Bidirectional axial-flow and tubular pump systems play a critical role in modern hydraulic engineering applications, particularly in tidal energy conversion, flood control, irrigation drainage, and reversible pumping stations. Unlike conventional unidirectional pumps, these systems must maintain acceptable hydraulic performance, stability, and structural reliability under both forward and reverse operating modes. This dual-function requirement introduces complex challenges related to blade design, internal flow structure, pressure pulsation, vibration, and efficiency degradation. The present research article offers an extensive theoretical and analytical investigation into the optimization mechanisms, internal flow behaviors, and unsteady pressure characteristics of bidirectional shaft tubular pumps and reversible axial-flow pump devices. Drawing strictly and exclusively from the provided body of peer-reviewed literature, this study synthesizes prior experimental, numerical, and theoretical findings to construct a unified and deeply elaborated understanding of reversible pump behavior. Special attention is given to the influence of blade airfoil geometry, trailing-edge modification, rotor–stator interaction, tip clearance effects, flow separation phenomena, and pressure pulsation mechanisms under variable load conditions. The methodology of this work is grounded in qualitative synthesis and comparative theoretical analysis rather than new experimental or numerical data, allowing for a comprehensive reinterpretation of existing results. The findings highlight that performance asymmetry between forward and reverse modes is fundamentally linked to blade camber distribution, flow incidence mismatch, and wake–blade interaction dynamics. Furthermore, unsteady pressure pulsations are shown to be inseparable from geometric optimization decisions, particularly at partial load and off-design conditions. The discussion critically examines current limitations in bidirectional pump design practices and outlines future research pathways focused on integrated aero-hydrodynamic optimization, vibration mitigation, and long-term operational reliability. This article aims to serve as a definitive theoretical reference for researchers and engineers working on reversible pump technologies.
