| The industrial production process will be accompanied by the production of a large number of flammable,explosive or toxic gases.in order to prevent the harm caused by such gases,it is necessary to accurately detect the content of such gases.This article uses a combination of simulation ahd experiment methads to study the nano tip,the internal working mechanism and structure optimization of the ionization gas sensor in the field of micron spacing,and the feasibility of this type of sensor to detect CH4 at low concentration,The main research contents are as follows:(1)When the internal working mechanism of this type of sensor is not yet perfect,this article first carried out two-dimensional DC discharge modeling and simulation in the N2-O2 mixed gas space discharge under the nano-tip and micron pitch field,and studied the internal of the sensor The working mechanism and the influence of the electrode spacing on the space discharge:secondly.to optimize the field emission characteristics of the sensor,the dicharge structure is modeled and simulated by a two-dimensional eletrostatic field,and the influence of the bottom electrode rading on the field emission is studied;finally,the electrode spacing is combined The research results have studied the influence of the bottom electrode radius on the space discharge.The simulation results show that as the bottom electrode radius decres,the nanotube body begins to emit secondary electrons,and the space current density first inereses and then decrease.(2)In order to verify the simulation results,first,the sensor was assembled using the TiO2 nanotube film prepared by anodization as the electrode material,a gas discharge experimental system was built and the space discharge of N2-O2 mixed gas at different electrode spacings was expcrimentally verified,the experimenal results show that When the distance is in the range of 30?m?150?m the optimal electrode spacing is similar to the simulation results;then,the space discharge of N2-O2 mixsted gas different bottom electrode radii was experimentaly verified,the exoermental results show that when the sutface area of the anode is the range of 10mm×10mm?50mm×50mm,the optimal bottom electrode radius is similar to the simulation results;finally,the effect of the structure of the sensor before and after optimization on the ionization performance of the space was verified by experiments and it was concluded that the discharge current of the optimized sensor compared to the optimized the front sensor is increased by 1.3 times.(3)There is a risk of explosion due to CH4 discharge,in order to study the feasibility of detecting CH4 at low concentration before and after sensor optimization,this paper mainly conducts a two-dimensional simulation study of CH4-N2 mixed gas with CH4 concentration in the range of 1×103ppm?1×104ppm,the simulation results show that:as the concentration of CH4 increases,the spatial current density of the sensors before and after optimization shows a monotonous increasing trend,and the sensitivity and linearity of the optimized sensor are better than those before optimization.In this paper,the simulation combined with practical application can explain the discharge mechanism from the micro scale,which effectively make up for the shortage of experimental diagnosis and has certain guiding significance for the development and optimization of actual products. |
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