regRoot2`}$. To check the details of the package and view the original documentation, which includes author and copyright information, click here.