Study On Air Flow Characteristics And Application Of Conical Air Inducer

Gas conveying machinery is widely used in factories,tunnels,nuclear power and other fields to achieve the purpose of ventilation,dust removal or cooling.In the process of transporting gas in some special environments,such as scenes with high content of harmful gases such as dust,oil fume or corrosive gas,there will be certain requirements for the transportation equipment.Without corresponding treatment measures,the power unit of the conveying equipment will be damaged to some extent and the performance of the equipment will be affected.Because the jet has the characteristics of high energy density and slow speed attenuation,at present,the local low pressure formed by the gas jet is usually used to drain the polluted gas in engineering to avoid direct contact between the power plant and the drained gas,so as to create a good and safe working environment.Combined with the Coanda effect,a new air inducer is designed in this paper.Taking the conical air inducer as the research object,the air flow characteristics and induction performance of the conical air inducer are studied by numerical simulation.It is found that the conical air inducer can induce the surrounding air flow to concentrate in the front cylindrical area of the conical inducer,and can improve the air flow on the straight line in this area.It has the characteristics of concentrated gas flow and high induced air volume.Based on the research conclusion,further take kitchen smoke exhaust and highway tunnel ventilation as the research background to explore the application effect of conical air inducer in the actual scene.The specific research contents are as follows:(1)The physical model of three-dimensional conical air inducer is constructed,and the air flow mechanism and air flow characteristics of conical air inducer are studied by numerical simulation method;The structural factors affecting the air flow characteristics of conical air inducer(curvature of Konda surface and length of conical inducer)are analyzed.Based on the research conclusion,the structure of conical air inducer is further optimized by orthogonal test to reveal the significant relationship between various factors and inducer,so as to determine the optimal parameters of inducer structure.(2)Place the optimized conical air inducer inside the tube for in-tube gas drainage.The physical model of the in-tube cone air inducer is established,and the air flow field characteristics of the conical air inducer in the tube are studied by numerical simulation method,and the circular jet nozzle is compared with the circular jet nozzle.From the three aspects of velocity field,pipeline inlet and outlet pressure drop and airflow induction rate,the difference between the airflow characteristics of the two is analyzed,which lays the foundation for the application of the inducer in the kitchen smoke extraction system.(3)Study the performance of the inducer instead of the fan as the power device for kitchen smoke exhaust,establish the indoor kitchen physical model,numerically simulate the characteristics of the airflow field of the inducer in the kitchen smoke exhaust system,and explore the influence of the change of induction speed on the exhaust air volume and induction rate;By analyzing the distribution of temperature field and concentration field of smoke exhaust system and indoor kitchen,the effect of oil smoke ejected by inducer is studied.Based on the above research conclusions,the flow field of kitchen under different air inlet conditions is further analyzed to improve the ejector performance of inducer to oil fume.(4)Based on the inducer combined relay model under infinite space,and compared with the circular jet nozzle combination model,the flow characteristics and differences of the two airflow relays are preliminarily studied from the flow field streamline distribution characteristics and velocity field distribution through numerical simulation methods,laying the foundation for the application of inducers in highway tunnel ventilation.The physical model of highway tunnel is established to study the performance of inducers in highway tunnel ventilation,and at the same time to explore the ventilation effect of inducers under different installation conditions,and to reveal the relationship between them and induction rate and boost reduction coefficient to optimize the inducer layout.Based on the conclusions of the study,the CO concentration distribution in the tunnel was analyzed and compared with the circular jet fan to explore the difference between the ventilation performance of the two.