Essential analysis and quantitative evaluation on mechanical-energy loss of fluid momentum wheel

Abstract

The Fluid Momentum Wheel (FMW), an innovative anti-roll device, requires accurate evaluations of mechanical-energy loss within its flow field due to the direct impact on its anti-roll capability. In this paper, the characteristics of the internal flow field and the essential reasons for the mechanical-energy loss of FMW were analyzed through numerical simulations. The results show that the mechanical-energy loss of FMW can be unified with the form of the traditional empirical formula. However, a substantial relative difference of up to 30.59% was observed between the empirical formula and numerical solutions, indicating limitations of traditional empirical formula in predicting the mechanical-energy loss of the FMW. Secondary flow in the cross-section and the asymmetrical distribution of fluid velocity in the main flow direction were identified as essential factors limiting the traditional formula's accuracy. Next, three dimensionless parameters of Reynolds number, curvature ratio, and center-distance ratio are presented to evaluate the mechanical-energy loss according to the fluid characteristics of FMW. Orthogonal experiments are conducted for parametric sensitivity analysis to study the interactive effects and significance of these parameters on the mechanical-energy loss. Finally, the characteristics of the loss coefficients with the variation of parameters are explained by the results of the flow velocity and turbulent kinetic energy in the cross-section. A linear relationship between the loss coefficients and the logarithm of the Reynolds number at various curvature ratios. Based on the above analysis, a new quantitative evaluation formula for the mechanical-energy loss of FMW is proposed and validated, which can support improved anti-roll control of FMW.