New technological solutions for restoring the inner surface of hydraulic cylinders

Relevance. Agricultural machines widely use hydraulic cylinders for various auxiliary and working movements. Operation in harsh field conditions leads to the failure of the hydraulic cylinder mirror and, as a result, to the loss of force on the cylinder rod. The development of technological solutions for the restoration of the inner surface as a more appropriate solution in repair production is relevant.Methods. Studies of the heat flow using the “Fluke Ti32” thermal imager and ofthe influence of gas-dynamic spraying (GDS) modes on the adhesive and cohesive strength when using a new design of the nozzle part of the GDS equipment were carried out.Results. The suitability of usage of new nozzle design for GDS in order to restore the inner surface of the hydraulic cylinder body has been established. The elongated and curved nozzle for installations of the “Dimet” type practically does not change the temperature regime of spraying. The adhesive and cohesive strength of the coatings obtained with the new nozzle design is sufficient to operate under conditions characteristic of the inner surface of the hydraulic cylinder body.

New insights on manipulating the material removal characteristics of Jet-Electrochemical machining through nozzle design

Jet-Electrochemical machining (Jet-ECM) is a novel variation of traditional electrochemical machining in which electrically conductive material is removed through anodic dissolution by means of a fine jet of electrolyte. In this study, the effect of nozzle geometry on material removal characteristics are investigated through physical experiments performed on a Jet-ECM system under development at the university of Manchester. A total of 8 nozzles with holes encompassing converging, diverging and rounded features are studied at flow rates between 0.125 and 0.225 l/min. The results show that the nozzle hole geometry has a significant effect on the machined profile produced due to variations in flow velocity, pressure, and electric current distribution with converging hole nozzles providing an increased depth of cut than the symmetrical cylindrical channel by up to 9.7%. A 2D Star CCM+ simulation is also proposed, and numerical results developed and compared with experimental ones to investigate the feasibility of using simulation to develop future nozzle designs. The simulated results show good profile comparison to the experimental results, however, the model needs developing to improve the process repeatability for future use in nozzle design.

Response Surface Methodology (RSM) Approach for Optimizing the Actuator Nozzle Design of Pressurized Metered-Dose Inhaler (pMDI)

Recently, a remarkable scientific interest in the inhalation therapy for respiratory disease was spiked attributed to the growing prevalence of asthma, chronic obstructive pulmonary disease (COPD), and coronavirus disease 2019 (COVID-19) pandemic. A pressurized metered-dose inhaler (pMDI) is the best option by providing fast and efficient symptomatic relief within the lung. However, the rapid development of new inhalation devices could be critical in this competitive environment, and optimizing the inhalation devices could be costly and time-consuming. Therefore, the computational fluid dynamic (CFD) approach was used to shorten the development time. In this study, response surface methodology (RSM) in ANSYS version 19.2 was introduced to discover the optimal design for the actuator nozzle to increase the performance of pMDI. Three (3) parameters (orifice diameter, length, and actuator angle) were optimized, and the best design was selected according to the analysis of particle tracking. The analysis of spray plume was also conducted and compared to analyze the spray plume characteristic produced by three designs. The result showed that RSM generated three (3) models for the new design of the actuator nozzle (Design A, Design B, and Design C). Among three (3) designs, actuator nozzle design C showed the highest injection particle number (232457) and the only one that produced maximum particles velocity magnitude in the acceptable ranges (35.67m/s). All three designs showed a similar pattern as maximum particle velocity magnitude decreased along the axial length until they match the air velocity (0.03-0.04 m/s). Furthermore, the spray plume length, angle, and width were observed to increase linearly with the decreasing maximum particle velocity magnitude. Thus, this study suggested that design C might have the potential as a new actuator nozzle to develop future pMDI to relieve the respiratory condition.

Aerodynamic Design Optimization of a Variable Geometry Nozzle Vane For Automotive Turbochargers

An aerodynamic design optimization study of the nozzle vane of a variable geometry turbine (VGT) turbocharger for a diesel engine application was conducted using the commercial software, ANSYS CFX and DesignXplorer. The nozzle design was optimized at three critical engine operating points. The nozzle shape was parameterized using key design parameters including theta angle, thickness value and opening angle. For a good balance of computational time and accuracy, the optimization approach adopted meta-models and response surfaces to represent the training data and reduce the number of simulations required to reach an optimal design. Finally, more than 300 optimized designs were simulated to assess the performance and characteristics of each design. The final optimized nozzle design met all the design constraints and showed an improvement of up to 2% efficiency and reduced the maximum torque by 20% compared to the baseline nozzle.

Development of converging-diverging multi-jet nozzles for molten smelt shattering in kraft recovery boilers

The effective shattering of molten smelt is highly desired in recovery boiler systems. Ideally, shatter jet nozzle designs should: i) generate high shattering energy; ii) create a wide coverage; and iii) minimize steam consumption. This study proposes a novel converging-diverging multi-jet nozzle design to achieve these goals. A laboratory setup was established, and the nozzle performance was evaluated by generating jet pressure profiles from the measurement of a pitot tube array. The results show that the shatter jet strength is greater with a large throat diameter, high inlet pressure, and a short distance between the nozzle exit and impingement position. Increasing the number of orifices generates a wider jet coverage, and the distance between the orifices should be limited to avoid the formation of a low-pressure region between the orifices. The study also demonstrates that an optimized converging-diverging multi-jet nozzle significantly outperformed a conventional shatter jet nozzle by achieving higher energy and wider coverage while consuming less steam.