Non-Newtonian thermal analysis of an EHD contact lubricated with MIL-L-23699 oil

• Type: Article in International Scientific Journal
• Date: 2006

Authors

Armando Campos (Author) FEUP; Alexandre Sottomayor (Author) FEUP; Jorge Seabra (Author) FEUP

Journal

Title: Tribology International

Vol. 39

Pages: 1732-1744

ISSN: 0301-679X

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 13 Citations

Scientific classification

FOS: Engineering and technology > Mechanical engineering

Other information

Authenticus ID: P-004-FZR

DOI: 10.1016/j.triboint.2006.01.006

Abstract (EN): A thermal and non-Newtonian fluid model under elastohydrodynamic lubrication conditions is proposed, integrating some particularities, such as the separation between hydrodynamic and dissipative phenomena inside the contact. The concept of apparent viscosity is used to introduce the non-Newtonian behaviour of the lubricant and the thermal behaviour of the contact into the Reynolds equation, acting as a link element between the hydrodynamic and dissipative components of the EHD film, independently of the theological and thermal models considered. The apparent viscosity enables the application of the theological model better adapted to each lubricant, without appealing to special formulations of the EHD problem. The Newton-Raphson technique is used to obtain the lubricant film geometry and the pressure distribution inside the EHD contact. The shear stresses developed in the fluid film are evaluated assuming the non-linear Maxwell theological model. The surfaces and lubricant temperature distributions are determined using the simplified Houpert's method, applied to the inlet contact zone, and the thermal method proposed by Tevaarwerk is applied in the high pressure contact zone. The non-Newtonian thermal EHD model is applied to the analysis of a contact lubricated with MIL-L-23699 oil. Significant results are obtained for the centre and minimum film thickness, for the inlet shear heating and film thickness reduction factor (phi(T)), for the temperature rise of the lubricant and of the surfaces and for the friction coefficient inside the contact, considering wide ranges of the operating conditions (maximum Hertzian pressure, inlet oil temperature, rolling speed and slide-to-roll ratio). Finally, the numerical traction curves determined are compared with the corresponding experimental results, showing very good correlation.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 13