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Tilting Pad Bearing
Tilting Pad Journal Bearings (TPJBs) are a type of hydrodynamic bearing widely used in high-performance rotating machinery, such as turbines, compressors, pumps, and electric motors. They provide critical support for rotating shafts, allowing smooth and stable operation by reducing friction and accommodating dynamic loads.
A TPJB consists of several individual bearing pads (typically 4-5), which are mounted on pivots or hinges within a circular housing. These pads are free to tilt about their pivots in response to changes in the shaft position, enabling the formation of a self-adjusting hydrodynamic film. This film, created by the lubricant flow, separates the rotating journal from the pads, minimizing metal-to-metal contact and wear.
The ability of each pad to tilt improves the stability and adaptability of the bearing compared to fixed-geometry journal bearings. This tilting mechanism allows TPJBs to adjust to varying operating conditions, such as changes in load, speed, or misalignments.
An improved Pressurized Tilting Pad Journal Bearings (PTPJBs) have been developed. These bearings use an external pressurization system to enhance performance by actively controlling the oil film pressure. MEDVIC lab has demonstrated additional benefits and provided deeper insights into the mechanics and applications of PTPJBs. Key advantages include:
1. Enhanced Load Capacity: Mehdi and T.H. Kim highlighted the ability of PTPJBs to support significantly higher loads due to the supplemental pressure, making them ideal for heavy-duty industrial applications.
2. Improved Damping Characteristics: The active pressurization system contributes to superior damping of vibrations, as demonstrated in their research. This leads to reduced shaft oscillations and greater stability, especially under dynamic loading conditions.
3. Minimized Thermal Distortion: By controlling the lubricant flow and temperature more effectiverly, PTPJBs reduce thermal gradients within the bearing, improving operational reliability.
4. Reduced Wear During Startup and Shutdown: In terms of wear during startup and shutdown, Pressurized Tilting Pad Journal Bearings(PTPJBs) provide distinct advantages. The external pressurization system ensures the formation of a sufficient oil film even at low speeds, reducing metal-to-metal contact and minimizing wear during these critical phases of operatio. This enhances the bearing's durability and reliability compared to conventional Tilting Pad Journal Bearings(TPJBs).
Fig. 1. Schematic view of Hybrid Tilting Pad Journal Bearing and Single Pad with Recess
Fig. 2. Prediction of local pressure distribution along the Pad Centerline in the Circumferential Direction underfluid static pressure, fluid dynamic pressure, hybrid conditions and comparison with Hagemann experimental results.
[1] Mehdi, S. M., Jang, K.E., and Kim, T. H. (2018), Effects of Pivot Design on Performance of Tilting Pad Journal Bearings. Tribology International, 119, pp 175-189.
[2] Mehdi, S. M., & Kim, T. H. (2022). Computational model develpment for hybrid tilting pad journal bearings lubricated with supercritical carbon dioxide. Applied Sciences, 12(3), 1320.
[3] Mehdi, S. M., Jeong, S. Y., & Kim, T. H. (2022). Influence of recess dimensions and jacking oil flow rate on the performance of tilting pad journal bearings with jacking oil mechanism. Tribology Transactions, 65(3), 405-420.
A TPJB consists of several individual bearing pads (typically 4-5), which are mounted on pivots or hinges within a circular housing. These pads are free to tilt about their pivots in response to changes in the shaft position, enabling the formation of a self-adjusting hydrodynamic film. This film, created by the lubricant flow, separates the rotating journal from the pads, minimizing metal-to-metal contact and wear.
The ability of each pad to tilt improves the stability and adaptability of the bearing compared to fixed-geometry journal bearings. This tilting mechanism allows TPJBs to adjust to varying operating conditions, such as changes in load, speed, or misalignments.
An improved Pressurized Tilting Pad Journal Bearings (PTPJBs) have been developed. These bearings use an external pressurization system to enhance performance by actively controlling the oil film pressure. MEDVIC lab has demonstrated additional benefits and provided deeper insights into the mechanics and applications of PTPJBs. Key advantages include:
1. Enhanced Load Capacity: Mehdi and T.H. Kim highlighted the ability of PTPJBs to support significantly higher loads due to the supplemental pressure, making them ideal for heavy-duty industrial applications.
2. Improved Damping Characteristics: The active pressurization system contributes to superior damping of vibrations, as demonstrated in their research. This leads to reduced shaft oscillations and greater stability, especially under dynamic loading conditions.
3. Minimized Thermal Distortion: By controlling the lubricant flow and temperature more effectiverly, PTPJBs reduce thermal gradients within the bearing, improving operational reliability.
4. Reduced Wear During Startup and Shutdown: In terms of wear during startup and shutdown, Pressurized Tilting Pad Journal Bearings(PTPJBs) provide distinct advantages. The external pressurization system ensures the formation of a sufficient oil film even at low speeds, reducing metal-to-metal contact and minimizing wear during these critical phases of operatio. This enhances the bearing's durability and reliability compared to conventional Tilting Pad Journal Bearings(TPJBs).
Fig. 1. Schematic view of Hybrid Tilting Pad Journal Bearing and Single Pad with Recess
Fig. 2. Prediction of local pressure distribution along the Pad Centerline in the Circumferential Direction underfluid static pressure, fluid dynamic pressure, hybrid conditions and comparison with Hagemann experimental results.
[1] Mehdi, S. M., Jang, K.E., and Kim, T. H. (2018), Effects of Pivot Design on Performance of Tilting Pad Journal Bearings. Tribology International, 119, pp 175-189.
[2] Mehdi, S. M., & Kim, T. H. (2022). Computational model develpment for hybrid tilting pad journal bearings lubricated with supercritical carbon dioxide. Applied Sciences, 12(3), 1320.
[3] Mehdi, S. M., Jeong, S. Y., & Kim, T. H. (2022). Influence of recess dimensions and jacking oil flow rate on the performance of tilting pad journal bearings with jacking oil mechanism. Tribology Transactions, 65(3), 405-420.