THD Analysis of High Speed Heavily Loaded Journal Bearings Including Thermal Deformation, Mass Conserving Cavitation, and Turbulent Effects

1999 ◽  
Vol 122 (3) ◽  
pp. 597-602 ◽  
Author(s):  
Chao Zhang ◽  
Zixia Yi ◽  
Zhiming Zhang
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
High Speed ◽  
Thermal Deformation ◽  
Numerical Solutions ◽  
Journal Bearings ◽  
Eccentricity Ratio ◽  
Temperature Distributions ◽  
Theoretical Results

Theoretical and experimental THD analyses of high speed heavily loaded journal bearings are presented. Numerical solutions include thermal deformation, mass conserving cavitation and turbulent effects. The pressure and temperature distributions, the eccentricity ratio, and the flow rate are measured. Agreement between theoretical results and experimental data is satisfactory. [S0742-4787(00)00803-1]

scholarly journals Design and thermal characteristic analysis of motorized spindle cooling system

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110208
Author(s):  
Yuan Zhang ◽  
Lifeng Wang ◽  
Yaodong Zhang ◽  
Yongde Zhang
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Thermal Deformation ◽  
Cooling System ◽  
Thermal Characteristic ◽  
Water Flow Rate ◽  
Thermal Characteristics ◽  
Characteristic Analysis ◽  
Motorized Spindle ◽  
Experiment And Simulation

The thermal deformation of high-speed motorized spindle will affect its reliability, so fully considering its thermal characteristics is the premise of optimal design. In order to study the thermal characteristics of high-speed motorized spindles, a coupled model of thermal-flow-structure was established. Through experiment and simulation, the thermal characteristics of spiral cooling motorized spindle are studied, and the U-shaped cooled motorized spindle is designed and optimized. The simulation results show that when the diameter of the cooling channel is 7 mm, the temperature of the spiral cooling system is lower than that of the U-shaped cooling system, but the radial thermal deformation is greater than that of the U-shaped cooling system. As the increase of the channel diameter of U-shaped cooling system, the temperature and radial thermal deformation decrease. When the diameter is 10 mm, the temperature and radial thermal deformation are lower than the spiral cooling system. And as the flow rate increases, the temperature and radial thermal deformation gradually decrease, which provides a basis for a reasonable choice of water flow rate. The maximum error between experiment and simulation is 2°C, and the error is small, which verifies the accuracy and lays the foundation for future research.

Development and Validation of a Three-Dimensional Multiphase Flow CFD Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Experimental Data ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
High Speed ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Present Contribution ◽  
Two Phase

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach including cavitation and air entrainment for high-speed turbo-machinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty type gas turbine journal bearings.

Theoretical analysis and experimental study on thermal stability of high-speed motorized spindle

2017 ◽  
Vol 69 (6) ◽  
pp. 1049-1065 ◽  
Author(s):  
Zhe Liu ◽  
Wei Chen ◽  
Desheng Li ◽  
Wenjing Zhang
Keyword(s):  
Thermal Stability ◽  
Experimental Study ◽  
Theoretical Analysis ◽  
High Speed ◽  
Thermal Deformation ◽  
Motorized Spindle ◽  
Content Type ◽  
Front End ◽  
Temperature Distributions ◽  
Thermal Stability Of

Purpose In high-speed processing, the influence on the machining accuracy of a machine tool is greatly caused by the thermal deformation of the motorized spindle; a further study on the thermal characteristics of the spindle is given in this paper. This study aims to reduce the thermal error and improve the performance of the machine tool by discussing the relationships between the temperature distributions and rotating accuracy caused by the thermal deformations of the spindle. Design/methodology/approach The paper opted for a method combining the theoretical analysis and the experimental study to study the thermal stability of the high-speed motorized spindle. First of all, a finite element model of the spindle was built with ANSYS, whereby temperature distributions and the thermal deformations were successively obtained at different speeds. And then, both the temperature field and the rotating accuracy of the motorized spindle were measured simultaneously by the thermal stability experiment. Finally, the experimental and theoretical results were compared and validated. Findings The thermal stability of the motorized spindle was studied in this paper, and some findings from the study were as follows: the spindle’s rotating accuracy maintained good in X direction but bad in Y and Z directions in terms of the deformations; the higher front-end temperature of the spindle which can significantly affect the rotating accuracy is needed to be controlled mainly; the recovery speed of the spindle deformation lagged behind the temperature’s fallback speed; the vibration graph about radial rotating sensitivity synthesized by X1 and X2 presented a trifoliate shape. Originality/value Based on a built test-bed which can synchronously measure the motorized spindle’s temperature distribution and rotating accuracy with five-point method, the coupling effects of the thermal deformation and temperature are embodied, and not only the vibration graph but also the thermal tilt angles can be gained. Therefore, considering the influence of the thermal deformation on the heat generated by the bearings, the paper fulfilled a study by which it was obtained that the front-end temperature of the spindle, which was higher and could significantly affect the rotating accuracy, needed to be controlled mainly.

