This article introduces a comprehensive methodology that combines physical prototyping and computational modeling to analyze the hydrodynamics and design of a semi-direct acting solenoid valve for water applications. A transparent, injection-molded valve model was used to experimentally measure diaphragm displacement, which exhibited linear behavior at flow rates up to 10.1 L/min. Beyond this threshold, the diaphragm reached maximum displacement, constraining flow control accuracy. These experimental results informed the creation of a computational domain for detailed CFD analysis, demonstrating strong validation against experimental pressure drop data. The CFD simulations identified critical inefficiencies, such as uneven pressure distribution on the diaphragm due to inlet flow, flow imbalances, and vortex formation within the chamber and outlet channel. These issues were traced to specific design limitations. To address these design flaws, this study suggests optimizing the inlet geometry, implementing a symmetric chamber design, and modifying the outlet channel with smoother transitions to enhance flow control and improve operational efficiency.

This study numerically investigates the flow-induced vibration (FIV) of a single-degree-of-freedom transverse vibration and pivoted rotation of a square cylinder with the Reynolds number (Re) range of 0.7 × 104 to 6 × 104. Different FIV phenomena with Re increasing are reported. In the vortex-induced vibration (VIV) branch, the amplitude and energy harvest efficiency of the transverse vibration are higher than those of the pivoted rotation, and the situation is opposite in the VIV-galloping transition and galloping branches. Checking the wake vortex indicated that the change in the angle of attack caused by the pivoted rotation of the square cylinder was the cause of these phenomena. The most significant feature was that, at the maximum amplitude, a pair of co-rotating vortices (C mode) shed. The transverse vibration had larger vibration amplitudes and lower aerodynamic force and energy harvest efficiency compared with the pivoted rotation in galloping, and the energy harvest efficiency no longer increased with higher Re. The energy harvest efficiency of the pivoted rotation had two outstanding peaks at maximum pivot angles of θmax = 29° and 41.2°, followed by a decreasing trend. For the transverse vibration, the force induced by the vortices cancels each other out so that the energy harvest efficiency almost does not change. For the pivoted rotation, the amplitude, which does not increase, makes it easier for the wake vortex to interact and interfere with the energy harvest procedure.

In the present paper, we investigate the heat transfer through the multilayer wall of aircraft cabins, as this process influences the comfortable conditions created for most passengers and crew members. The numerical modelling results and calculation of a multilayer wall with a hat-stringer in aircraft design are presented. The thermal characteristics evaluation and their relationship with the design parameters were made. The effect of the air layer size on the overall thermal resistance of the multilayer wall, taking into account the geometrical dimensions and properties of the surfaces, was studied. The relative temperature field in the insulation layer, which crosses the hat-stringer elements of the fuselage frame, is calculated. It is shown that the insufficient thickness of the layer of thermal insulation material in the zone of the hat-stringer at low temperatures leads to a significant deterioration in the multilayer wall characteristics, which can worsen the microclimatic conditions inside the aircraft cabin.

Still, there is the problem of the plunger pumps failures due to pollution of the working fluid with mechanical impurities in civil aviation. The article deals with experimental research the change of relative volume flow rate of plunger pump model NP-72M which depends on the working fluid purity. In particular, the negative effect of increasing the particle size of impurities (electrocorundum about 3 μm, 10 μm, 20 μm) and increasing particles concentration (about 25–150 mg/L) with the constant particle size on pump operation has presented. This has manifested in increased wear of rubbing parts and reduced the relative volume flow rate. A visual inspection of the pump parts has carried out, and the most damaged areas have identified

The detailed unsteady turbulent flow inside a centrifugal fan and its downstream pipe was studied using detached eddy simulation (DES) at three flowrates, namely, the best efficiency point (BEP), 0.75BEP, and 1.49BEP. Both the mean and fluctuating flow fields were analyzed on the basis of the root-mean-square value as the indication of fluctuating intensity. Results showed that the pressure fluctuation had the minimum value at BEP, but the velocity fluctuation increased with the flowrate. Most regions inside the centrifugal fan underwent large pressure fluctuation with the magnitude of about 10~20% of p_ref = 0.5 ρu₂², where u₂ is the blade velocity at the impeller outlet. The pressure fluctuation had a maximum value at the impeller side of the tongue tip rather than the stagnation point, and it decreased rapidly along the outlet pipe with magnitude about 1% of p_ref after distance of five pipe diameters. The spectra of hydrodynamic pressure showed conspicuous spikes at the blade passing frequency (BPF) in the volute but not in the downstream pipe. At the downstream pipe entrance, pressure fluctuation spectra agreed with experimental results, showing that hydrodynamic pressure fluctuations were dominant; however, the experimental data showed a much slower decreasing rate due to the acoustic fluctuations.