Add Thermo-Hydro-Dynamic Tilting Pad Thrust Bearing Implementation

[gsabinoo]

Summary

This PR introduces a implementation of a Thermo-Hydro-Dynamic (THD) Tilting Pad Thrust Bearing class (ThrustPad). The implementation solves the Reynolds equation coupled with the energy equation to calculate pressure and temperature fields, equilibrium positions, and dynamic coefficients for tilting pad thrust bearings.

Key Features

Core Functionality

• Coupled THD Analysis: Simultaneous solution of Reynolds equation (pressure field) and energy equation (temperature field)
• Temperature-Dependent Viscosity: Exponential viscosity model considering thermal effects
• Equilibrium Position Calculation: Automatic determination of bearing operating position or analysis with imposed conditions
• Dynamic Coefficients: Calculation of stiffness (kzz) and damping (czz) coefficients using perturbation method
• Multiple Operating Frequencies: Support for analysis at multiple rotational speeds

Visualization & Analysis

• 3D Surface Plots: Pressure and temperature field visualization using Plotly
• 2D Contour Plots: Detailed field analysis with interpolated contours
• Results Tables: Formatted output of key bearing parameters and coefficients
• Comparison Tables: Multi-frequency coefficient comparison

Technical Implementation

Class Structure

class ThrustPad(BearingElement):
    """Thermo-Hydro-Dynamic (THD) Tilting Pad Thrust Bearing"""

Key Parameters

• Geometric: Inner/outer radius, pivot radius, arc length, angular position
• Operating: Oil temperature, lubricant properties, rotational frequency, axial load
• Numerical: Mesh resolution (n_theta, n_radial), convergence tolerances
• Mode: Equilibrium calculation vs. imposed conditions

Files Modified/Added

New Files

• ross/bearings/thrust_pad.py: Main implementation
• ross/tests/test_thrust_pad.py: Test suite for thrust bearing implementation

Usage Example

from ross.bearings.thrust_pad import ThrustPad, thrust_pad_example
from ross.units import Q_

# Create bearing instance
bearing = ThrustPad(
    n=1,
    pad_inner_radius=Q_(1150, "mm"),
    pad_outer_radius=Q_(1725, "mm"),
    pad_pivot_radius=Q_(1442.5, "mm"),
    pad_arc_length=Q_(26, "deg"),
    angular_pivot_position=Q_(15, "deg"),
    oil_supply_temperature=Q_(40, "degC"),
    lubricant="ISOVG68",
    n_pad=12,
    n_theta=10,
    n_radial=10,
    frequency=Q_([90], "RPM"),
    equilibrium_position_mode="calculate",
    fzs_load=13.320e6,
    radial_inclination_angle=Q_(-2.75e-04, "rad"),
    circumferential_inclination_angle=Q_(-1.70e-05, "rad"),
    initial_film_thickness=Q_(0.2, "mm"),
    print_result=True
)

# Or use the pre-configured example
bearing = thrust_pad_example()

[jguarato]

Well-structured PR. I didn't find anything that needs to be changed related to code formatting.

[codecov-commenter]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.37%. Comparing base (07a5a63) to head (cfb5533).
⚠️ Report is 275 commits behind head on main.
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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1210      +/-   ##
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- Coverage   82.91%   76.37%   -6.54%     
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  Files          39       39              
  Lines        8247     9720    +1473     
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+ Hits         6838     7424     +586     
- Misses       1409     2296     +887     

Files with missing lines	Coverage Δ
ross/bearings/thrust_pad.py	90.95% <ø> (ø)

... and 3 files with indirect coverage changes

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[jguarato]

The ThrustPad class needs to be imported in __ init__.py