Faculty Profiles - HATAKENAKA Kiyoshi

Papers - HATAKENAKA Kiyoshi

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Model Expression for Simple Design of Maximum Bearing Temperature of Cylindrical Journal Bearing with Two Axial Oil Grooves Applying Deep Learning Reviewed

HATAKENAKA Kiyoshi, UCHIDA Keitaro

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 69 ( 10 ) 690 - 707 2024.10

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Thermohydrodynamic lubrication (THL) models have been applied to predict the performances of journal bearings that support industrial rotating machineries. This article aims at deriving a model expression that can easily predict the maximum bearing temperature in the THL database of cylindrical journal bearing with two-axial oil grooves, by applying deep learning (DL). The expression is given only four dimensionless bearing design variables. The DL model consists of a multi-layer perceptron with a preprocessing layer, four hidden layers, an output layer and a postprocessing layer. All nodes in adjacent layers are fully connected. Logarithmic function is employed as preprocessing function for the bearing design variables and the maximum bearing temperature, and inverse tangent function as activation function. Six nodes are arranged in each hidden layer. The dataset with the maximum bearing temperature above 0.2 is selected for the training data. Learning is continued until the maximum relative errors for the training and the validation data simultaneously fall within the criterion value. The model expression is shown to be capable of easily predicting the maximum bearing temperature quickly and with high generalization performance and is concluded to be quite useful in significantly reducing the time required to THL design of the bearing.</p>

DOI： 10.18914/tribologist.24-00004

Performance prediction of journal bearing with fluid slip regions on part of lubricated surface Reviewed

HATAKENAKA Kiyoshi, OBANA Ryoichiro

Transactions of the JSME (in Japanese) ( The Japan Society of Mechanical Engineers ) advpub ( 0 ) 24-00116 - 24-00116 2024.10

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Rotating machineries supported in journal bearings are operated at a rotational speed between the one where the minimum oil film thickness is ensured to prevent direct contact of the journal and bearing surfaces and the one where self-excited vibration occurs, while avoiding the critical speed of the rotor-bearing system. When a rotating shaft is supported in a cylindrical journal bearing, which has the simplest structure among journal bearings, the upper operational speed will be approximately twice the critical speed. In the present report, focusing on a rotating shaft supported in the bearing with fluid slip regions on part of the bearing surface, those speeds are numerically calculated by applying a hydrodynamic lubrication theory, then the effects of the fluid slip region on the range of stable operation are evaluated. It is found as follows; (1) the detachment speed of the journal from the bearing is not affected by whether or not the fluid slip regions are given, (2) the stability threshold speed is significantly enhanced when several fluid slip regions are given at intervals up to the apex of the bearing downstream from the direction of attitude angle at the detachment speed, and (3) the enhanced stability caused by the fluid slip region is attributed to a reduction in oscillating journal motion. The range of the safe operation of a rotating shaft can be significantly extended simply by giving fluid slip regions on a part of the bearing surface, without replacing complicated journal bearings or employing stabilization method such as adjusting the amount of oil supplied.</p>

DOI： 10.1299/transjsme.24-00116

Other Link： https://www.jstage.jst.go.jp/article/transjsme/90/938/90_24-00116/_pdf

Database of Thermohydrodynamic Lubrication Performance for Application to the Design of Cylindrical Journal Bearings with Two-Axial Oil Grooves Reviewed

HATAKENAKA Kiyoshi, UCHIDA Keitaro

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 69 ( 5 ) 373 - 384 2024.02

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Thermohydrodynamic lubrication (THL) models have been applied to predict the performances of journal bearings that support industrial rotating machineries. The final goal of this study is to propose a THL bearing design method of cylindrical journal bearings with two axial oil grooves by using the model expressions, which are derived from a database constructed by the THL performances and can predict the reasonably accurate bearing performances over a wide range of operating conditions and bearing specifications. In this article, an ALE (Arbitrary Lagrangian-Eulerian method)-based simplified THL model, which predicts the bearing performances from only four dimensionless numbers ―Sommerfeld number, bearing width-to-diameter ratio, Peclet number and Khonsari number ―, is employed for constructing a THL database of the bearing. In some cases, numerical oscillations concerning oil film viscosity make it impossible to obtain the numerally converged solution. However, the solution can be obtained by transforming the energy equation of the oil film so as to solve for the oil film viscosity, which results in the database for a wide range of the bearing design variables. The properties of the database are investigated and it is found necessary to derive the model expressions for the THL performances of the bearing.</p>

