Thermodynamic effects of gasoline on suction pump performance in tropical fuel stations: A field-calibrated CFD and statistical model

Abstract

•Gasoline properties change between 15–40 °C under tropical field conditions.•Vapor pressure and viscosity are dominant drivers of suction pump instability.•Cavitation onset occurs beyond 30 °C, with NPSHa collapse and 59% efficiency.•Pump Performance Index (PPI) predicts cavitation and thermal efficiency loss.•PPI correlates strongly with NPSHa (r = 0.98) and vapor fraction (r = −0.97).•PPI enables real-time monitoring and predictive maintenance in tropical fuel stations. Suction pump fueling systems dominate Uganda’s downstream petroleum sector but face increasing reliability challenges under tropical thermal stress. In regions such as the Albertine Graben, where daytime temperatures often exceed 30 °C, gasoline properties shift significantly: density and viscosity decline, vapor pressure rises exponentially, and thermal conductivity remains nearly constant. These changes reduce Net Positive Suction Head Available (NPSHa), accelerate cavitation onset, and lower pump efficiency. To capture these effects, temperature-dependent property models were derived across the 15–40 °C range using 13 months of field-representative data from a commercial fueling station in Bulisa District. These models were implemented as user-defined functions within Computational Fluid Dynamics (CFD) simulations of a Gilbarco F210 suction pump, enabling evaluation of suction-side performance under tropical conditions. Regression and ANOVA analyses confirmed vapor pressure and viscosity as dominant drivers of instability, with density exerting secondary influence and conductivity a minor role. Based on these sensitivities, a dimensionless Pump Performance Index (PPI) was formulated, consolidating property trends into a predictive diagnostic metric. Validation against CFD outputs demonstrated strong correlations with NPSHa (r = 0.98), cavitation number (r = 0.97), efficiency (r = 0.96), and vapor fraction (r = −0.97), confirming predictive accuracy, and delineating three operational regimes: stable (≤25 °C), transition (∼30 °C), and critical (≥35 °C). The PPI provides a scalable tool for predictive maintenance, operational monitoring, and regulatory benchmarking, representing the first localized diagnostic framework for suction pump reliability in tropical fueling environments.