To investigate the connection between nozzle jet performance and structural characteristics (contraction angle θ, outlet diameter d, ratio of straight segment to outlet diameter L2/d), impact force studies were performed on nine nozzles with varied structures using a self-developed water jet experimental platform, with target distances of 20mm, 100 mm, 200 mm, and 300 mm with jet pressures of 0.1 MPa, 0.2 MPa, and 0.3 MPa. The impact force of a nozzle water jet grows dramatically as the outlet diameter increases. When the pressure of the water jet remains constant, the impact force increases as the target distance increases. The maximum water jet impact force is 6.1 KG when the d is 11 mm. The BP neural network, the PSO and the GA-BP neural networks were utilized to forecast and assess the nozzle impact force at a target distance of 300 mm, respectively. The results reveal that, when compared to the PSO and the BP neural network, the GA-BP neural network projected values are more consistent with the measured values, with a lower average error rate and greater predictive capacity.
Laser surface texture and atmospheric plasma spraying technology were used to prepare molybdenum coating on AISI 304 stainless steel substrate. A 3D surface topography instrument was used to extract the groove profile and a quadratic parabola was used to fit the textured groove. Meanwhile, a numerical model was established in which multiple droplets filled a single measured and fitted groove. The solidification, defects, and wall temperature of the coating filled with the groove with droplets were compared with the parabola grooves. The simulation comparison between the fitted groove and measured groove shows that the splat was opening angle increases by 22.95%. The maximum heat flow rate transferred by the groove wall interface decreases by 10.1%. The solidification time trend is the same, whereas the filling splash of droplet fluid is reduced.
Laser surface texturing is an advanced technology which can effectively improve surface tribological properties and has been attracted wide attention. However, the large diameter micro-dimple cannot be finished by fixed-point pulse processing, and fewer researches about the effect of laser scanning strategy on large diameter micro-dimple texture have been reported. Therefore, the effect of laser scanning strategy on the morphology of large diameter micro-dimple texturing is discussed in this work. An experiment of micro-dimple texturing on the 40Cr steel temples is performed by using a nanosecond laser. The effect of laser scanning mode on the micro-dimple texture is investigated to determine a reasonable laser scanning mode. Meanwhile, the influence of scanning interval on the micro-dimple texture with different diameters is studied under the best scanning mode. Results show that the diameter of the micro-dimples which are processed by the fixed-point pulse is about 48.1μm, and the spiral scanning is the best scanning mode for the large diameter micro-dimple texture. For spiral scanning, with the increase of scanning interval, the diameter of micro-dimples increases slightly, while the depth of micro-dimples, the height and the width of craters decreases. In order to ensure that the micro-dimple texture has good formability, the scanning interval can be properly floated on the basis of 10μm, but the scanning interval should not be close to the diameter of micro-dimples processed by the fixed-point pulse.
Due to the serious partial-wear of rods and tubes and a lack of visual simulation system in the oil field, we design a visualization simulation system for the partial-wear of pumping well rods and tubes. The static visualization simulation of well trajectories and tubes, and the dynamic visualization simulation of the sucker rods motion states and the contact state of tubes and rods are realized. The method of reversely seeking the control polygon vertex of cubic B-spline curve is used in the well trajectory curve reconstruction. The method of combining circle division is proposed to solve the problem of translucent and semi-section display of tube with arbitrary 3D well trajectory as the axis. The visualization simulation of the dynamic deformation of sucker rods and the contact state between tubes and rods are realized by combining the real time partial-wear points and the well trajectory data points. The field tests show that the system can identify the position and state of tubes and rods’ eccentric-wear clearly, which provides basis for diagnosis and treatment.
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