DOI： 10.18914/tribologist.23-00019

多領域問題としてのRD流体力～理論・解析技術の変遷～ Invited Reviewed

内海政春,田浦裕生,畠中清史,富松重行,渡邊裕輔

ターボ機械 ( ターボ機械協会 ) 52 ( 1 ) 46 - 58 2024.01

A New Design Chart Method of Cylindrical Bearings Based on a Simplified Thermohydrodynamic Lubrication Model Invited Reviewed

HATAKENAKA Kiyoshi, HONDA Aoi

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 68 ( 10 ) 706 - 709 2023.10

Thermo-hydrodynamic lubrication analysis of journal bearings using a simplified THL model and prediction of onset speed of instability (Application of adiabatic boundary condition to the journal side) Reviewed

SOGO Makoto, INOUE Tsuyoshi, HATAKENAKA Kiyoshi

Transactions of the JSME (in Japanese) ( The Japan Society of Mechanical Engineers ) 89 ( 924 ) 23-00068 - 23-00068 全21ページ 2023.08

Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Journal bearings are an important mechanical element of rotating machines and support the rotor system by oil film reaction forces. As rotational speeds increase, the shear heat of the oil film causes a significant temperature distribution on the journal surface. As a result, bending of the shaft occurs and vibration modes called Morton effect are generated. The Thermo Hydrodynamic Lubrication (THL) model is used for analyzing of lubricant, and one of the authors has modified and applied it as a simple unsteady model to efficiently analyze the temperature, viscosity, and pressure distribution of the oil film , maintaining computational accuracy. In this paper, the simplified THL model is modified with the boundary condition that both the bearing and journal are adiabatic (ADIADI) in order to construct an accurate and efficient analytical model of the Morton effect in the rotor system. The journal vibration is assumed to be small, and dynamic coefficients of journal bearing are derived considering the temperature distribution. Eigenvalue analysis is performed using these dynamic coefficients to predict the onset speed of instability of the rotor system. The validity of the eigenvalue analysis is verified by direct numerical integration simulation.</p>

DOI： 10.1299/transjsme.23-00068

Other Link： https://www.jstage.jst.go.jp/article/transjsme/89/924/89_23-00068/_pdf

Time History of Maximum Bearing Temperature Based on a Simplified Thermohydrodynamic Lubrication Theory Reviewed International journal

Hatakenaka Kiyoshi

Tribology Online ( Japanese Society of Tribologists ) 18 ( 2 ) 53 - 63 2023.06

Authorship：Lead author,　Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

<p>An overshoot phenomenon of bearing temperature in hydrodynamic journal bearings may be observed during a sudden start-up experiment. This phenomenon implies that the maximum bearing temperature in acceleration operation may exceed the predicted one which can be predicted accurately by applying a state-of-the-art steady state thermohydrodynamic lubrication (THL) model. This paper presents the maximum bearing temperature including the one during acceleration operation by using a simplified THL model that is newly proposed for a transient THL analysis. It is found that the overshooted temperature can be qualitatively predicted by using the transient THL model that incorporates properly the interaction between the motion of journal center and the viscous dissipation, even if it is a simple model. Next, the transient temperature during slow acceleration operation and also those toward higher dimensional steady state journal rotational speed are calculated and they are found to be in qualitative agreement with the measurements. The oil film characteristics such as oil film pressure, temperature and thickness after reaching the steady state equilibrium do not depend on the value of initial journal eccentricity ratio in the transient analysis. However, when the values are different, the characteristics immediately after starting rotation change largely. In the case of the value 1.00, it is found to give a prediction that agrees qualitatively with the characteristics measured in the experiment.</p>

