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Updated formulation for Biot number calculation #586

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71daafa
Updated formulation for Biot number calculation
krishnatejas12 Jan 19, 2026
401f4d2
fix: add explicit units lib dependency (#585)
iboyd-ansys Jan 21, 2026
0bbe17c
build(deps): bump actions/download-artifact from 6.0.0 to 7.0.0 (#579)
dependabot[bot] Jan 21, 2026
ac4e7ab
build(deps): bump actions/upload-artifact from 5.0.0 to 6.0.0 (#580)
dependabot[bot] Jan 21, 2026
0e65d0c
build(deps-dev): bump sphinxemoji from 0.3.1 to 0.3.2 (#581)
dependabot[bot] Jan 21, 2026
1b79b4d
fix: add explicit units lib dependency (#585)
iboyd-ansys Jan 21, 2026
f99cc1d
build(deps): bump actions/download-artifact from 6.0.0 to 7.0.0 (#579)
dependabot[bot] Jan 21, 2026
2c33c49
build(deps): bump actions/upload-artifact from 5.0.0 to 6.0.0 (#580)
dependabot[bot] Jan 21, 2026
6f0f02d
build(deps-dev): bump sphinxemoji from 0.3.1 to 0.3.2 (#581)
dependabot[bot] Jan 21, 2026
aa97e8b
addressed changes to be made after review
krishnatejas12 Jan 21, 2026
21e6cc2
Updated formulation for Biot number calculation
krishnatejas12 Jan 19, 2026
271f62e
addressed changes to be made after review
krishnatejas12 Jan 21, 2026
5681da9
Merge branch 'Biot_update' of github.com:ansys/pysystem-coupling into…
krishnatejas12 Jan 21, 2026
101d083
fixed miscellaneous issues
krishnatejas12 Jan 21, 2026
540f781
fixed formatting issues
krishnatejas12 Jan 21, 2026
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8 changes: 4 additions & 4 deletions .github/workflows/ci.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -181,7 +181,7 @@ jobs:
python-version: ${{ env.MAIN_PYTHON_VERSION }}

- name: Download package
uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6.0.0
uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7.0.0
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@dabrown93 dabrown93 Jan 21, 2026

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Why are all these changed? Maybe try pulling the main branch and rebasing on it to see if they go away.

with:
name: ${{ env.PACKAGE_NAME }}-artifacts
path: dist
Expand Down Expand Up @@ -264,7 +264,7 @@ jobs:
python-version: ${{ env.MAIN_PYTHON_VERSION }}

- name: Download package
uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6.0.0
uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7.0.0
with:
name: ${{ env.PACKAGE_NAME }}-artifacts
path: dist
Expand Down Expand Up @@ -326,7 +326,7 @@ jobs:
# extra_mem_top: 30000000

- name: Upload HTML Documentation
uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
with:
name: documentation-html
path: doc/_build/html
Expand Down Expand Up @@ -369,7 +369,7 @@ jobs:
steps:

- name: "Download the library artifacts from build-library step"
uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6.0.0
uses: actions/download-artifact@37930b1c2abaa49bbe596cd826c3c89aef350131 # v7.0.0
with:
name: ${{ env.PACKAGE_NAME }}-artifacts
path: ${{ env.PACKAGE_NAME }}-artifacts
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57 changes: 32 additions & 25 deletions examples/00-systemcoupling/cht_pipe.py
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Original file line number Diff line number Diff line change
Expand Up @@ -251,42 +251,49 @@
mu_fluid = 0.001 # Dynamic viscosity of fluid
cp_fluid = 4182 # Specific heat capacity of fluid
k_fluid = 0.6 # Thermal conductivity of fluid
k_solid = 1.2 # Thermal conductivity of solid
k_solid = 237 # Thermal conductivity of solid


def compute_thermo_numbers(rho, mu, cp, k_fluid, k_solid, velocity, L_c, n=0.4):
"""Compute Reynolds, Nusselt, h, and Biot numbers."""
def nusselt_number(Re, Pr, d_in, L):
# From: Bergman, T. L., Lavine, A. S., Incropera, F. P., & DeWitt, D. P. (2017).
# Fundamentals of Heat and Mass transfer (8th ed.). Wiley.
if Re >= 6000:
Nu = 0.023 * Re**0.8 * Pr ** (1 / 3)
method = "Colburn"
else:
Nu = 3.66 + (0.068 * (Re * Pr * d_in / L)) / (
1 + 0.04 * (Re * Pr * d_in / L) ** (2 / 3)
)
method = "Hausen"

def reynolds_number(rho, mu, velocity, D_h):
"""Reynolds number."""
return (rho * velocity * D_h) / mu
return Nu, method

def nusselt_number(Re, Pr, n):
"""Dittus–Boelter Nusselt number."""
return 0.023 * (Re**0.8) * (Pr**n)

def biot_number(h, L_c, k_solid):
"""Biot number."""
return h * L_c / k_solid
def compute_thermo_numbers(rho, mu, cp, k_fluid, k_solid, velocity, d_in, L, L_c):
Pr = cp * mu / k_fluid
Re = rho * velocity * d_in / mu

Pr = (cp * mu) / k_fluid
Re = reynolds_number(rho, mu, velocity, L_c)
Nu = nusselt_number(Re, Pr, n)
h = Nu * k_fluid / L_c
Bi = biot_number(h, L_c, k_solid)
# Nusselt number
Nu, correlation = nusselt_number(Re, Pr, d_in, L)

return Re, Nu, h, Bi
# Convective heat transfer coefficient
h = Nu * k_fluid / d_in

# Biot number
Bi = h * L_c / k_solid

return Re, Pr, h, Bi, correlation

Re, Nu, h, Bi = compute_thermo_numbers(
fluid_rho, mu_fluid, cp_fluid, k_fluid, k_solid, U, L_c
)

print("Reynolds Number =", Re)
print("Nusselt Number =", Nu)
print("Heat Transfer Coefficient =", h)
print("Biot Number =", Bi)
Re, Nu, h, Bi, corr = compute_thermo_numbers(
fluid_rho, mu_fluid, cp_fluid, k_fluid, k_solid, U, d_in, l, L_c
)

print(f"Reynolds number = {Re}")
print(f"Nusselt number = {Nu}")
print(f"Heat transfer coefficient h = {h} W/(m^2·K)")
print(f"Biot number = {Bi}")
print(f"Nusselt correlation used = {corr}")
# %%
# Apply stabilization if Biot number exceeds 10.
if Bi > 10:
Expand Down
4 changes: 3 additions & 1 deletion pyproject.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -71,10 +71,12 @@ doc = [
"sphinx-gallery==0.20.0",
"sphinx-notfound-page==1.1.0",
"sphinxcontrib-websupport==2.0.0",
"sphinxemoji==0.3.1",
"sphinxemoji==0.3.2",

# pyansys dependencies for sphinx gallery examples
"ansys-fluent-core==0.35.0",
# ... temporary to fix fluent runtime error:
"ansys-units==0.9.1",
"ansys-mapdl-core==0.71.3",
]
style = [
Expand Down