Transient tribo-dynamic analysis of crosshead slipper in low-speed marine diesel engines during engine startup

Abstract

A crosshead slipper-guide system, which bears a significant thrust force, is an essential friction pair in low-speed marine diesel engines. Owing to the low moving speed of the crosshead slipper during engine startup, it is difficult to form good hydrodynamic lubrication between the crosshead slipper and guide. Therefore, a detailed analysis of the crosshead slipper during engine startup is needed. In this study, a new transient tribo-dynamic model for a crosshead slipper during the engine startup process is presented. The model consists of a mixed lubrication model of the crosshead slipper-guide and dynamic models of the piston assembly, crosshead assembly, connecting rod, and crankshaft. The tribo-dynamic performances of the crosshead slipper during startup and under the rated conditions were simulated and compared. The results show that the tribo-dynamics of the crosshead slipper during the startup process are significantly different from those under the rated conditions. Some measures beneficial for the low friction of a crosshead slipper-guide under the rated conditions may significantly increase the friction loss of the crosshead slipper-guide system during the startup process.

Numerical study of piston group and crosshead guide system dynamics for a two‐stroke marine engine

“…The equations of motion for the coupled system, Equation (33), and all the expressions for the forces and moments on the right‐hand side of Equation (33), constitute an initial value problem for a pair of nonlinear second order differential equations in $$$ {\mathrm{e}}_{\mathrm{t}} $$$, $$$ {\mathrm{e}}_{\mathrm{b}} $$$, $$$ {\mathrm{e}}_{\mathrm{tp}} $$$, and $$$ {\mathrm{e}}_{\mathrm{bp}} $$$. Similar initial value problems have previously been solved with Runge Kutta method, 23 Adams–Bashforth–Moulton (multi‐step) methods, Newton Raphson method, 3‐5 Quasi Newton methods (Broyden), 7,29 and modified extended backward differentiation method 20‐22,30 . In this article, ode15s is used to solve the stiff nonlinear initial value problem.…”

“…Similar initial value problems have previously been solved with Runge Kutta method, 23 Adams-Bashforth-Moulton (multi-step) methods, Newton Raphson method, [3][4][5] Quasi Newton methods (Broyden), 7,29 and modified extended backward differentiation method. [20][21][22]30 In this article, ode15s is used to solve the stiff nonlinear initial value problem. At each time step, the Reynold's equation is solved for the piston skirt-liner and crosshead guide systems to obtain the oil film pressure which is integrated over the lubricated surface to obtain the pressure forces, corresponding moments, and friction characteristics of contiguous surfaces.…”

“…Based on the coupled tribodynamic model, it is reported that the tribodynamic behavior is sensitive to connecting rod inertia. Another recent contribution investigated the tribodynamic behavior of the crosshead guide shoes during engine start‐up 22 …”

“…Another recent contribution investigated the tribodynamic behavior of the crosshead guide shoes during engine start-up. 22 In the current research, nonlinear second order tribodynamic models are developed and solved for secondary tribodynamic characteristics; displacements, velocities and friction characteristics, and related to occurrence and magnitude of structural impacts on the engine. The impacts considered are as a result of secondary motions of the coupled system consisting of piston group and crosshead guide system.…”

Experimental study on the interface topography evolution and vibration monitoring in thrust ball bearings induced by particulate contamination

“…Gabelli et al (2008) evaluated the life of rolling bearings by calculating the rolling EHL contact stress. More recently, some scholars pay more attention to the coupling behavior of tribology and dynamics of bearings (Kuang et al, 2020;Li et al, 2020;Liu et al, 2021;Meng et al, 2021).…”