DOI： 10.2474/trol.18.53

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85163443099&origin=inward

Reduction of Oil Film Width and Bush Driving Torque in High Speed Journal Bearing Reviewed

HATAKENAKA Kiyoshi, KOZUKI Yasushi

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 68 ( 5 ) 352 - 362 2023.05

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Floating bush journal bearings are widely used to support small-sized high-speed rotating machinery. When the journal rotational speed exceeds a stability threshold speed, the bearing shows self-excited vibration, which could be disappeared as the speed further increases and the bush rotational speed levels off in the case of low supply pressure. The peculiar phenomenon can be explained qualitatively by applying the hydrodynamic lubrication model with the axial oil film rupture being considered. However, the predictions are in quantitatively poor agreement with the measurements. In the present article, intending to obtain experimental results that would be useful for future improvement of the theoretical model, the authors experimentally observe the oil film by using a test apparatus of a cylindrical journal bearing that is equivalent to the inner oil film of a high-speed floating bush journal bearing. The width of the oil film is shown to gradually reduce with an increase in journal rotational speed due to air inflow into the bearing clearance, which results in the measured bush driving torque definitely lower than the theoretical one calculated from Petroff's formula. The ratio of the measured torque to the theoretical one is found to decrease with increasing journal rotational speed although the ratio does not simply decrease in proportion to the observed oil film width.</p>

DOI： 10.18914/tribologist.22-00030

熱流体潤滑理論を応用したジャーナル軸受の性能解析と設計 Invited Reviewed

畠中清史

ターボ機械 ( ターボ機械協会 ) 51 ( 1 ) 25 - 36 2023.01

A simplified thermohydrodynamic lubrication model for application to the design of cylindrical journal bearings with two-axial oil grooves Reviewed

Kiyoshi HATAKENAKA, Keitaro Uchida

Transactions of the JSME (in Japanese) ( The Japan Society of Mechanical Engineers ) 88 ( 915 ) 22-00234 - 22-00234 全17ページ 2022.11

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Thermohydrodynamic lubrication (THL) models have been applied to predict the performances of journal bearings that support industrial rotating machineries. The final goal of this study is to propose a THL bearing design method of cylindrical journal bearings with two-axial oil grooves by using the model expressions, which are derived from a database constructed by the THL predictions and can predict the reasonably accurate bearing performances over a wide range of operating conditions and bearing specifications. In the present article, after the previous simplified model, which predicts the bearing performances from only four dimensionless numbers — Sommerfeld number, bearing width-to-diameter ratio, Peclet number and Khonsari number, is shown to poorly predict the performances, a simplified THL model is newly proposed for the database of the bearing performances. This model is derived by modifying the precedent high-accuracy THL model and predicts the bearing performances from the same four dimensionless numbers as the previous simplified model. Compared with some measurements in test rigs of the bearings, the model proposed is found to predict more reasonably accurate performances of the bearing under fully lubricated conditions than the previous simplified model. It is concluded that the new model is appropriate to the database for the simple easy and straightforward bearing design.</p>

DOI： 10.1299/transjsme.22-00234

Other Link： https://www.jstage.jst.go.jp/article/transjsme/88/915/88_22-00234/_pdf

A New Design Method of Cylindrical Bearings Based on a Simplified Thermohydrodynamic Lubrication Model Reviewed International journal

Kiyoshi HATAKENAKA, Aoi HONDA

Tribology Online ( Japanese Society of Tribologists ) 17 ( 3 ) 175 - 195 2022.09

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

<p>This paper proposes a new THL bearing design method based on an improved version of a precedent method. The precedent method used a model expression prepared in advance to easily and quickly find a crucial predicted data of the maximum bearing temperature. Three expressions were prepared for three different values of journal eccentricity ratio, 0.25, 0.50, and 0.75. Which one of the three should be used was determined, based on the preliminarily obtained value of journal eccentricity ratio derived from the initially analysis and <i>t</i>–test, for the crucial temperature for any value of journal eccentricity ratio. Furthermore, the new expression explicitly includes the four well-known dimensionless numbers used in THL analysis, that is, Sommerfeld number, bearing width-to-dimeter ratio, Peclet number and Khonsari number. The model expressions for other bearing characteristic performances were obtained in the same way. Compared with some measurements in test rigs of cylindrical bearings, the new improved method is confirmed to predict reasonably accurate bearing performances of cylindrical bearings faster and more easily than the precedent method over a wide range of operating conditions.</p>

