| Since dust explosion accident about Harbin flax plant happened after the founding of new China, dust explosion accidents have always been a serious problems under public spotlight.However; most researchers now focus many on coal dust explosion in mine.Basing on the fact that production of industrial powder in a large scale and vigorous development processing in both pharmaceutical industry and foodstuff industry,which had given rise to a huge of accidents in succession, Based on the background of those,The paper, with an attempt to study dust explosion in pipe, The study object is clavulanate potassium and microcrystalline cellulose(1:1) mix dust, a kind of material which constitutes the main ingredients of prevalent anti-inflammatory drugs. Dust explosion influence factors in pipes,explosion combustion velocity, basic flow development parameter features,rule and forming condition of mix dust explosion had been studied, Airflow and flow field characteristics before dust explosion were investigated in horizontal pipeline.Firstly, from the start of the causes about dust explosion in pipes,By theoretical analysis, Influence factors about dust explosion, which is generated from three level indicator, gas flow mode, gas-powder coupling effect, condition and energy of the ignition source. Combustible gas concentration, Oxygen or asphyxiant gas concentration, initial airflow pressure in pipe, tube temperature,gas humidity, air flow, dust clouds of dust cloud area, the degree of uniformity, the dust cloud turbulence, ignition spark shape,which is ten level two influence factors. Clavulanate potassium mixed dust explosion factors model had been derivated in theory. and clavulanate potassium mixed dust explosion combustion velocity model is induced by the conservation law.Using20L spherical explosion test system, dust ignition temperature tester, dust cloud ignition temperature test instrument and so on, clavulanate potassium mixed dust moisture content, particle size distribution, minimum ignition temperature of dust layer, minimum ignition temperature of dust cloud, explosion limit, explosion index, heat transfer characteristics had been researched. Characteristicof potassium clavulanate mix dust explosion basic parameters had been studied. In the thermal explosion balanced method,mix dust explosion limit prediction model had been studied. To base on study at dust particles in explosive parameters, combining with the actual production process,The relationship between dust explosion effect and moisture content,gas pressure, dust cloud concentration, gas temperature, combustible gas concentration, inert gas concentration,other environmental parameters,had been studied.Dust explosive experiment platform of horizontal transport and ventilation pipe had build, according to the characteristic of dust explosion.design the multi-functional experimental rigs that is operated under the different air flow, different dust states and position, and differentinhibition entries,etc.Set up high-speed data collecting system and control system, calculating needed strength requirements that is check,To meet dust explosion experiment demand.In order to match with the pressure of the exploding dust and velocity of propagated wave,The transducer of A/D24bit high-frequency pressure had been selected. Dust explosion data collecting and control software of16high-speed channel had been work out, to satisfy such requirements as data transmission and controlling,ignition,etc.On the basis of transportation and horizontal ventilation pipe experimental station, In a single factor test method, item by item, pressure, film thickness, entry pipe length diameter ratio and other factors were tested,The relationship between these factors and dust explosion had mde. Three airflow pipeline experiments of dust explosion were shown respectively,with environment in29℃and87%, Different airflow and dust concentration impacting on forming rule, conditions of dust explosion,and the explosion overpressure development characteristics had been studied. Studies show that dust explosion shock wave piston flow had responsed dust explosion strength and intensity. On the foundation about dust explosion air flow case3,had focused on the study of clavulanate potassium mix dust explosion characteristics under different concentrations. On the basic about strong explosions about clavulanate potassium mix dust, explosion suppression experimental research were conducted, selection calcium carbonate as inhibitors, pressure attenuation effect have been studied about clavulanate potassium mix dust explosion at different injection time. Studies show that,in air flow case3, inhibitors of flow field within500ms had playeded and worked at dust explosion propagation front surface field.According to the experiment platform and theoretical analysis,standard k-s turbulent model,do numerical simulation were used to analyze and simulation on raised dust ventilation and gas flow in pipe, Gas pressure, air velocity magnitude and variation rules had been stuied. The result of flow speed, speed vector. gas pressure, flow turbulence intensity, gas temperature had made under weak shock wave gas and air flow leading to strong dust explosion.analysising on transport or ventilation gas flow field,according to gas solid coupled equations,Combining the discrete phase DPM model,do simulation of the flow in the shock wave,to get the movement rule of dust particles under pipe gas flow organization case3experiment.made up conditions and characteristics about gas wave spread before strong dust explosion in the horizontal pipeline.These reseach had given potassium clavulanate mix dust explosion factors and explosion combustion velocity model, the basic characteristics of mix dust explosion parameters.and had proposed to explosion dust flow formation conditions in pipe, especially under the condition of horizontal pipelines,the rules about dust explosion gas flow intensity, changing,development characteristics about shock wave which were occurs in the pipeline, and gas transmission conditions to lead to dust explosion, which can provide corresponding countenneasures and using for reference for this type of dust processing industry to prevent explosion, inhibit dust explosions.This paper conducts a study of preliminary research and analysis for impact gas flow affecting on sedimentary particles migration, the transmission, distribution characteristics in pipe,But gas flow value and model impacting on dust exposion needs to be further stuied by continue detection for further correction and meet accuracy requirement. |
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