# Investigations of Working Characteristics of Transferred Arc Plasma Torch Volume Reactor
## 3 The Results of the Experiment  
Figure 2 shows plasma flow images obtained using a high-speed RedLake MotionPro video camera. By analyzing the images, the electric arc of the ionized gas can be observed to move chaotically inside the volume plasma chemical reactor. An electric arc discharge is generated between the conductive bottom of the reactor, which acts as an anode and the plasma torch. The primary discharge of the electric arc is obtained using a high-voltage 20 kV oscillator. The resulting strong electric field ionizes the plasma-forming gas. After the initial discharge, the electric arc enters the self-discharge phase and is supported by the impact ionization process. Impact ionization requires an additional electron source for which its role is played by the hafnium built into the cathode. The electrons are emitted when a thermoelectric emission phenomenon occurs. Figure 2a-c show the discharge of an electric arc when no material is treated inside the plasma chemical reactor, and the bottom is made of a conductive graphite acting as an anode. By analyzing these images, it was observed that the electric arc moves over the entire surface of the graphite anode. The chaotic movement can be explained by the fact that the arc is formed at the location of the volume reactor where the conditions for impact ionization are mostly favorable. An electric arc occurs where the lowest energy consumption is required to form it. Figure 2d-f show the electric arc discharge when the clay material is mixed with hydroquinone on the graphitic bottom of the volumetric reactor. This material was selected for reactor operation studies and the visual analysis of plasma arc behavior. As we can see in this case, the electric arc moves chaotically. The particles of the treated material are fed by a special dispenser onto the surface of the anode, which is covered with a layer of uneven thickness. Since clay and hydroquinone are poor conductors, the probability of electric arc formation is the greatest at the point where the particle layer is the thinnest. In addition, the movement of the arc is affected by the fact that the particles of the material to be processed melt on the surface of the anode; thus, the thickness of the layer is constantly changing while simultaneously influencing the energy characteristics of the electric arc's formation. In transferred arc torch-type plasma type reactors, there is one constructive problem that the thickness of the anode bottom changes due to the constant interaction with the electric arc. As a result, the service life of the plasma chemical reactor decreases and the energy characteristics of the electric arc formation varies. The thermal characteristics of the plasma chemical reactor were evaluated during the study. A special opening was made in the wall of the plasma chemical reactor through which the temperature distribution profile at the cooled wall of the plasma chemical reactor was measured using the platinum-rhodium thermocouple. The points at which the temperature was measured are shown schematically in Figure 3. The temperature measurement step was 5 mm from one edge of the opening, which is considered as the zero reference point to a distance of 60 mm near the other edge. The very center of the opening is at 30 mm (this is clearly seen in Figure 3). Figure 2: High speed video camera images with a frame exposure time of 1 \(\upmu\)s and frames per second rate of 500 fps: when (**a–c**), there is no material to be processed in the reactor and (**d–f**) is when the reactor is filled with the clay to be treated. Figure 4 shows the measurement results of the temperature profile. The measurements were made using the special hole made in the wall of the reactor mentioned above for measurements. During the temperature measurement, the material was treated inside the reactor. An automatic positioning device was used to change the position of the platinum-rhodium thermocouple nozzle.