DOI： 10.2474/trol.17.175

DOI： 10.2474/trol.17.175

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85140405454&origin=inward

Application of Particle Simulation Method to Oil Film Viscous Torque of Concentric Journal Bearings Reviewed

HATAKENAKA Kiyoshi, TERATOKO Kaito

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 67 ( 4 ) 299 - 312 2022.04

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Floating bush journal bearings are widely used to support small-sized high-speed rotating machinery. When the oil-supplying pressure is low, the bearings show peculiar phenomena such as leveling-off of bush rotational speed and disappearance of oil whip event. Although the phenomena can be explained qualitatively by applying the hydrodynamic lubrication model with the axial oil film rupture being considered, the predictions are in quantitatively poor agreement with the measurements. The key to improving the discrepancy lies in numerically calculating the steady-state value of bush driving torque due to viscous force. This study aims at obtaining the value by adopting a moving particle simulation (MPS) method. Firstly, the governing equations based on the conventional isoviscous hydrodynamic lubrication theory are modified such that the MPS method can be applied to the concentric inner oil film of the bearing. Next, they are solved by using the least squares moving particle semi-implicit (LSMPS) scheme coupled with arbitrary Lagrangian-Eulerian (ALE) method. Lastly, the steady-state values of the bush driving torque are calculated for a range of the bearing design parameters and are found to be in good agreement with the theoretical value obtained from Petroff's law.</p>

DOI： 10.18914/tribologist.21-00019

Other Link： http://id.ndl.go.jp/bib/032129477

A New Design Method of Cylindrical Bearings Based on a Simplified Thermohydrodynamic Lubrication Model Reviewed

HATAKENAKA Kiyoshi, HONDA Aoi

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 66 ( 7 ) 548 - 569 2021.07

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>This paper proposes a new THL bearing design method based on an improved version of a precedent method. The precedent method used a model expression prepared in advance to easily and quickly find a crucial predicted data of the maximum bearing temperature. Three expressions were prepared for three different values of journal eccentricity ratio, 0.25, 0.5, and 0.75. Which one of the three should be used was determined, based on the preliminarily obtained value of journal eccentricity ratio derived from the initially assumed bearing specifications. Two dimensionless temperature-rise parameters <i>κ</i><sub>1 </sub>and <i>κ</i><sub>2 </sub>were introduced for the common variables of the expression. On the other hand, the new improved method uses a single expression, which is obtained by applying multiple regression analysis and <i>t</i>-test, for the crucial temperature for any value of journal eccentricity ratio. Furthermore, the new expression explicitly includes the four well-known dimensionless numbers used in THL analysis, that is, Sommerfeld number, bearing width-to-dimeter ratio, Peclet number and Khonsari number. The model expressions for other bearing characteristic performances were obtained in the same way. Compared with some measurements in test rigs of cylindrical bearings, the new improved method is confirmed to predict reasonably accurate bearing performances of cylindrical bearings faster and more easily than the precedent method over a wide range of operating conditions.</p>

DOI： 10.18914/tribologist.20-00016

Other Link： https://ci.nii.ac.jp/naid/130008037345

Effect of Analytical Model of Top Foil Displacement on Predicted Maximum Load Carrying Capacity of Bump Foil Journal Bearings (Part 2):―Application of Isoparametric Shell Element― Reviewed

