The Orifice component calculates the mass flow rate through an orifice which depends on the upstream and downstream pressures, respectively. This component will not be valid to use when the pressure ratio becomes unity. To avoid numerical problems, the Orifice ISO 6358 component would be more suitable to use in such cases.

	Formulation Approaches
	Two approaches are taken for the formulation of the flow equation inside the component. When the boolean parameter $\mathrm{Use} \mathrm{Perry}\'s \mathrm{flow} \mathrm{coeff}$ is true, Perry's relationship to calculate the coefficient of discharge as a function of pressure drop is used instead of a constant $\mathrm{C\_\_d}$.

$$\begin{gathered} p\=p_A-p_B \\ \mathrm{hflow\_\_x} \= \mathrm{inStream}\left(\mathrm{portx}\cdot \mathrm{hflow}\right) \end{gathered}$$

Orifice Gas Equations$$

$$\begin{gathered} \mathrm{mflow} \= A\cdot \mathrm{C\_\_d}\cdot \mathrm{p\_\_1}\cdot \sqrt{\frac{2}{R\cdot \mathrm{T\_\_env}}}\{\begin{array}{cc}\frac{\mathrm{\γ}}{\mathrm{\γ}-1}\cdot {\left(\frac{\mathrm{p\_\_2}}{\mathrm{p\_\_1}}\right)}^{\left(\frac{2}{\mathrm{\γ}}\right) }- {\left(\frac{\mathrm{p\_\_2}}{\mathrm{p\_\_1}}\right)}^{\frac{\left(\mathrm{\γ}\+1\right)}{\mathrm{\γ}}}& \frac{\mathrm{p2}}{\mathrm{p1}}\ge \mathrm{b\_\_}\\ {\left(\frac{2}{\mathrm{\γ}\+1}\right)}^{\frac{1}{\left(\mathrm{\γ}-1\right)}}\cdot \sqrt{\frac{\mathrm{\γ}}{\mathrm{\γ}\+1}}& \frac{\mathrm{p\_\_2}}{\mathrm{p\_\_1}}\le b\\ & \end{array} \\ \mathrm{Where}\, \mathrm{p\_\_1} \to \mathrm{Upstream} \mathrm{pressure}\, \mathrm{p\_\_2} \to \mathrm{Downstream} \mathrm{pressure} \end{gathered}$$When $\mathrm{Use} \mathrm{Perry}\'s \mathrm{flow} \mathrm{coeff}$ is true

$\mathrm{Ar}\= 0.8414 -0.1002\cdot \left(\frac{\mathrm{p\_\_2}}{\mathrm{p\_\_1}}\right) \+ 0.8415\cdot \left(\frac{\mathrm{p\_\_2}}{\mathrm{p\_\_1}}\right) 2 -3.9{\left(\frac{\mathrm{p\_\_2}}{\mathrm{p\_\_1}}\right)}^3 \+ 4.6001\cdot {\left(\frac{\mathrm{p\_\_2}}{\mathrm{p\_\_1}}\right)}^4 -1.6827\cdot {\left(\frac{\mathrm{p\_\_2}}{\mathrm{p\_\_1}}\right)}^5$