Stack-Up Forces for Normal and Abnormal Operating Conditions in a Railroad Roller Bearing Assembly

1998 ◽  
Vol 120 (4) ◽  
pp. 707-713
Author(s):  
H. Wang ◽  
T. F. Conry ◽  
C. Cusano

Stack-up force distributions are obtained for normal and abnormal operating conditions in a class F (6 1/2 × 12) railroad tapered roller bearing-axle assembly for various friction coefficients, press-fits and cap screw preloads. Three conditions that affect the stack-up force distribution are considered: a steady-state normal-operating temperature distribution, a steady-state temperature distribution resulting from a stuck brake or a jammed outboard roller, and a transient temperature distribution due to multiple jammed outboard rollers. The steady-state normal or abnormal operating temperature have insignificant effects for nominal values of interference, friction and cap screw preload. However, the effect of the transient temperature due to multiple jammed outboard rollers on the stack-up system is detrimental due to localized high temperature gradients near the outboard cone area and a distortion of the original surface geometry of the cone.

2000 ◽  
Author(s):  
Patrick Kwon

Abstract A new technique is developed to estimate the average steady state chip-tool interface temperature during turning. An infrared (IR) video camera attached on the carriage of the lathe measures the transient cooling behavior on the rake surface of an insert after the feed motion is halted. This allows the zero heat flux boundary condition, where the transient Laplace heat conduction problem can be solved numerically to obtain the temporal and spatial temperature distribution. With the experimentally determined transient temperature distribution, the 1-D ellipsoidal model is used to estimate the average steady-state chip-tool interface temperature during machining. The results on turning Gray Cast Iron (GCI) and AISI 1045 steels with various coated and uncoated carbide inserts are presented.


1987 ◽  
Vol 109 (3) ◽  
pp. 496-501 ◽  
Author(s):  
M. Rashid ◽  
A. Seireg

The computer-based model described in Part I is utilized in this paper to develop dimensionless relationships for lubricated unlayered contacts and dry layered contacts. Because of the recent interest in tribological surface coating these relationships can be used to provide parametric evaluations of heat partition and temperature rise in the contacts under different coating parameters and operating conditions.


2014 ◽  
Vol 35 (2) ◽  
pp. 117-133 ◽  
Author(s):  
Dawid Taler ◽  
Jan Taler

Abstract Various methods for steady-state and transient analysis of temperature distribution and efficiency of continuous-plate fins are presented. For a constant heat transfer coefficient over the fin surface, the plate fin can be divided into imaginary rectangular or hexangular fins. At first approximate methods for determining the steady-state fin efficiency like the method of equivalent circular fin and the sector method are discussed. When the fin geometry is complex, thus transient temperature distribution and fin efficiency can be determined using numerical methods. A numerical method for transient analysis of fins with complex geometry is developed. Transient temperature distributions in continuous fins attached to oval tubes is computed using the finite volume - finite element methods. The developed method can be used in the transient analysis of compact heat exchangers to calculate correctly the heat flow rate transferred from the finned tubes to the fluid.


Author(s):  
Keiya Fujimoto ◽  
Hiroaki Hanafusa ◽  
Takuma Sato ◽  
Seiichiro HIGASHI

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.


2021 ◽  
Vol 141 (11) ◽  
pp. 712-717
Author(s):  
Akira Daibo ◽  
Yoshimitsu Niwa ◽  
Naoki Asari ◽  
Wataru Sakaguchi ◽  
Yo Sasaki ◽  
...  

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2935 ◽  
Author(s):  
Sayantan Ganguly

An exact integral solution for transient temperature distribution, due to injection-production, in a heterogeneous porous confined geothermal reservoir, is presented in this paper. The heat transport processes taken into account are advection, longitudinal conduction and conduction to the confining rock layers due to the vertical temperature gradient. A quasi 2D heat transport equation in a semi-infinite porous media is solved using the Laplace transform. The internal heterogeneity of the geothermal reservoir is expressed by spatial variation of the flow velocity and the effective thermal conductivity of the medium. The model results predict the transient temperature distribution and thermal-front movement in a geothermal reservoir and the confining rocks. Another transient solution is also derived, assuming that longitudinal conduction in the geothermal aquifer is negligible. Steady-state solutions are presented, which determine the maximum penetration of the cold water thermal front into the geothermal aquifer.


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