HATAKENAKA Kiyoshi

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 66 ( 5 ) 372 - 383 2021.05

Authorship：Lead author,　Last author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Bump foil journal bearings are prospective applicants that can support a small-sized rotor of high-speed rotating machinery. The performance characteristics of the bearings are predicted by using a model bearing. When the air film thickness can be assumed to be uniform in the axial direction, a finite element (FE) model using curved beam element is appropriate to be applied in analyzing the displacement of bearing surface which is referred to as top foil. On the other hand, the top foil need be replaced with a thin shell in order to predict the performances of the bearing that has non-uniform air film thickness in the direction. In this study, an isoparametric shell element, which can couple the membrane and the bending effects of top foil, is introduced into the deformation analysis instead of a plate shell element adopted in the previous paper. The replacement of FE model is found to have a large influence on the bearing performance because of the change in the air film characteristics. It is concluded that the isoparametric shell element is appropriate in predicting the performance of the bearing that has non-uniform air film thickness in the axial direction.</p>

DOI： 10.18914/tribologist.20-00015

Other Link： https://ci.nii.ac.jp/naid/130008000345

Time History of Maximum Bearing Temperature Based on a Simplified Thermohydrodynamic Lubrication Theory Reviewed

HATAKENAKA Kiyoshi

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 66 ( 5 ) 384 - 396 2021.05

Authorship：Lead author,　Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal)

<p>An overshoot phenomenon of bearing temperature in hydrodynamic journal bearings may be observed during a sudden start-up experiment. This phenomenon implies that the maximum bearing temperature in acceleration operation may exceed the predicted one which can be predicted accurately by applying a state-of-the-art steady-state thermohydrodynamic lubrication (THL) model. This paper presents the maximum bearing temperature including the one during acceleration operation by using a simplified THL model that is newly proposed for a transient THL analysis. It is found that the overshooted temperature can be qualitatively predicted by using the transient THL model that incorporates properly the interaction between the motion of journal center and the viscous dissipation, even if it is a simple model. Next, the transient temperature during slow acceleration operation and also those toward higher dimensional steady-state journal rotational speed are calculated and they are found to be in qualitative agreement with the measurements. The oil film characteristics such as oil film pressure, temperature and thickness after reaching the steady-state equilibrium do not depend on the value of initial journal eccentricity ratio in the transient analysis. However, when the values are different, the characteristics immediately after starting rotation change largely. In the case of the value 1.00, it is found to give a prediction that agrees qualitatively with the characteristics measured in the experiment.</p>

DOI： 10.18914/tribologist.20-00017

Other Link： https://ci.nii.ac.jp/naid/130008000334

A New Design Chart Method of Journal Bearings Based on a Simplified Thermohydrodynamic Lubrication Theory Reviewed

Kiyoshi Hatakenaka

Tribology Transactions 63 ( 5 ) 935 - 945 2020.10

A New THL Model for High Accuracy of Predicted Journal Surface Temperature Reviewed

Hatakenaka Kiyoshi, Baba Yoshitaka, Kameyama Yuki

Tribology Online ( Japanese Society of Tribologists ) 15 ( 4 ) 194 - 200 2020.07

Authorship：Lead author Language：English Publishing type：Research paper (scientific journal)

<p>A thermo-hydrodynamic lubrication (THL) theory is applied to journal bearings that support large-sized high-speed rotary machineries and it is confirmed that the maximum pad surface temperature under operation is below an allowable limit value. The temperature predicted by the traditional THL model is in good agreement with the measurement. However, the predicted journal surface temperature is not comparable with the measurement. In the present paper, it is firstly shown that the amount of heat, which is generated by the shear flow in the oil film and is discharged out of the film, is evaluated appropriately in the film near the pad surface while it is evaluated excessively in the film near the journal surface. Secondly, a new THL model is proposed that the oil film temperature near the pad surface and the temperature near the journal surface are obtained independently, that is, the conventional energy equation for the oil film is solved for the former temperature while the equation described in the relative coordinate system with the journal surface as the reference one is used for the latter temperature. Lastly, it is shown that the THL model can predict the journal surface temperature comparable with the measurement without deteriorating the accuracy of the predicted maximum pad surface temperature.</p>

