Optimizing journal bearing performance with bio‐lubricants using <scp>TOPSIS</scp> analysis

Abstract This study employs computational fluid dynamics (CFD) to investigate cavitation in a plain journal bearing, comparing mineral oil (ATF Dexron‐II) with bio‐lubricants (castor and palm oils). A steady, laminar flow, the Zwart–Gerber–Belamri model simulates cavitation using ANSYS 2023. Key metrics including pressure distribution, load‐carrying capacity, oil vapour volume fraction, and viscous power loss, are evaluated across varying eccentricity (0.4–0.6), length‐to‐diameter ratio (0.8–1.2), and speeds (1200–1800 RPM). Increasing these parameters results in an increase in all metrics, with varying effects depending on the lubricant and parameter. Eccentricity significantly impacts pressure and vaporization. Castor oil, with high viscosity and strong film formation, excels in load‐carrying capacity, ideal for high‐load applications. Palm oil, with lower viscosity and better oxidative stability, minimizes power loss, fitting low‐load scenarios. The TOPSIS model ranks castor oil highest in eight out of nine cases using equal weights. Sensitivity analysis shows castor oil leads for high load capacity or low vaporization, while palm oil excels for reduced power loss. These findings suggest that both bio‐lubricants are viable, eco‐friendly alternatives to mineral oil.