Impact of velocity slippage on the behaviour of PVP lubricated multirecessed hybrid journal bearing

In oil film journal bearings, the solid-liquid interfaces are susceptible to velocity slippage due to several factors such as low oil viscosity near solid surface, molecular slippage or wettability of coating material. Moreover, presence of long chain polymer additives in the base oil induces polarity effect in presence of couple-stresses and at high pressure conditions, these additized lubricants exhibit piezo-viscosity. This article presents a novel investigation to evaluate the impact of velocity slippage on the behaviour of multirecessed hybrid journal bearing (MHJB) system functioning with PVP lubricant. To govern the flow behaviour of PVP lubricant in MHJB, the novel forms of Reynolds equations are obtained for various velocity slippage conditions. These governing equations are numerically solved using FEM to evaluate nodal values of oil film pressure and characteristic parameters of bearing system. The simulated results reveal that the velocity slippage causes a substantial degradation in the performance parameters, viz., <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mover> <mml:mrow> <mml:mspace width=".1em"/> <mml:mi>p</mml:mi> </mml:mrow> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi>m</mml:mi> <mml:mi>a</mml:mi> <mml:mi>x</mml:mi> </mml:mrow> </mml:msub> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mover> <mml:mi>h</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi>m</mml:mi> <mml:mi>i</mml:mi> <mml:mi>n</mml:mi> </mml:mrow> </mml:msub> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mover> <mml:mi>Q</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mover> <mml:mi>S</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi>i</mml:mi> <mml:mi>j</mml:mi> </mml:mrow> </mml:msub> </mml:math> , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mover> <mml:mi>C</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> <mml:mrow> <mml:mi>i</mml:mi> <mml:mi>j</mml:mi> </mml:mrow> </mml:msub> </mml:math> . The application of PVP lubricant instead of Newtonian lubricant may partially recuperate this degradation in the bearing's characteristics.