Synthesis of NO by rotating sliding arc discharge reactor with conical-spiral electrodes

The present work investigates the potential applications of nitrogen oxides(NO_(x)),particularly nitric oxide(NO)and nitrogen dioxide(NO2),generated through discharge plasma in diverse sectors such as medicine,nitrogen fixation,energy,and environmental protection.In this study,a rotating sliding arc discharge reactor was initially employed to produce high concentrations of gaseous NO_(x),followed by the utilization of a molybdenum wire redox reactor for NO2-to-NO conversion.The outcomes reveal that the discharge states and generations of NO_(x) are affected by varying parameters,including the applied energies,frequencies and airflow states(1.3-2.6 m/s are the laminar flow,2.6-5.2 m/s are the transition state,5.2-6.5 m/s are the turbulent flow),and the concentrations of NO_(x) within the arc discharge are higher than that in the spark discharge.Moreover,the concentrations of NO,NO2 and NO_(x) gradually increased,and the concentration ratios of NO/NO2 and NO_(x)/NO2 decreased with increasing the applied energy for one cycle from 14.8 mJ to 24.3 mJ.Meanwhile,the concentrations of NO,NO2 and NO_(x) gradually decreased,and the concentration ratios of NO/NO2 and NO_(x)/NO2 first decreased and then increased with increasing the applied frequencies from 5.0 kHz to 9.0 kHz.Further,the concentrations of NO,NO2 and NO_(x) gradually decreased,and the concentration ratios of NO/NO2 and NO_(x)/NO2 first increased and then decreased with increasing the air flow speeds from 1.3 m/s to 6.5 m/s.Lastly,the concentrations of NO increased and NO2 decreased with increasing temperature from 25°C to 400°C using molybdenum converted.These findings provide experimental support for the application of plasma in the fields of medicine,nitrogen fixation,energy and environmental protection.

Characteristics of water volatilization and oxides generation by using positive and negative corona

The physical and chemical properties have significant differences for the positive and negative charged particles generated by discharge.In this work,a positive and negative corona discharge system was established,and two discharge reactors for charged particles restraining and acting were designed by a needle electrode covered with a quartz tube and a plate electrode filled with water.The corona discharges happened within the needle-plate electrodes were excited by a positive and negative high voltage source,and the characteristics of both water volatilization and oxides generation were examined within influence of the distances of both quartz tube inside and outside.The results show that the characteristics of both the water volatilization and oxides generation can be affected by the distances of both quartz tube inside and outside.When the distances of tube inside were increased from 5.00 to 13.00 mm,the water volatilizations decreased under negative corona,and increased firstly and declined immediately under positive corona.The maximum value of the water volatilization appeared in the distances of tube inside with 6.00–8.00 mm.In addition,the concentrations of the HNO_(x) and H_(2)O_(2)in treated water decreased with increasing the distances of tube inside.Moreover,with increasing the distances of tube outside from 4.00 to 14.00 mm,the change trends of both the water volatilizations and oxides presented the same as the distances of tube inside,and the maximum value of the water volatilization and oxides appeared in the distance of tube outside with about 9.00 mm.Overall,the positive corona can generate more water volatilizations and oxides in water than negative corona,and non H_(2)O_(2)can be produced by negative corona.The results reflect the difference between positive and negative corona interaction with water,which can provide reference for plasma application.

Study on prediction model of cavitation erosion incubation period of duplex stainless steel surfacing layer in a benign medium

In order to estimate the cavitation incubation period of duplex stainless steel(DSS)under ultrasonic cavitation erosion(CE),this paper analyzed the loading process of material during ultrasonic CE.Local strain theory,cumulative damage theory,and Bernoulli probability model were used to derive the minimum number of cavitation impacts required for the initiation of fatigue cracks,and the predictive equation of the material cavitation incubation period was given.DSS was obtained by tungsten inert gas welding(TIG)powder surfacing method.Tensile test and ultrasonic CE test were performed,and the tensile test data were used to calculate the cavitation incubation period by using the predictive equation.Due to the possible presence of precipitates and micro-cracks in the sample,there was an error between the calculated and the test results.The results showed that the max error between the calculated results and the test results was 8.1%,and the errors of the remaining two groups were within 3.5%.