Computational Model Development for Hybrid Tilting Pad Journal Bearings Lubricated with Supercritical Carbon Dioxide
Fluid film bearings lubricated with supercritical carbon dioxide (sCO<sub>2</sub>) eliminate the infrastructural requirement for oil lubricant supply and sealing in turbomachinery for sCO<sub>2</sub> power systems. However, sCO<sub>2</sub>’s thermohydrodynamic pro...
| Main Authors: | , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-01-01
|
| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/12/3/1320 |
| _version_ | 1797489199353430016 |
|---|---|
| author | Syed Muntazir Mehdi Tae Ho Kim |
| author_facet | Syed Muntazir Mehdi Tae Ho Kim |
| author_sort | Syed Muntazir Mehdi |
| collection | DOAJ |
| description | Fluid film bearings lubricated with supercritical carbon dioxide (sCO<sub>2</sub>) eliminate the infrastructural requirement for oil lubricant supply and sealing in turbomachinery for sCO<sub>2</sub> power systems. However, sCO<sub>2</sub>’s thermohydrodynamic properties, which depend on pressure and temperature, pose a challenge, particularly with computational model development for such bearings. This study develops a computational model for analyzing sCO<sub>2</sub>-lubricated tilting pad journal bearings (TPJBs) with external pressurization. Treating sCO<sub>2</sub> as a real gas, the Reynolds equation for compressible turbulent flows solves the pressure distribution using the finite element method, and the Newton−Raphson method determines the static equilibrium position by simultaneously calculating forces, moments, flow rates of externally pressurized sCO<sub>2</sub>, and pressure drop due to flow inertia. The finite difference method solves the energy equation for temperature distribution. The density and viscosity of sCO<sub>2</sub> are converged using the successive substitution method. The obtained predictions agree with the previous and authors’ computational fluid dynamics predictions, thus validating the developed model. Hybrid lubrication increases the minimum film thickness and stiffness up to 80% and 65%, respectively, and decreases the eccentricity ratio by up to 65% compared to those of pure hydrodynamic TPJB, indicating significant improvement in the load capacity. The bearing performance is further improved with increasing sCO<sub>2</sub> supply pressure. |
| first_indexed | 2024-03-10T00:13:07Z |
| format | Article |
| id | doaj.art-6d5b9ef332a340d0a12c3e96981a0b9b |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T00:13:07Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-6d5b9ef332a340d0a12c3e96981a0b9b2023-11-23T15:55:39ZengMDPI AGApplied Sciences2076-34172022-01-01123132010.3390/app12031320Computational Model Development for Hybrid Tilting Pad Journal Bearings Lubricated with Supercritical Carbon DioxideSyed Muntazir Mehdi0Tae Ho Kim1Department of Mechanics and Design, Kookmin University, Seoul 02707, KoreaSchool of Mechanical Engineering, Kookmin University, Seoul 02707, KoreaFluid film bearings lubricated with supercritical carbon dioxide (sCO<sub>2</sub>) eliminate the infrastructural requirement for oil lubricant supply and sealing in turbomachinery for sCO<sub>2</sub> power systems. However, sCO<sub>2</sub>’s thermohydrodynamic properties, which depend on pressure and temperature, pose a challenge, particularly with computational model development for such bearings. This study develops a computational model for analyzing sCO<sub>2</sub>-lubricated tilting pad journal bearings (TPJBs) with external pressurization. Treating sCO<sub>2</sub> as a real gas, the Reynolds equation for compressible turbulent flows solves the pressure distribution using the finite element method, and the Newton−Raphson method determines the static equilibrium position by simultaneously calculating forces, moments, flow rates of externally pressurized sCO<sub>2</sub>, and pressure drop due to flow inertia. The finite difference method solves the energy equation for temperature distribution. The density and viscosity of sCO<sub>2</sub> are converged using the successive substitution method. The obtained predictions agree with the previous and authors’ computational fluid dynamics predictions, thus validating the developed model. Hybrid lubrication increases the minimum film thickness and stiffness up to 80% and 65%, respectively, and decreases the eccentricity ratio by up to 65% compared to those of pure hydrodynamic TPJB, indicating significant improvement in the load capacity. The bearing performance is further improved with increasing sCO<sub>2</sub> supply pressure.https://www.mdpi.com/2076-3417/12/3/1320tilting-pad journal bearinghybrid lubricationsupercritical carbon dioxideload capacity |
| spellingShingle | Syed Muntazir Mehdi Tae Ho Kim Computational Model Development for Hybrid Tilting Pad Journal Bearings Lubricated with Supercritical Carbon Dioxide Applied Sciences tilting-pad journal bearing hybrid lubrication supercritical carbon dioxide load capacity |
| title | Computational Model Development for Hybrid Tilting Pad Journal Bearings Lubricated with Supercritical Carbon Dioxide |
| title_full | Computational Model Development for Hybrid Tilting Pad Journal Bearings Lubricated with Supercritical Carbon Dioxide |
| title_fullStr | Computational Model Development for Hybrid Tilting Pad Journal Bearings Lubricated with Supercritical Carbon Dioxide |
| title_full_unstemmed | Computational Model Development for Hybrid Tilting Pad Journal Bearings Lubricated with Supercritical Carbon Dioxide |
| title_short | Computational Model Development for Hybrid Tilting Pad Journal Bearings Lubricated with Supercritical Carbon Dioxide |
| title_sort | computational model development for hybrid tilting pad journal bearings lubricated with supercritical carbon dioxide |
| topic | tilting-pad journal bearing hybrid lubrication supercritical carbon dioxide load capacity |
| url | https://www.mdpi.com/2076-3417/12/3/1320 |
| work_keys_str_mv | AT syedmuntazirmehdi computationalmodeldevelopmentforhybridtiltingpadjournalbearingslubricatedwithsupercriticalcarbondioxide AT taehokim computationalmodeldevelopmentforhybridtiltingpadjournalbearingslubricatedwithsupercriticalcarbondioxide |