To investigate the variations in the flow field of centrifugal pumps with different cavitation numbers, this study utilized the shear stress transport k–ω turbulence model and Zwart–Gerber–Belamri cavitation model to examine the correlation between stall vortices and cavitation flow. The findings indicate that cavitation consistently coincides with the formation of stall vortices, and the distribution of cavitation mirrors the pattern of stall vortex structure. Cavitation tends to develop and aggregate around stall vortices, obstructing a significant portion of inlet areas within the flow channel. As the cavitation number decreases, both the area and intensity of stall vortices increase. For cavitations margins σ = 0.41, 0.23, and 0.15, we observed propagation frequencies of stall vortices at fs = 2.7, 1.8, and 0.9 Hz respectively, as these frequencies decrease relative to impeller movement until reaching near-stationary states. The pressure pulsations in various flow channels exhibit distinct phase differences; smaller cavity numbers result in larger phase disparities along with a gradual reduction in pressure pulsation amplitude. These discoveries present effective strategies for controlling and reducing both cavity formation and pressure fluctuations within centrifugal pumps, thereby enhancing overall stability.

Silt removal is crucial for maintaining navigable waterways in harbors. Jet pumps, without moving parts, are highly suitable for underwater operations such as channel dredging in port environments. Despite their structural advantages in slurry handling, the prolonged transport of solid–liquid two-phase flows can lead to wear on the wall materials, resulting in decreased efficiency and potential pump failure. The wear characteristics of the jet pump walls due to sand particles of varying grain sizes were experimentally investigated. The characteristic of the sands having a higher distribution above the axis as they enter the jet pump was captured by a high-speed camera. The experiment recorded the variations in mass loss at different sections of the jet pump over a period of 120 h, identifying that backflow within the throat region is a significant contributor to wall wear. Scanning electron microscopy was employed to examine the microstructure of the abraded pump surfaces. It was found that there are noticeable differences in the surface wear microstructure across various pump areas, and that particles of different grain sizes result in distinct wear patterns on the pump surfaces. The underlying causes of this phenomenon were discussed from the perspective of particle motion.

The fundamentals of the design and operation of self-priming pumps, as indispensable equipment in industry, have been the focus of research in the field of fluid mechanics. This paper begins with a comprehensive background on self-priming pumps and gas-liquid two-phase flow, and it outlines recent advances in the field. Self-priming pumps within the gas-liquid two-phase flow state and the spatial and temporal evolution of the transient characteristics of self-priming pumps determine the self-priming pump self-absorption performance. Through mastery of the self-absorption mechanism, high-performance self-absorption pump products can be formed to provide theoretical support for the development of products. In current research, numerical simulation has become an important tool for analyzing and predicting the behavior of gas-liquid two-phase flow in self-priming pumps. This paper reviews existing numerical models of gas-liquid two-phase flow and categorizes them. Reviewing these models not only provides us with a comprehensive understanding of the existing research but also offers possible directions for future research. The complexity of gas–liquid interactions and their impact on pump performance is analyzed. Through these detailed discussions, we are able to identify the challenges in the simulation process and summarize what has been achieved. In order to further improve the accuracy and reliability of simulations, this paper introduces the latest simulation techniques and research methodologies, which provide new perspectives for a deeper understanding of gas-liquid two-phase flow. In addition, this paper investigates a variety of factors which affect the operating efficiency of self-priming pumps, including the design parameters, fluid properties, and operating conditions. Comprehensive consideration of these factors is crucial for optimizing pump performance. Finally, this paper summarizes the current research results and identifies the main findings and deficiencies. Based on this, the need to improve the accuracy of numerical simulations and to study the design parameters in depth to improve pump performance is emphasized.

Steel gates are widely used in river and sea engineering to ensure water retention and flow regulation. Due to the attachment and the alternation of dry and wet environments, water retention easily causes corrosion and destruction, while the attachment is mainly cleaned manually at present. Based on stable adsorption, wall adaptability, and movement ability, a split four-track cleaning robot was developed. The split structure combined with a body swing and torsion mechanism can increase the degree of freedom of attitude adjustment and realize stable crawling of the curved panel. Considering the impact force of the water jet during cleaning, mechanical analysis of robot instability and driving torque on a curved surface was constructed to solve the problem of safe adsorption and flexible movement. A remote control system is constructed to complete the cleaning operation, and the coordination relationship between cleaning and crawling speed is analyzed. The performance test results show that the robot can crawl flexibly and stably on a curved surface, and the crawling speed can be greater than 0.052 m/s when the load is less than 5 kg. A continuous cleaning process has an obvious effect on silt and shellfish attachments, and the robot can meet the actual operational needs. The design process can help in the development of this kind of robot.

A small‐scale coating thickness detection robot with remote wireless control was developed to solve the problems of high labor intensity, safety hazards, and lack of special automated equipment for plane steel gate panel coating thickness detection. The robot adopted a chain mechanism and permanent magnet to realize the adsorption crawling on vertical panels, and a 180° reversible detection bench was designed to realize the conversion between panel coating thickness detection operation and panel cleaning operation. The operation flexibility was improved by the x‐axis and z‐axis movement control mechanism; it made the robot capable of adjusting the detection position while parked. The main crawling posture of the robot on the panel was analyzed, and the magnet adsorption force and crawling driving torque were determined. The remote control system was designed, and the robot crawling, detection position adjustment, camera screen, and data transmission display, and so on, could be controlled by the control page, making the robot easy to operate. Finally, it was verified that the detection robot can stably adsorb and crawl within the load of 2 kg, the error of coating thickness detection does not exceed the allowed range of 5%, and the surface of the panel after brush cleaning can meet the requirements of the detection. The stability and accuracy of the detection robot can meet the actual needs of plane steel gate panel coating thickness detection, can replace manual operation to reduce labor intensity and safety hazards, and further enhance the development process of intelligent equipment in the water conservancy industry. This study can provide some help for the development and application of this kind of robot.