In the present study, the flow pulsation characteristics inherent to lobe pumps are rigorously examined. As a subclass of positive displacement pumps, lobe pumps inherently induce substantial periodic acceleration and deceleration of the working fluid within the control volume, resulting from the intermittent nature of fluid conveyance associated with their mechanical operation. This cyclic modulation in flow velocity gives rise to pronounced pulsations, which in turn generate both fluid-borne noise and mechanical vibrations due to fluctuating pressure fields acting upon the pump casing, as well as the inlet and outlet conduits. Moreover, these pulsations impose dynamic, oscillatory forces on the rotating shafts of the lobes, leading to persistent vibrations—an undesirable phenomenon that can precipitate premature mechanical degradation and contribute to structure-borne acoustic emissions.
The core focus of this investigation lies in assessing the influence of lobe geometry—recognized as the principal actuator of the pumping mechanism—on the resultant pulsation behavior. To this end, two distinct lobe configurations are modeled and subjected to comparative numerical analysis: a conventional straight-profiled lobe and an alternative design featuring a helically inclined profile. The principal objective is to elucidate the role of helical inclination in modulating pulsation intensity, while simultaneously evaluating its practical implications—both advantageous and detrimental—for industrial applications. To ensure fidelity to real-world operational conditions, an unsteady (transient) flow regime is employed in the computational fluid dynamics (CFD) simulations.
To facilitate a comprehensive assessment, strategically positioned monitoring points are established at critical locations within each pump, including the inlet, outlet, and internal control volume. At these loci, time-resolved measurements of pressure and velocity pulsations are acquired, enabling a detailed characterization of internal flow dynamics. The analysis extends beyond a mere pointwise comparison; it encompasses a spatial evaluation of pulsation phenomena throughout the internal flow field of each pump configuration. Given the transient nature of the simulated data, advanced time-series regression techniques are utilized to ensure quantitative robustness in the interpretation of results. The findings reveal that the geometric configuration of the lobes—particularly the helical inclination—exerts a substantial influence on the pulsation characteristics of the pump. These effects are subsequently analyzed in both temporal and spectral (frequency) domains, and the implications are discussed comprehensively in the concluding section of the paper.
Read the full research paper.
