接入AMESim help文档与PNVO流量诊断

tests/test_amesim_pneumatic_components.py

@@ -137,6 +137,17 @@ class AmesimPneumaticComponentsTest(unittest.TestCase):
         self.assertAlmostEqual(derivative.m, 0.0)
         self.assertAlmostEqual(derivative.U, -props.p * 2.0e-6)
 
+    def test_orifice_effective_area_clamps_opening(self) -> None:
+        orifice = AmesimPneumaticOrifice.from_mm2(
+            name="pn_variable_orifice",
+            area_mm2=78.5,
+            opening=1.4,
+        )
+        self.assertAlmostEqual(orifice.effective_area, 78.5e-6)
+
+        orifice.opening = -0.25
+        self.assertAlmostEqual(orifice.effective_area, 0.0)
+
     def test_orifice_returns_signed_mass_flow(self) -> None:
         orifice = AmesimPneumaticOrifice.from_mm2(
             name="pn_orifice_18",