Conferce Code PO3018; Abstract submission 1f1157-OR

2021

The book contains data on development of the technologies based on the use of non-stationary electric discharges in plasma jets. Formation of a plasma jet takes place under the effect of non-stationary detonation waves propagating between electrode units. In this case the energy parameters of the plasma can be controlled by a fuel mixture composition, electric potential and geometric characteristics of a device. As a result of interaction with plasma, the treated surface is subjected to pulsed electromagnetic, thermal and elastic-deformation influence. The results of studies of modified layers subjected to pulse plasma treatment are presented. The book describes technologies and equipment that are commercially applied for modification of working surfaces of machine parts and tools. Examples of application of the technologies in metallurgy, mining industry, wood working, machine building and other industrial sectors are given. For engineering and technical workers of machine-building enterprises and institutions specializing in the field of hardening processing of products.

IEEE Transactions on Plasma Science, 2000

The erosion rates for hemispherical electrodes, 2.5 cm in diameter, made of graphite, copper-graphite, brass, two types of copper-tungsten, and three types of stainless steel, have been examined in a spark gap filled with air or nitrogen at one atmosphere. The electrodes were subjected to 50 000 unipolar pulses (25,lls, 4-25 kA, 5-30 kV, 0.1-0.6 C/shot) at repetition rates ranging from 0.5 to 5 pulses per second (pps). Severe surface conditioning occurred, resulting in the formation of several spectacular surface patterns (craters up to 0.6 cm in diameter and nipples and dendrites up to 0.2 cm in height). Surface damage was limited to approximately 80,m in depth and was considerably less in nitrogen gas than in air. Anode erosion rates varied from a slight gain (a negative erosion rate), for several materials in nitrogen, to S ,ucm3/C for graphite in air. Cathode erosion rates of 0.4 gcm3/C for copper-tungsten in nitrogen to 25 Acm3/C for graphite in air were also measured. switch .

Interface Science, 1995

In this paper, an investigation of the impact ionization effects at interfaces between common industrial solid dielectrics and air or insulating oil, under the application of strong, fast rising electric fields (dF/dt 1014 V m -! s -1), is presented. In the prebreakdown stages, the outbreak of partial discharges at an interface may come as the result of impact ionization and plays a very important role in the dielectric aging procedure. Experimental results show that the threshold electric field for the onset of partial discharges is considerably lower in the case of a solid dielectric-air interface, than the corresponding one in the case of a solid dielectric-oil interface. In addition, it is experimentally confirmed that an electromagnetic radiation is emitted. The spectral distribution of this radiation was found to extend up to the ultraviolet region, during the experiments.

DOAJ (DOAJ: Directory of Open Access Journals), 2015

The mechanical properties of wear resistant bicomponent In and Al coatings have been studied. It has been shown that two layer coatings are characterized by plastic deformation, and a bicomponent coat ing is deformed elastically.

AIAA Scitech 2020 Forum, 2020

The effect of a volumetric nanosecond discharge on detonation cell size was demonstrated experimentally in a detonation tube test rig. The experiments were performed in CH 4 :O 2 :Ar=1:2:2 mixture, at initial pressure 180 mbar and ambient temperature. The detonation wave was initiated in a 3.6-m long, 50 × 50-mm 2 square cross section tube, and entered the measuring section where the electrode system was installed to produce a double-pulse discharge ahead of the detonation front. The triggering of the discharge was synchronized with the arrival of the detonation front to the diagnostic chamber. The plasma was generated by two consecutive pulses of −50 and −32 kV amplitude on the high-voltage electrode and 25 ns pulse duration. It was shown that the plasma fills the entire interelectrode space. The analysis of the detonation cell size with and without plasma generation was performed via sooted-plate technique. Production of atoms and radicals in the discharge triggered combustion chemistry decreasing the ignition delay time. As a result, the detonation cell size was reduced by a factor of 1.5 − 2, while passing through the region of the discharge.

Journal of Engineering Physics and Thermophysics, 2013

The mechanisms of action on a high-current spark discharge that make it possible to reduce the total expenditure of electric energy on initiating detonation have been proposed. The action is based on the control of a discharge current with the aid of an external circuit and on the addition of easily ionizable admixtures to a fuel-oxygen mixture. Results of experimental investigations into the spark-discharge initiation of detonation with the action on the discharge process have been presented; the results were obtained in mixtures of hydrogen with oxygen and of commercial propane-butane with oxygen at atmospheric pressure.

Coatings, 2021

The structural-phase state and tribological characteristics of detonation coatings based on Ti–Si–C before and after pulsed-plasma exposure have been experimentally investigated. The authors of the research used a detonation set-up of CCDS2000 to obtain coatings. The modification of coating surfaces was carried out by a pulsed-plasma flow using the “Impulse-6” installation. The results of the research have shown that the modification of coatings surface by a pulsed-plasma effect causes an increase in the microhardness of the surface layer and in its wear resistance. It was determined that after such type of treatment, there is an increase in the content of the Ti3SiC2 phase. According to the results of XRD analysis, the improvement in the mechano-tribological properties of detonation spraying coatings of the Ti–Si–C system as a result of pulsed-plasma treatment is associated with an increase in the content of Ti3SiC2 phases in the coatings, as well as the formation of carbide and ox...

IEEE Transactions on Plasma Science, 2019

Shock Waves, 2005

Development of air-breathing pulse detonation engines is faced with a challenging problem of detonation initiation in fuel sprays at distances feasible for propulsion applications. Extensive experimental study on initiation of a confined n-hexane spray detonation in air by electric discharges is reported. It is found that for direct initiation of spray detonation with minimal energy requirements (1) it is worth to use one discharger located near the closed end of a detonation tube and at least one additional discharger downstream from it to be triggered in-phase with primary shock wave arrival; (2) the discharge area should be properly insulated to avoid electric loss to metal tube walls; (3) discharge duration should be minimized to at least 50 µs; (4) discharge channel should preferably occupy a large portion of a tube cross-section; (5) test tube should be preferably of a diameter close to the limiting tube diameter; (6) gradual transition between the volume with electric discharger and the tube should be used; and (7) a powerful electric discharger utilized for generating a primary shock wave can be replaced by a primary shock wave generator comprising a relatively low-energy electric discharger, Shchelkin spiral, and tube coil. With all these principles implemented, the rated electric energy of about 100 J was required to initiate n-hexane spray-air detonation in a 28-mm tube at a distance of about 1 m from the atomizer.

Por espacio de tes mil años Se queda como un ignorante en la oscuridad Y sólo vive al día Goethe