DOI： 10.2474/trol.15.194

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85090916908&origin=inward

Effect of Analytical Model of Top Foil Displacement on Predicted Maximum Load Carrying Capacity of Bump Foil Journal Bearings (Part 1):―Application of Plate Shell Element― Reviewed

HATAKENAKA Kiyoshi

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 64 ( 10 ) 626 - 635 2019.10

Authorship：Lead author,　Last author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Bump foil journal bearings are prospective applicants that can support a small-sized rotor of high-speed rotary machinery. Some model bearings are used in predicting the characteristic performances of the bearings. In the previous study, the finite element (FE) method that adopted a curved-beam element was applied in analyzing the displacement of the bearing surface that is called as top foil. However, the model assumes that the air film thickness in the axial direction is constant, so the performance of foil journal bearings that has uneven air film thickness in the direction cannot be obtained. In this study, the top foil is assumed to be a thin shell. The displacement is analyzed by replacing the curved-beam element to a plate shell element. Although the replacement of the FE model is found to have a large influence on the performances, this is because the shell model cannot couple the membrane and the bending effects. It is concluded that the shell model is inappropriate to the prediction of the bearing performance and should be replaced to other type of shell model that can couple the two effects.</p>

DOI： 10.18914/tribologist.19-00008

Other Link： https://ci.nii.ac.jp/naid/130007728642

A New THL Model for High Accuracy of Predicted Journal Surface Temperature Reviewed

HATAKENAKA Kiyoshi, BABA Yoshitaka, KAMEYAMA Yuki

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 63 ( 5 ) 360 - 367 2018.05

Authorship：Lead author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>A thermo-hydrodynamic lubrication (THL) theory is applied to journal bearings that support large-sized high-speed rotary machineries and it is confirmed that the maximum pad surface temperature under operation is below an allowable limit value. The temperature predicted by the traditional THL model is in good agreement with the measurement. However, the predicted journal surface temperature is not comparable with the measurement. In the present paper, it is firstly shown that the amount of heat, which is generated by the shear flow in the oil film and is discharged out of the film, is evaluated appropriately in the film near the pad surface while it is evaluated excessively in the film near the journal surface. Secondly, a new THL model is proposed that the oil film temperature near the pad surface and the temperature near the journal surface are obtained independently, that is, the conventional energy equation for the oil film is solved for the former temperature while the equation described in the relative coordinate system with the journal surface as the reference one is used for the latter temperature. Lastly, it is shown that the THL model can predict the journal surface temperature comparable with the measurement without deteriorating the accuracy of the predicted maximum pad surface temperature.</p>

DOI： 10.18914/tribologist.17-00024

Other Link： https://ci.nii.ac.jp/naid/130006503702

A New THL Model with Non-Traditional Heat Transfer Model Incorporated Reviewed

HATAKENAKA Kiyoshi

JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS ( Japanese Society of Tribologists ) 63 ( 4 ) 294 - 302 2018.04

Authorship：Lead author,　Last author,　Corresponding author Language：Japanese Publishing type：Research paper (scientific journal)

<p>Thermo-hydrodynamic lubrication (THL) models have been applied at the design stage of large-sized high-speed rotary machineries to confirm that the maximum surface temperature of sliding bearing, such as tilting pad journal bearing, under operation is below the upper limit. A single common value of heat transfer coefficient is given between the environment and the five surfaces other than the lubricating one of each pad regardless of operating conditions and/or bearing specifications in the traditional THL model, while a new THL model is proposed with non-traditional heat transfer model incorporated. In this model, the value of locally distributed heat transfer coefficient is determined depending on the operation conditions and/or the bearing specifications. Using the model, it is unnecessary to determine the heat transfer coefficient by an unreasonable estimation, and it is found that the predicted maximum pad surface temperature and also the distribution of pad surface temperature are in good agreement with the measurements.</p>

DOI： 10.18914/tribologist.17-00022

Other Link： https://ci.nii.ac.jp/naid/130006337904

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