| Medical salt particle atomizer is a kind of medical equipment for the treatment of respiratory diseases.It can atomize salt powder,that can be delivered to the affected area through patients'spontaneous breathing.The current medical atomizer has a simple structure and lack a uniform concentration,and it is easy to accumulate drug on the inner wall and the bottom.All above make the atomization treatment effect non-ideal,and the medicine powder wasted,and even cause the patients feel uncomfortable.Therefore,the study of medical salt particle atomizers to improve the atomization effect has important theoretical and practical value in atomization therapy field.The main research contents and results are as follows:?1?The atomization mechanism and atomization process of the medical atomizer were analyzed,and the atomization concentration distribution of the particles under the ideal condition of the directional wind speed was deduced.The results showed that the higher the dispersion of particle concentration,and the more uniform the atomization concentration,when the larger the turbulence diffusion coefficient,the greater the atomization stroke and the higher the air velocity.On this basis,the physical model and mathematical model of atomization were established by the Euler-Euler multi-phase flow model and k-?turbulence model.The force conditions of gas-solid two-phase in the flow field were analyzed.The main performance indicators of salt powder atomization were established.?2?According to the actual structure of the medical salt atomizer and the gas-solid two-phase rate range,the boundary conditions were set to simulate the gas-solid flow field in the medical salt atomizer.By this,the influence of the atomizer structure and the gas-solid phase on atomizer atomization were analyzed.The results showed that by improving the shape of the atomizing nozzle,the uniformity of the atomization concentration was significantly improved,and the normalized blend strength was improved from 0.359 to 0.174?0 represents complete mixed,1represents complete separated?;when the airflow of the atomizer is injected into the atomizing chamber from the tangential direction,the mixing intensity is 0.242,both in terms of the uniformity of atomization of the salt powder and the atomization rate of the salt powder,as compared with Straight into the bottom of the atomizer is slightly inferior;when the salt powder addition rate is in the range of 1.26×10-8 kg/s to1.39×10-7kg/s,the influence on atomizer atomization concentration uniformity is not obvious;When the gas phase velocity is increased,the uniformity of the atomization concentration is increased,the turbulent kinetic energy in the atomizer is increased,and the atomization rate is also slightly increased.When the gas phase rate reaches 25m/s,the mixing intensity reaches 0.091.?3?Through the establishment of pneumatic system and test system software and hardware platform,the atomization effect test system for medical nebulizer was developed.The signal processing circuit of the ring-shaped electrostatic sensor was mainly designed.The application software of the host computer was designed based on LabVIEW and the test system was implemented debugging.?4?The actual atomization of the medical salt atomizer was watched by optical photographic methods.Through the analysis of the atomization effect,similar conclusions were obtained as compared with the numerical simulation.After the atomizer outlet shape was improved,the atomization effect of the device has been significantly improved.The atomization range has been increased from 55mm to132mm;changing the direction of the gas flow makes the flow field in the atomizer a swirling flow,atomizer atomization produces more agglomerates and there is more accumulation in the atomizer wall,the atomization effect is not ideal;with the increase of the solid phase rate,the atomization concentration uniformity of the atomizer does not change significantly,and the concentration of atomized salt powder is linearly increasing;with the increase of the gas phase rate,the atomization ranges increase obviously,the atomization uniformity of the atomizer is enhanced,and the concentration of the atomized salt powder are decreased. |
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