scholarly journals Mathematical Model and Analysis of the Water-Lubricated Hydrostatic Journal Bearings considering the Translational and Tilting Motions

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Hui-Hui Feng ◽  
Chun-Dong Xu ◽  
Jie Wan
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Journal Bearings ◽  
Linear Perturbation ◽  
Eccentricity Ratio ◽  
Dynamic Coefficients ◽  
Pressure Fields ◽  
Dynamic Performances ◽  
Rotary Speed

The water-lubricated bearings have been paid attention for their advantages to reduce the power loss and temperature rise and increase load capacity at high speed. To fully study the complete dynamic coefficients of two water-lubricated, hydrostatic journal bearings used to support a rigid rotor, a four-degree-of-freedom model considering the translational and tilting motion is presented. The effects of tilting ratio, rotary speed, and eccentricity ratio on the static and dynamic performances of the bearings are investigated. The bulk turbulent Reynolds equation is adopted. The finite difference method and a linear perturbation method are used to calculate the zeroth- and first-order pressure fields to obtain the static and dynamic coefficients. The results suggest that when the tilting ratio is smaller than 0.4 or the eccentricity ratio is smaller than 0.1, the static and dynamic characteristics are relatively insensitive to the tilting and eccentricity ratios; however, for larger tilting or eccentricity ratios, the tilting and eccentric effects should be fully considered. Meanwhile, the rotary speed significantly affects the performance of the hydrostatic, water-lubricated bearings.

Thermal Behavior and Friction in Journal Bearings

1970 ◽  
Vol 92 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Al. Nica
Keyword(s):  
Experimental Data ◽  
Thermal Behavior ◽  
Heat Dissipation ◽  
Journal Bearings ◽  
Friction Torque ◽  
Operating Characteristics ◽  
Lubricant Flow ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement

This paper deals with friction and the field of temperature in the lubricant film of journal bearings. Theoretical results regarding the thermal behavior are checked with experimental data and good agreement is found. Emphasis is put on the variation of temperature and lubricant flow with the operating characteristics of the bearing and it is seen that theoretical predictions for minima of friction torque are backed by temperature measurements. Further on, the friction torque and the mechanism of heat dissipation in bearings are dealt with, in order to verify the assumptions used in the calculation schemes. The means of efficiently cooling the bearing are also discussed, as well as the part played by the divergent zone in this process.

Stabilization Method for Small-Bore Journal Bearings Utilizing Starved Lubrication

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Hiromu Hashimoto ◽  
Masayuki Ochiai
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Control Mechanism ◽  
Journal Bearings ◽  
Test Rig ◽  
Stabilization Method ◽  
Speed Test ◽  
Nonlinear Motion ◽  
Starved Lubrication ◽  
Theoretical Results

This paper describes the stabilization method for small-bore circular journal bearings using starved lubrication. First, we describe the experimental examination to confirm the effect of supply oil conditions on stability of circular journal bearing by using a high-speed test rig. Then, the theoretical model considering the effect of amount of supply oil is discussed. Journal center trajectories are calculated by nonlinear motion analysis under various conditions. The theoretical results agree well with the experimental ones for three types of supply oil conditions and the mechanism of the stabilization by using the starved lubrication for small-bore journal bearings is clarified. Moreover, we suggest a supply oil control mechanism to stabilize the journal bearing using starved lubrication. Finally, the effectiveness of the proposed control mechanism on stability for high-speed small-bore journal bearings is verified experimentally.

