Improving HexBlock getWettedPerimeter calculation

armi/reactor/blocks.py

@@ -27,19 +27,20 @@
 
 import numpy
 
+from armi import nuclideBases
 from armi import runLog
 from armi.bookkeeping import report
-from armi import nuclideBases
 from armi.physics.neutronics import GAMMA
 from armi.physics.neutronics import NEUTRON
-from armi.reactor.components import basicShapes
 from armi.reactor import blockParameters
 from armi.reactor import components
-from armi.reactor.components.basicShapes import Hexagon, Circle
 from armi.reactor import composites
 from armi.reactor import geometry
 from armi.reactor import grids
 from armi.reactor import parameters
+from armi.reactor.components import basicShapes
+from armi.reactor.components.basicShapes import Hexagon, Circle
+from armi.reactor.components.complexShapes import Helix
 from armi.reactor.flags import Flags
 from armi.reactor.parameters import ParamLocation
 from armi.utils import densityTools
@@ -2211,11 +2212,19 @@ def getWettedPerimeter(self):
                 6 * c.getDimension("ip") / math.sqrt(3) if c else 0.0
             )
 
-        # solid circle = od * pi
-        # NOTE: since these are pin components, multiply by the number of pins
+        # solid circle = NumPins * pi * (Comp Diam + Wire Diam)
         wettedPinPerimeter = 0.0
         for c in wettedPinComponents:
-            wettedPinPerimeter += c.getDimension("od") if c else 0.0
+            correctionFactor = 1.0
+            if isinstance(c, Helix):
+                # account for the helical wire wrap
+                correctionFactor = numpy.hypot(
+                    1.0,
+                    math.pi
+                    * c.getDimension("helixDiameter")
+                    / c.getDimension("axialPitch"),
+                )
+            wettedPinPerimeter += c.getDimension("od") * correctionFactor
         wettedPinPerimeter *= self.getNumPins() * math.pi
 
         # hollow circle = (id + od) * pi

armi/reactor/tests/test_blocks.py

@@ -747,7 +747,7 @@ def test_getTotalMass(self):
         self.assertAlmostEqual(cur, ref, places=places)
 
     def test_replaceBlockWithBlock(self):
-        r"""Tests conservation of mass flag in replaceBlockWithBlock."""
+        """Tests conservation of mass flag in replaceBlockWithBlock."""
         block = self.block
         ductBlock = block.__class__("duct")
         ductBlock.add(block.getComponent(Flags.COOLANT, exact=True))
@@ -771,13 +771,24 @@ def test_replaceBlockWithBlock(self):
 
     def test_getWettedPerimeter(self):
         cur = self.block.getWettedPerimeter()
+
+        wire = self.block.getComponent(Flags.WIRE)
+        correctionFactor = numpy.hypot(
+            1.0,
+            math.pi
+            * wire.getDimension("helixDiameter")
+            / wire.getDimension("axialPitch"),
+        )
+        wireDiameter = wire.getDimension("od") * correctionFactor
+
         ref = math.pi * (
-            self.block.getDim(Flags.CLAD, "od") + self.block.getDim(Flags.WIRE, "od")
+            self.block.getDim(Flags.CLAD, "od") + wireDiameter
         ) * self.block.getDim(Flags.CLAD, "mult") + 6 * self.block.getDim(
             Flags.DUCT, "ip"
         ) / math.sqrt(
             3
         )
+
         self.assertAlmostEqual(cur, ref)
 
     def test_getFlowAreaPerPin(self):

doc/release/0.2.rst

@@ -15,6 +15,7 @@ What's new in ARMI
 Bug fixes
 ---------
 #. Changed units.FLOAT_DIMENSION_DECIMALS from 10 to 8 (`PR#1183 <https://github.com/terrapower/armi/pull/1183>`_)
+#. Improved ``HexBlock.getWettedPerimeter()`` to include wire. (`PR#1299 <https://github.com/terrapower/armi/pull/1299>`_)
 #. Fixed a bug in the ISOTXS file name used for snapshots. (`PR#1277 <https://github.com/terrapower/armi/pull/1277>`_)
 #. Fix a bug in uniform mesh decusping when assemblies of same type have drastically different height. (`PR#1282 <https://github.com/terrapower/armi/pull/1282>`_)
 #. Sort components on representativeBlock for consistency check. (`PR#1275 <https://github.com/terrapower/armi/pull/1275>`_)