In response to the problems of high-temperature gas intrusion and ablation in the expansion slit between ceramic tiles under complex flow conditions in the floating-wall combustion chamber, as well as the issue of hooks exceeding their service temperature, numerical simulations and analysis were conducted for this paper. The study revealed the mechanisms of gas intrusion and sealing and proposed two evaluation metrics for evaluating the cooling effect: the maximum temperature of the hook and the proportion of high-temperature area on the sidewall of the tile. Furthermore, the CRITIC weighting method was used to analyze the weight of these metrics. Based on this, the spacing, radius, and length effects on sealing and cooling effectiveness were studied, and multi-parameter calculations and optimization were performed. The results showed that the degree of gas intrusion in the transverse slit was significantly higher than that in the longitudinal slit. In addition, the sealing method of the jet impingement could effectively cool the downstream of both the transverse and longitudinal slit. The spacing of the jet impingement holes had the greatest impact on the cooling effect, followed by the radius and length. Finally, when the spacing of the holes is 10 mm, the length is 18.125 mm, and the radius is 1.6 mm, the cooling effect is optimal, with the proportion of high-temperature area on the side wall of the tile being 20.86% and the highest temperature of the hook reaching 836.02 K.

The article presents the assessment of the levels of radiated electromagnetic interference by commercial UAVs in the context of their popular use for various military tasks. The test was conducted in the frequency range from 30 MHz to 6 GHz, in an electromagnetically anechoic chamber, in accordance with the procedures provided for this type of checks. Apart from the control frequencies (which of course exceed the standards), it can be said that most of the tested UAVs using brushless motors do not exceed the emission levels specified by the military standard MIL-STD-461G. This opens the way to the use of COTS UAV as a carrier of electronic systems for the tasks of recognizing sources of radio signals in the investigated band.

The purpose of this study is to determine the effect of manufacturing conditions on the mechanical properties and structure of ABS parts. Two sets of samples with the same geometric characteristics were produced by fused deposition modelling (FDM) and injection molding (IM). The molding pressure and cooling rate were found to have a significant effect on shaping the mechanical properties and structure of ABS products. The manufacturing method and adopted process parameters have a significant impact on the degree of packing of macromolecules in the volume of the product and thus determine its density. Selected mechanical properties were determined and compared with their specific gravity. The research was carried out using tools and machines, i.e. injection molds of unique design and standard measuring stations. Tensile and bending strengths and Young’s modulus were related to the density of products obtained under different process conditions and having gradient and solid structures. The results provide useful information for engineers designing products using FDM technology. Relating tensile and flexural strength and Young’s modulus to the specific gravity of the product. It was found that the value of product properties is closely related to various process conditions, which further provides a true description of the products.

In this paper, a DC power supply is presented that, in addition to a power factor correction, is equipped with an active power filter function. This function enables compensation of both the reactive and the distortion power, generated by an external load, which is connected to the same power line node as the presented device. A tuneable inductive filter is added at the input of the power electronics controlled current source, which constitutes the main block of the power supply. This filter allows for a visible improvement in the quality of the current source control, compared to a similar device with a fixed inductive filter. This improvement depends on extending the “frequency response” of the current source, which facilitates an increase in the dynamics of changes in the input current of the power supply. The actual modification to the presented device is related to its control section, which is equipped with analogue regulators. The main purpose of this work is to present the results from a simulation model of an electrical system with a power supply, especially compared to those from a similar device but with a discrete control. The work represents a continuation of a research cycle on DC power supplies that are equipped with a power compensation function and are based on tuneable magnetic devices.

This study investigates the use of a thermopressor to achieve highly dispersed liquid atomization, with a primary focus on its application in enhancing contact cooling systems of the cyclic air for gas turbines. The use of a thermopressor results in a substantial reduction in the average droplet diameter, specifically to less than 25 μm, within the dispersed flow. Due to practically instantaneous evaporation of highly atomized liquid droplets in accelerated superheated air the pressure drop is reduced to minimum. A further increase of the air pressure takes place in diffuser. In its turn, this allows for the compensation of hydraulic pressure losses in the air path, thereby reducing compressive work. Experimental data uncover a significant decrease in the average droplet diameter, with reductions ranging from 20 to 30 µm within the thermopressor due to increased flow turbulence and intense evaporation. The minimum achievable droplet diameter is as low as 15 µm and accompanied by a notable increase in the fraction of small droplets (less than 25 µm) to 40–60%. Furthermore, the droplet distribution becomes more uniform, with the absence of large droplets exceeding 70 µm in diameter. Increasing the water flow during injection has a positive impact on the number of smaller droplets, particularly those around 25 μm, which is advantageous for contact cooling. The use of the thermopressor method for cooling cyclic air provides maximum protection to blade surfaces against drop-impact erosion, primarily due to the larger number of droplets with diameters below 25 μm. These findings underline the potential of a properly configured thermopressor to improve the efficiency of contact cooling systems in gas turbines, resulting in improved performance and reliability in power generation applications. The hydrodynamic principles explored in this study may have wide applications in marine and stationary power plants based on gas and steam turbines, gas and internal combustion engines.