Measurement and Prediction of the Journal Circumferential Temperature Distribution for the Rotordynamic Morton Effect

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Xiaomeng Tong ◽  
Alan Palazzolo
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Hot Spot ◽  
Angular Position ◽  
Three Dimensional ◽  
3D Fem ◽  
Transient Model ◽  
Morton Effect ◽  
Tilting Pad Journal Bearing ◽  
Prediction Approach

The journal is the part of a shaft that is inside a fluid film bearing and is usually assumed to be circumferentially isothermal. Recent work has shown that under certain vibration conditions, a significant temperature difference (ΔT) can develop around the journal circumference. The ΔT may cause the shaft to bend leading to a synchronous vibration instability problem, termed the “Morton effect” (ME). A test rig was developed to verify the asymmetric journal temperature of the ME and its prediction using a five-pad tilting pad journal bearing (TPJB) operating with an eccentric shaft to replicate a circular vibration orbit. The bearing is tested at various conditions including: supply oil temperature at 28 °C and 41 °C, bearing operating eccentricities of zero and 32%Cb, and rotor speed up to 5500 rpm. The journal temperature distribution is recorded with 20 sensors located around the journal circumference, and the measurements provide a benchmark for predictions from a time transient model with the three-dimensional (3D) fluid and solid finite element method (FEM), and with a simplified ME prediction approach using only steady-state results. The test results follow the predictions exhibiting a sinusoidal-like temperature profile around the circumference with an angular lag of the hot spot location behind the high spot location (angular position on the rotor that arrives at the minimum film thickness condition each rotation) by a speed-dependent angle. Increasing the supply oil temperature reduced the journal ΔT, while increasing the bearing operating eccentricity increased the journal ΔT. The agreement between the test and predicted results is significantly better for the 3D FEM transient model than for the steady-state-based model in terms of journal ΔT and hot spot position. An improved version of the latter approach is proposed and yields significantly better correlation with the test measurements.

Direct observation of three-dimensional transient temperature distribution in SiC Schottky barrier diode under operation by optical-interference contactless thermometry (OICT) imaging

2022 ◽  
Author(s):  
Keiya Fujimoto ◽  
Hiroaki Hanafusa ◽  
Takuma Sato ◽  
Seiichiro HIGASHI
Keyword(s):  
Temperature Distribution ◽  
Schottky Barrier ◽  
Hot Spot ◽  
Local Heating ◽  
Three Dimensional ◽  
Schottky Barrier Diode ◽  
Transient Temperature ◽  
Optical Interference ◽  
Transient Temperature Distribution ◽  
Heating And Cooling

Abstract We have developed optical-interference contactless thermometry (OICT) imaging technique to visualize three-dimensional transient temperature distribution in 4H-SiC Schottky barrier diode (SBD) under operation. When a 1 ms forward pulse bias was applied, clear variation of optical interference fringes induced by self-heating and cooling were observed. Thermal diffusion and optical analysis revealed three-dimensional temperature distribution with high spatial (≤ 10 μm) and temporal (≤ 100 μs) resolutions. A hot spot that signals breakdown of the SBD was successfully captured as an anormal interference, which indicated a local heating to a temperature as high as 805 K at the time of failure.

Squeeze Film Damper Suppression of Thermal Bow-Morton Effect Instability

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Dongil Shin ◽  
Alan B. Palazzolo ◽  
Xiaomeng Tong
Keyword(s):  
Three Dimensional ◽  
Squeeze Film ◽  
Viscous Heating ◽  
Fluid Inertia ◽  
Euler Beam ◽  
Nonlinear Simulation ◽  
Squeeze Film Damper ◽  
Morton Effect ◽  
Tilting Pad Journal Bearing ◽  
Rotor Model

Abstract The Morton effect (ME) is a synchronous vibration problem in turbomachinery caused by the nonuniform viscous heating around the journal circumference, and its resultant thermal bow (TB) and ensuing synchronous vibration. This paper treats the unconventional application of the SFD for the mitigation of ME-induced vibration. Installing a properly designed squeeze film damper (SFD) may change the rotor's critical speed location, damping, and deflection shape, and thereby suppress the vibration caused by the ME. The effectiveness of the SFD on suppressing the ME is tested via linear and nonlinear simulation studies employing a three-dimensional (3D) thermohydrodynamic (THD) tilting pad journal bearing (TJPB), and a flexible, Euler beam rotor model. The example rotor model is for a compressor that experimentally exhibited an unacceptable vibration level along with significant journal differential heating near 8000 rpm. The SFD model includes fluid inertia and is installed on the nondrive end bearing location where the asymmetric viscous heating of the journal is highest. The influence of SFD cage stiffness is evaluated.

Experimental Measurements of Temperature Distribution in Three Dimensional Stacked Package

2007 ◽  
Author(s):  
Anand Desai ◽  
James Geer ◽  
Bahgat Sammakia
Keyword(s):  
Experimental Study ◽  
Heat Conduction ◽  
Steady State ◽  
Temperature Distribution ◽  
Numerical Model ◽  
Analytical Solution ◽  
Three Dimensional ◽  
Power Input ◽  
Experimental Measurements ◽  
Steady State Heat

This paper presents the results of an experimental study of steady state heat conduction in a three dimensional stack package. The temperatures are measured at different interfaces within the stacked package. Delphi devices are used in the experiment which enables controlled power input and surface temperature of the devices. The experiment is carried out for three different boundary conditions on the package. The power input in varied to study its effects. A numerical model is created to compare to the experimental results. The results are also compared with the analytical solution presented in Desai et al [5] and Geer et al [6]. The results indicate that the experimental, numerical and analytical solutions follow the same trend. The agreement between the experimental and numerical results improves when the lateral losses are taken into account.

