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Application of Plasma Actuator with Two Mesh Electrodes to Active Control of Boundary Layer at 50 Hz Power Supply

Gnapowski Ernest, Pytka Jarosław, Gnapowski Sebastian, Józwik Jerzy, Tomiło Paweł

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 1

58--63

EN

Numerous studies are conducted to improve the flow in the boundary layer to ensure laminar flow and in particular to increase flight safety. A new solution used to improve the laminar flow is the plasma actuator. The classic configuration of DBD plasma actuators is commonly used with the asymmetric electrode system. The manuscript describes the results of tests with a plasma actuator. Experimental tests were carried out on the built model of the wing with the SD 7003 profile, a plasma actuator was mounted on the upper surface. In contrast to the commonly used solution with solid tape copper electrodes, the novelty in the described research in the manuscript is the use of a large GND electrode (covering 70% of the upper surface of the wing) and a HV mesh electrode. The use of a plasma actuator on the upper surface of the wing affects the air flow in the boundary layer as a result of air ionization. The tests were carried out for a supply voltage from V = 7.0 kV to 12 kV and Reynolds number, Re = 87500 to 240000, flow velocity during the tests in the tunnel was in the range of U = 5-15 m/s and the angle of attack α = 5 -15 degrees. On the basis of the results experimental tests, the percentage change in the lift coefficient was calculated for the switched on and off DBD system. The obtained results indicate a maximum 17% increase in the lift coefficient for the plasma actuator activated for air flow U = 5 m/s and angle of attack α = 5 degrees. In the remaining configurations, changes in the lift coefficient amounted to 4%.

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The Effects of Hot Deformation Parameters on the Size of Dynamically Recrystallized Austenite Grains of HSLA Steel

Gnapowski Sebastian, Opiela Marek, Kalinowska-Ozgowicz Elżbieta, Szulżyk-Cieplak Joanna

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 2

76--84

EN

Materials scientists are seeking to produce metals with reduced weight and dimensions while maintaining the appropriate mechanical properties. There are several ways to improve the internal structure of metals, such as the ultrasound used to solidify liquid metal. The homogeneity of the grains and the uniformity of the metal structure affects its mechanical strength. This paper presents the results of investigations into the effects of hot deformation parameters in compression on the austenite grain size in the HSLA (High Strength Low Alloy) steel (0.16% C, 0.037% Nb, 0.004% Ti, 0.0098% N). The axisymmetric compression investigations were performed on cylindrical investigation specimens using a Gleeble 3800 thermomechanical simulator with the strain rate of 1÷15.9 s-1 and strain degree ε = 1.2. Before deformation, the research specimens were austenitized at TA = 1100÷1250 °C. The metallographic observations of the primary austenite grains were conducted with an optical microscope, while the structure of dynamically recrystallized austenite, inherited by martensite, was examined by using a scanning electron microscope.

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Metallographic Comparison of Copper and Brass Plasma Reactor Electrodes After a Month of Operation

Gnapowski Sebastian, Kalinowska-Ozgowicz Elżbieta, Pietraszek Aleksandra

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 3

201--209

EN

Many researchers from around the world are looking for better and cheaper means of ozone production. One of the methods of increasing the efficiency of ozone production is the use of a rotating electrode presented in this paper. Experiments were carried out which showed that the most important parameters are the materials used in the electrodes and the condition of their surface. The metallographic investigations of the electrodes after continuous work for a month were made, which show how the raids layers are formed. As a result of working in a highly oxidizing environment, the electrode is oxidized in a process of chemical corrosion. It is obvious that the layer of corrosion products created during the work of the plasma reactor isolates the surface of the electrode, which reduces the intensity of the electric field, causing a decrease in the amount of plasma generated, which reduces the concentration of ozone during this process. The dynamics of the plasma generation process and the type of electrode material working in changing process conditions are the decisive factors influencing the concentration of ozone produced. The influence of the medium, which is the electrode material, depends mainly on its resistance to corrosion in the environment of dynamically changing conditions, e.g. electrode rotation, oxygen flow through the rotating electric field and the month-long working time of the plasma reactor.