Design And Research Of High-performance Air-supply Type Laboratory Fume Hood

The laboratory fume hood is an important experimental equipment in the chemical laboratory.Its main function is to effectively control the harmful gas generated during the experiment and discharge it out of the cabinet to ensure the health and safety of the operators and the indoor environment.At present,the existing ordinary fume hoods have some shortcomings.The main manifestations are:turbulence is easily generated in the cabinet,which causes harmful gases to stay and cannot be discharged in time,which reduces the performance of the fume hood;when the exhaust air volume of the fume hood is too large,local Ventilation affects the indoor ventilation system,causing excessive local exhaust and breaking the balance of indoor ventilation.To this end,according to the new requirements of experimental environmental protection,the design and research of high-performance supplementary air experimental fume hoods were launched.First,in the analysis of the relevant research status of domestic and foreign experimental fume hoods,the design requirements and overall layout of the new fume hoods are clarified,and the ergonomics analysis of the fume hoods is carried out to obtain the optimal height of the operating surface and the height direction dimensions of the moving window;The factors affecting the performance of the fume hood are analyzed,including internal exhaust slits and diversion,the shape and position of the movable sliding window and its opening size,the position and size of the air supply,and the location and space of the fume hood.Different experimental equipment occupies external factors such as the position in the fume hood and personnel activities outside the fume hood.Secondly,starting from the internal airflow organization form of the laboratory fume hood,carry out numerical simulation theoretical analysis,select the optimal model,use SF6 as the tracer gas,use SolidWorks to establish a three-dimensional model,and the computational fluid dynamics software FLUENT to analyze the fume hood under different air supply volumes.Diffusion of internal pollutants.The results show that the upper air supply outlets inside the fume hood have too much influence on the concentration of pollutants on the operating surface,and they directly carry pollutants to the vicinity of the operating surface,which seriously endangers the safety of the operators and should be cancelled.Only the air supply ports on both sides of the fume hood should be retained;The position of the air supplement on both sides must be in front of the pollutant release position,close to the operating surface;the maximum air supplement must be strictly limited.Third,in order to achieve the purpose of effectively controlling the diffusion of pollutants from the movable sliding window,a wind curtain wall is planned and designed on the movable sliding window to block the escape of experimental exhaust gas through the operating surface.Through simulation analysis,when a small amount of SF6 diffuses to the vicinity of the operating surface under the condition of 60%makeup air volume and surface wind speed of 0.5m/s to 0.2m/s,the airflow generated by the air curtain under the moving sliding window can be divided into two forms.Roll the SF6 internally into the fume hood and bring it to the exhaust vent until it is discharged;externally,the indoor air is blocked from the gas in the cabinet,and contact is prohibited.Fourth,the centrifugal fan type and the inertial fan type mobile sliding window embedded air curtain device are designed respectively.The embedded mobile air curtain driven by the centrifugal fan has relatively poor performance,resulting in loss along the way during operation,large energy consumption,and difficult installation of the air pipe;while the embedded mobile air curtain driven by the inertial flow fan has relatively superior performance.The effect of curtain formation is good,which is conducive to the formation of a wind barrier,the effect of controlling pollutant overflow at the operation port of the fume hood is obvious,and its control and installation are convenient.Finally,on the basis of the prototype development,the performance test of the embedded mobile air curtain device was carried out,and the laboratory fume hood installed with the embedded mobile air curtain sliding window was tested to verify the numerical simulation analysis and structural design.The correctness has achieved the expected results.