This review explores the complexities of integrated rural development, education, and management, focusing on the challenges encountered and the strategies employed to address them. Integrating various sectors and disciplines in rural development initiatives presents unique obstacles, including coordination issues, resource constraints, and stakeholder engagement difficulties. By examining the existing literature and case studies, this review identifies key challenges, such as limited institutional capacity, inadequate funding, and the need for multidisciplinary collaboration. Furthermore, it analyzes strategies such as community involvement, capacity building, and innovative technology adoption to overcome these obstacles. The review emphasizes the importance of tailored approaches considering local contexts and empowering rural communities in decision-making processes. This approach is essential for the sustainability of rural areas because it ensures that interventions are context-specific, culturally appropriate, and resource-efficient, ultimately leading to more effective and sustainable outcomes. By understanding and addressing the challenges while implementing effective strategies, integrated rural development, education, and management can lead to sustainable and inclusive development outcomes in rural areas.

Pump-as-turbine (PAT) technology permits two operating states—as a pump or turbine, depending on the demand. Nevertheless, designing the geometrical components to suit these operating states has been an unending design issue, because of the multi-conditions for the PAT technology that must be attained to enhance the hydraulic performance. Also, PAT has been known to have a narrow operating range and operates poorly at off-design conditions, due to the lack of flow control device and poor geometrical designs. Therefore, for the PAT to have a wider operating range and operate effectively at off-design conditions, the geometric parameters need to be optimized. Since it is practically impossible to optimize more than one objective function at the same time, a suitable surrogate model is needed to mimic the objective functions for it to be solvable. In this study, the Latin hypercube sampling method was used to obtain the objective function values, the Adaptive Neuro-Fuzzy Inference System (ANFIS), Artificial Neural Network (ANN) and Generalized Regression Neural Network (GRNN) were used as surrogate models to approximate the objective functions in the design space. Then, a suitable surrogate model was chosen for the optimization. The Pareto-optimal solutions were obtained by using the Pareto-based genetic algorithm (PBGA). To evaluate the results of the optimization, three representative Pareto-optimal points were selected and analyzed. Compared to the baseline model, the Pareto-optimal points showed a great improvement in the objective functions. After optimization, the geometry of the impeller was redesigned to suit the operating conditions of PAT. The findings show that the efficiencies of the optimized design variables of PAT were enhanced by 23.7%, 11.5%, and 10.4% at part load, design point, and under overload flow conditions, respectively. Moreover, the results also indicated that the chosen design variables (b₂, β₂, β₁, and z) had a substantial impact on the objective functions, justifying the feasibility of the optimization method employed in this study.

To obtain a better insight into the unsteady flow behavior in side channel pumps by a robust vortex identification method, this study presents the efficacy of the new Ω-criterion in characterizing the evolution of vortex structures in the turbulent flows under different time steps. The flow behavior and the underlying vorticity dynamics were revealed as well. Compared to Q-criterion, the new Ω-criterion identified all vortex structures irrespective of the intensity at a universal threshold of 0.52. Three different types of vortex structures (longitudinal, axial, and radial) were identified to be responsible for the turbulent flows in the side channel pumps. The beneficial longitudinal vortex promotes the momentum exchange flow between the impeller and side channel which leads to the high hydraulic head of side channel pumps. On the other hand, the unfavorable axial and radial vortex structures restricted in the impeller passage mitigate the exchange process accounting for the low efficiency of the pumps. From this study, it can be established that the evolution of the axial vortex structures is responsible for the largest vortex distribution in the impeller compared to the total vortex evolved. The impeller outer radius contributes about 60% of the unfavorable axial structures evolved. Using the new Ω-criterion, many reported anomalous findings have been explained.

With continuing demand for high and stable operational reliability of hydraulic pumps, it has become vital to take into account the effects of leakage flows in the side chambers in-between the rotating impeller and the stationary casing. Leakage flows have the potential to produce unsteady flow behavior that inherently leads to substantial vibration, undesirable noise, energy losses, and fatigue of pump components. Thus, the purpose of the present study is to discuss and review the various aspects of these harmful unsteady flow behaviors resulting from leakage flows. The first part deals with the theoretical studies on the boundary layers, core swirl, moment coefficient, and pressure and velocity distribution of rotor–stator flows. Then, a simplified model of the prediction of through-flow on moment coefficient C_m and thrust coefficient C_F with good correctness has been extensively discussed. Finally, a summary of the experimental and numerical studies on rotor–stator cavities is presented in the second part of this study. This review concludes with a discussion of the calculation of axial thrust and moment coefficient during the design process of radial pumps in a more precise manner.

To investigate the unsteady flow characteristics in side channel pumps, the vortex structures and their evolutions in the impeller and side channel flow passages have been comprehensively studied. Systematically, three impeller schemes were designed with different ratios of convex blade height h to impeller blade length l (h/l = 0.2, 0.5, and 0.8) for detailed analysis. The findings indicated that the convex blade broadens the high-efficiency range and improves the efficiency at the best efficiency point (BEP) for scheme h/l = 0.2. Impeller scheme h/l = 0.2 records the highest vortex concentration region, scheme h/l = 0.5 displays as scattered spots, while scheme h/l = 0.8 exhibits significant flow pattern changes in the impeller. The vortex distribution area and vortex intensity in the lengthways between the impeller and side channel of h/I = 0.2 are almost analogous, but the other two impeller schemes have obvious separation and very chaotic. Although the shrinkages of axial vortexes in the impeller did not reflect on hydraulic performance, impeller schemes h/l = 0.5 and 0.8 provided an outstanding performance in reducing the pressure fluctuations. The objective of this study is to provide a theoretical basis for optimal design and analysis of strong vortex flows in side channel pumps.

The momentum flow exchange between the impeller and side channel produces highly turbulent flows in side channel pumps. The turbulent flows feature complex patterns of vortex structures that are partly responsible for the dissipation of energy losses and unsteady pressure pulsations. The concept of turbulent flows in side channel pumps requires a reliable vortex identification criterion to capture and predict the effects of the vortex structures on the performance. For this reason, the current study presents the application of the new Ω -criterion to a side channel pump model in comparison with other traditional methods such as Q and λ ₂ criteria. The 3D flow fields of the pump were obtained through unsteady Reynolds-averaged Navier-Stokes (RANS) simulations. Comparative studies showed that the Ω -criterion identifies the vortex of different intensities with a standard threshold, Ω =0.52. The Q and λ ₂ criteria required different thresholds to capture vortex of different intensities thus leads to subjective errors. Comparing the Ω -criterion intensity on different planes with the entropy losses and pressure pulsation, the longitudinal vortex plays an important role in the momentum exchange development which increases the head performance of the pump. However, the rate of exchange is impeded by the axial and radial vortices restricted in the impeller. Therefore, the impeller generates the highest entropy loss and pressure pulsation intensities which lower the output efficiency. Finally, the findings provide a fundamental background to the morphology of the vortex structures in the turbulent flows which can be dependent upon for efficiency improvement of side channel pumps.