A generalized thermoelastic instability analysis

Jang, Jinho; Khonsari, M. M.

doi:10.1098/rspa.2002.1030

Cited by 36 publications

(11 citation statements)

References 23 publications

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“…Assuming that all the perturbed heat generation goes into the conductor, equations (5) and (9) can be properly used in equation (12) and the following relation arises:…”

Section: The Heat Balance Under Perturbationmentioning

confidence: 99%

On the thermoelastic instability of a thin-film-lubricated sliding contact: A closed-form solution

Peng

Khonsari

Pascovici

2003

Proceedings of the Institution of Mechanical Engineers, Part J:

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Thermoelastic instability (TEI) in a mechanical component manifests itself in the form of macroscopic hot spots. To gain insight into the mechanism of hot spotting, an engineering TEI model for two solid surfaces separated by a viscous liquid ®lm in relative sliding motion is developed. The model lends itself to a useful analytical expression for determining the threshold of instability with provision for the effect of the migration speed. NOTATION a wave number associated with perturbation in the y direction (m ¡1 ) A amplitude of the perturbed surface temperature (K) A s wetted surface area of the conductor (m 2 ) c migration speed in the local coordinate x direction (m/s) d penetration depth (m) E Young's modulus (N/m 2 ) h total ®lm thickness (m) h 0 perturbation (m) h 0 nominal ®lm thickness (m) k conductivity (W/m K) L radial width of the mechanical seal (m) m width factor of the seal lip p hydrodynamic pressure (Pa) q total heat¯ux (W/m 2 ) q 0 perturbed heat¯ux (W/m 2 ) q 0 nominal heat¯ux (W/m 2 ) Q heat generated (W) t time (s) T 0 perturbed temperature ®eld (K) T 0 s perturbed surface temperature (K) u¯ow velocity in the x direction (m/s) U operating speed (m/s) U cr critical operating speed (m/s) V volume of¯uid (m 3 ) w¯ow velocity in the z direction (m/s) x local coordinate in the moving direction y local coordinate inward normal to the conductor surface z local coordinate into the paper a coef®cient of expansion (K ¡1 ) b stability parameter (s ¡1 ) _ g g viscous strain rate (s ¡1 ) d 0 total surface deformation (m) d 0 e elastic surface deformation (m) d 0 th perturbed thermal expansion (m) k thermal diffusivity (m 2 /s) m¯uid viscosity (Pa s) O wave number associated with perturbation in the x direction (m ¡1 ) t shear stress (N/m 2 ) x spatial growth parameter of the perturbed temperature (m ¡1 )

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“…Assuming that all the perturbed heat generation goes into the conductor, equations (5) and (9) can be properly used in equation (12) and the following relation arises:…”

Section: The Heat Balance Under Perturbationmentioning

confidence: 99%

On the thermoelastic instability of a thin-film-lubricated sliding contact: A closed-form solution

Peng

Khonsari

Pascovici

2003

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…For example, a high rubbing face temperature tends to lower the lubricant viscosity and results in a lower load-carrying capacity. The lack of proper thermal management in mechanical face seals can result in different types of surface damage such as heat checking and cracking or hot spotting due to thermoelastic instability [9,10]. In addition, high face temperature may evaporate the lubricant in between the seal ring faces and cause face distortion [11].…”

Section: Introductionmentioning

confidence: 99%

Improving Bearings Thermal and Tribological Performance with Built-In Heat Pipe

Xiao

Khonsari

2015

Tribol Lett

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A recent experimental investigation revealed that a mechanical face seal with built-in heat pipe can significantly reduce the interfacial contact temperature (Xiao and Khonsari in J Eng Tribol 228(5):498-510, 2014). Further experimental tests are set up to investigate the effect of thermal and lubrication characteristics in a thrustbearing configuration with built-in heat pipes either in the stationary or in the rotating component. During the tests, the rotating disk slides against the stationary disk in an oil reservoir filled with SAE 10 engine oil. Both disks are made of heat-treated stainless steel 17-4 PH with the same hardness. Rubbing face temperature and surface friction coefficient are measured from both the heat pipe and conventional disk pair and the conventional disk pair. The test results show that both the heat pipe stationary and rotating disks are capable of reducing the temperature and friction coefficient.

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“…Different types of damage are likely to occur if this balance is disrupted. One class of failure, for example, is a localized surface damage known as thermoelastic instability (TEI) that occurs due to unstable thermal growth that manifests itself in the form of macroscopic hot spots or dark patches on the surface that can be viewed with the naked eye [1][2][3][4][5][6]. The occurrence of TEI has been widely reported in automatic brakes [4,7,8], clutches [5,[9][10][11] and mechanical seals [12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%