Experimental and Numerical Rotordynamic Analysis of a 1500 KW Turbocharger

2020 ◽  
Author(s):  
Behzad Zamanian Yazdi ◽  
Dung L. Tran ◽  
Chinmay Deshpande
Keyword(s):  
Experimental Data ◽  
Analytical Model ◽  
High Speed ◽  
Journal Bearings ◽  
Acid Gas ◽  
Test Loop ◽  
Gas Removal ◽  
Rotor Bearing ◽  
Simulation Results ◽  
Bearing System

Abstract Hydraulic turbochargers are used in sea water reverse osmosis or acid gas removal cycles to recover wasted pressure energy, decrease operating cost, and increase the overall process efficiency. This paper presents rotordynamic analysis of a large hydraulic turbocharger developed for the acid gas removal process (1500 KW output power, shaft diameter of 101 mm, and operating speed of 8,000 rpm). The hydraulic turbocharger has significant advantages when compared to a reverse running pump such as high speed, compact hydraulics, seal-less design and process lubricated bearings. Utilizing a hydraulic turbocharger in acid gas removal cycles results in a much smaller footprint and no external lubrication oil skid and support system for mechanical seals. The turbocharger rotor consists of a hydraulic turbine runner directly coupled to a pump impeller in a back-to-back arrangement. The shaft is supported in the middle by a set of rigid-walled process-lubricated journal bearings resulting in an overhung configuration (bearing span = 180 mm, rotor mass = 50 kg). For a large high-speed rotor-bearing system, the bearing load-carrying capacity and rotordynamic stability are crucial to ensure a stable performance and to avoid catastrophic failure. In the presented study, rotordynamic performance of a rotor-bearing system is evaluated analytically and experimentally. An analytical model is developed to simulate the rotordynamic performance of a shaft supported by a set of journal bearings. The analytical model simulates the rotor’s orbit in the time domain by solving the rotor’s equation of motion, and solving the transient Reynold equation for each bearing simultaneously. In addition, the model considers the effect of turbulence. An in-house test loop is developed and used to evaluate the turbocharger’s hydraulic and mechanical performance. The test loop runs on a LabView-based control system. The rotor vibration is measured by a set of eddy-current probes, oriented perpendicular to each other. The simulation results from the analytical model are compared against measured experimental data. Comparison of the simulated waterfall and bode plots with experimental data shows that the simulation results agree with the measured data for the frequency and amplitude of vibration. Moreover, the effect of turbulence on the rotordynamic performance of the hydraulic turbocharger is investigated, and it is shown that the turbulence significantly changes the rotordynamic behavior of the system.

Effects of High-Operating Speeds on Tilting Pad Thrust Bearing Performance

1976 ◽  
Vol 98 (1) ◽  
pp. 73-79 ◽  
Author(s):  
J. W. Capitao ◽  
R. S. Gregory ◽  
R. P. Whitford
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Power Loss ◽  
High Speed ◽  
Thrust Bearing ◽  
Full Scale ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
Speed Performance ◽  
Bearing Loads

A comparison of the high-speed performance characteristics of tilting-pad, self-equalizing type thrust bearings through two independent full-scale programs is reported. This paper presents experimental data on centrally pivoted, 6-pad, 267-mm (10 1/2-in.) and 304-mm (12-in.) O.D. bearings operating at shaft speeds up to 14000 rpm and bearing loads ranging up to 2.76 MPa (400 psi). Data presented demonstrate the effects of speed and loading on bearing power loss and metal temperatures. Included is a discussion of optimum oil supply flow rate based upon considerations of bearing pad temperatures and power loss values.

A Study of the Thermohydrodynamic Performance of a Plain Journal Bearing Comparison Between Theory and Experiments

1983 ◽  
Vol 105 (3) ◽  
pp. 422-428 ◽  
Author(s):  
J. Ferron ◽  
J. Frene ◽  
R. Boncompain
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Temperature Distribution ◽  
Journal Bearing ◽  
Experimental Program ◽  
Plain Bearing ◽  
Eccentricity Ratio ◽  
Theoretical Results ◽  
Theory And Experiments ◽  
Original Device

Both theoretical and experimental thermohydrodynamic problem of a finite length journal bearing is studied. The analysis takes into acount heat transfer between the film and both the shaft and the bush. Cavitation and lubricant recirculation are also taken into account. The experimental program is conducted on an original device to study the performance of a plain bearing. The pressure and the temperature distribution on bearing wall are measured along with the eccentricity ratio and the flows rate for different speeds and loads. The effect on the eccentricity ratio of differential dilatation is underlined. Agreement between theoretical results and experimental data is satisfactory.

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