A Full Numerical Solution for the Thermoelastohydrodynamic Problem in Elliptical Contacts

1984 ◽  
Vol 106 (2) ◽  
pp. 246-254 ◽  
Author(s):  
Dong Zhu ◽  
Shi-zhu Wen
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Numerical Solution ◽  
Pressure Distribution ◽  
Three Dimensional ◽  
Thermal Action ◽  
Film Pressure ◽  
Rolling Velocity ◽  
Friction Factors

In this paper a full numerical solution for the thermoelastohydrodynamic problem in elliptical contacts is presented, and the method of computation is also described. The film pressure, thickness, and film shape, the three dimensional temperature distribution within both the film and the bounding solids, as well as the coefficients of the sliding and rolling frictions have all been determined for different rolling velocities and slide-roll ratios. The results obtained indicate the film temperature increases as the rolling velocity or slide-roll ratio increases. The effects of thermal action on the pressure distribution, the film shape and thickness, and the friction factors are also given. The problem studied in this paper is steady-state, the lubricant is assumed to be Newtonian.

scholarly journals Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 110
Author(s):  
Dmitry Bisikalo ◽  
Andrey Sobolev ◽  
Andrey Zhilkin
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Temperature Distribution ◽  
Hot Spots ◽  
Transfer Rate ◽  
Hot Spot ◽  
Mass Transfer Rate ◽  
Three Dimensional ◽  
Jet Trajectory ◽  
Dominant Influence

In this paper, the characteristics of hot spots on an accretor surface are investigated for two types of polars: the eclipsing synchronous polar V808 Aur and the non-eclipsing asynchronous polar CD Ind in configuration of an offset and non-offset magnetic dipole. The drift of hot spots is analyzed based on the results of numerical calculations and maps of the temperature distribution over the accretor surface. It is shown that a noticeable displacement of the spots is determined by the ratio of ballistic and magnetic parts of the jet trajectory. In the synchronous polar, the dominant influence on the drift of hot spots is exerted by variations in the mass transfer rate, which entail a change in the ballistic part of the trajectory. It was found that when the mass transfer rate changes within the range of 10−10M⊙/year to 10−7M⊙/year, the displacement of the hot spot in latitude and longitude can reach 30∘. In the asynchronous polar, a change in the position of hot spots is mainly defined by the properties of the white dwarf magnetosphere, and the displacement of hot spots in latitude and longitude can reach 20∘.

scholarly journals Analytical study of the temperature distribution in solids subjected to nonuniform moving heat sources

2013 ◽  
Vol 17 (3) ◽  
pp. 687-694 ◽  
Author(s):  
Mohamed Hamraoui ◽  
Mounir Chbiki ◽  
Najib Laraqi ◽  
Luis Roseiro
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Power Dissipation ◽  
Relative Velocity ◽  
Analytical Study ◽  
Three Dimensional ◽  
Total Power ◽  
Heat Sources ◽  
Reference Case ◽  
Made In

We propose in this paper an analytical study of the temperature distribution in a solid subjected to moving heat sources. The power dissipated by the heat sources is considered nonuniform. The study was made in steady state. The model is three-dimensional. It is valid regardless of the relative velocity of the source. We have considered three cases of semi-elliptic distribution of the power with: (i) the maximum at the center of the source, (ii) the maximum at the inlet of the source, (iii) the maximum at the output of the source. These configurations simulate the conformity imperfection of contact due to wear and / or the non-uniformity of contact pressure in frictional devices. We compare the temperature change for these different scenarios and for different relative velocities, considering the same total power dissipation. The reference case is that of a uniform source dissipating the same power.

Analysis of the Effect of Heating Control Conditions on Temperature Distribution in a Wafer During Rapid Thermal Processing With Lamp Heaters

2001 ◽  
Author(s):  
Shigeki Hirasawa ◽  
Tadashi Suzuki ◽  
Shigenao Maruyama ◽  
Yuhei Takeuchi
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Thermal Processing ◽  
Radiative Heat ◽  
Rapid Thermal Processing ◽  
Three Dimensional ◽  
Heating Process ◽  
Computation Technique ◽  
Shielding Ring ◽  
Optimum Heating

Abstract To unify temperature distribution in a wafer during rapid thermal processing, we calculated the effect of the heating control conditions on temperature distributions in the wafer during heat-up and at steady state by using a program for analyzing three-dimensional radiative heat transfer. We calculated optimum monitoring positions on the wafer in order to minimize the temperature distribution in the wafer. The effects of rotating the wafer, the spacing between the wafer and the shielding ring, the number of monitoring positions, and the initial non-uniform temperature distribution were also calculated. The minimum steady temperature distribution in the wafer at the optimum condition was calculated as ±0.1 K during 100 K/s heat-up and ±0.02 K at 1273 K steady state. We also developed a rapid parallel-computation technique to find the optimum heating control conditions for the whole heating process.

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