Temperature fitting of partially resolved rotational spectra

In this paper we present a method to automatically fit the temperature of a rotational spectrum. It is shown that this fitting method yields similar results as the traditional Boltzmann plot, but is applicable in situations where lines of the spectrum overlap. The method is demonstrated on rotational spectra of nitric oxide from an atmospheric pressure microwave plasma jet operated with a flow of helium and air, obtained with two different methods: laser induced fluorescence and optical emission spectroscopy. Axial profiles of the rotational temperatures are presented for the ground NO X state and the excited NO A state

Electrohydrodynamic flow in a wire-plate non-thermal plasma reactor measured by 3D PIV method

This work was aimed at measurements of the electrohydrodynamic (EHD) secondary flow in a non-thermal plasma reactor using three-dimensional particle image velocimetry (3D PIV) method. The wide-type non-thermal plasma reactor used in this work was an acrylic box with a wire discharge electrode and two plate collecting electrodes. The positive DC voltage was applied to the wire electrode through a 10 MΩ resistor. The collecting electrodes were grounded. The voltage applied to the wire electrode was 28 kV. Air flow seeded with a cigarette smoke was blown along the reactor duct with an average velocity of 0.6 m/s. The 3D PIV velocity fields measurements were carried out in four parallel planes stretched along the reactor duct, perpendicularly to the wire electrode and plate electrodes. The measured flow velocity fields illustrate complex nature of the EHD induced secondary flow in the non-thermal plasma reactor

Comparison of He-Cd' White-Light Laser Oscillations in Longitudinal and Transverse Hollow-Cathode Tubes

Abstract-The results of a direct comparison of laser oscillations in two different hollow-cathode discharges, i.e., longitudinal and transverse, used for exciting the blue (441.6 nm), green (533.7 nm and 537.8 nm), and red (636.0 nm) lines of the Cd+-ion in an He-Cd mixture are presented. The design of the discharge tube, which allows a direct comparison of the laser properties of both discharges in the same hollow-cathode segments and laser cavity is shown. The results showed the superiority of the longitudinal hollow-cathode discharge in generating the blue, green, and red lines simultaneously. The transverse hollowcathode discharge more efficiently generates the green lines if the other laser lines are absent. This suggests the application of the longitudinal hollow-cathode discharge for white-light He-Cd+ lasers

Elongated DBD with floating interelectrodes for actuators

In this paper the use of a floating interelectrode for dielectric barrier discharge (DBD) plasma actuators applied in aerodynamics is described. The velocity profiles of airflow generated by a single-DBD actuator with the floating interelectrode are presented. Also double-DBD and multi-DBD plasma actuators with floating interelectrodes were investigated to get a longer DBD on a dielectric surface. Obtained results show that the DBDs with floating interelectrodes are capable of extending the plasma area on the dielectric surface. The airflow induced by the successive DBD sets with floating interelectrodes in the multi-DBD actuator had the same direction enhancing the net airflow. The airflow velocity produced by the investigated multi-DBD actuator was up to 10 m/s. This suggests that multi-DBD actuators with floating interelectrodes can be attractive for many aerodynamic purposes

Multi - DBD actuator with floating inter - electrode for aerodynamic control

In this paper the use of a floating inter-electrode in a multi-DBD (dielectric barrier discharge) plasma actuator is described. The multi-DBD plasma actuators with floating inter-electrodes were investigated to get a longer DBD on a dielectric surface and to maximise generated net airflow. Our actuator was used to control the boundary layer flow separation around NACA0012 airfoil model. The results of our investigations suggests that multi-DBD actuators with floating inter-electrodes can be attractive for aerodynamic purposes

Instantaneous and time-averaged velocity fields in a wide electrostatic precipitator

National audienceThis work was aimed at clarifying whether the electrohydrodynamic (EHD) flow in a relatively wide electrostatic precipitator (ESP) (width:height = 2) is 2- or 3- dimensional (3D). The previous our measurements of 3D timeaveraged flow velocity fields suggested that the flow in the ESP duct centre is almost 2-dimensional. In this paper we present both the 3D instantaneous and time-averaged flow velocity fields in a relatively wide ESP (width:height = 2). The ESP used in this work was an acrylic parallelepiped with a negatively polarized wire discharge electrode and two plate collecting electrodes. The velocity field was measured using Particle Image Velocimetry in the observation midplane along the ESP