| The pneumatic conveying system uses the kinetic energy or pressure energy of the gas to stably and effectively convey the fly ash to the designated location.At the same time,it also has the problems of high energy consumption,high maintenance cost,easy to wear and easy to block.Spiral flow transportation has the advantages of suppressing pipeline blockage and reducing pressure loss.It is widely used in the fields of hydraulic sand transportation and pneumatic coal transportation,but the research on fly ash transportation is relatively scarce.In order to broaden the fly ash transportation technology,firstly,numerical simulation is used to study the influence of the blade profile and blade installation angle of the swirling device on the swirl number and total pressure loss.Secondly,based on the DDPM model,Tabakoff model,soft ball model,etc.,the ash-gas two-phase flow numerical simulation is carried out,and the flow field characteristics of spiral flow transportation under different blade installation angles,mass flow,and inlet speed factors are studied,and the flow field characteristics are compared with axial flow transportation.comparing.The research work in this paper provides a reference for perfecting the design of the swirl generating device and the research of the characteristics of the flow field of the pneumatic conveying fly ash.The main conclusions of the study are as follows:(1)The study of the spiral flow field guided by the S801 airfoil,rectangular and unilateral arc shows that the spiral flow field of the S801 airfoil is 20.53%higher than that of the rectangular and unilateral arc spiral flow fields.8.66%,the total pressure loss decreased by 5.8%and 16.1%.Therefore,the selection of S801 airfoil blades for radial blade spin-off has the advantages of low pressure loss and strong spin-off effect.(2)The study of the influence of blade installation angle and velocity on the spiral flow field shows that when the inlet is 30 m/s,the swirl flow generated by the blade with the installation angle of 20°is compared with the installation angle of 25°,30°,and 30°.The average swirl numbers generated by 35° and 40° increased by 1.38%,6.86%,7.47%,and 17.55%respectively.When the axial velocity is 10 m/s,the average swirl number is increased by 7.49%compared with the 30 m/s velocity.The total pressure loss of the axial velocity of 10 m/s is 0.111 times of the total pressure loss of 30 m/s.Reducing the installation angle can significantly increase the number of swirls,and reducing the inlet velocity can significantly reduce the total pressure loss.(3)The influence of different blade installation angles on swirling fly ash transportation is studied.In spiral flow conveying,the tangential velocity loosens the concentration distribution of fly ash on the pipe section,while the particles sink to the bottom when the fly ash is conveyed in axial flow;the blade installation angles 20°,25°,30°,35°,and 40°,respectively,the particle velocity of spiral flow conveying on the monitoring surface De6 is 6.04%,5.45%,5.93%,3.85%,4.26%higher than that of axial flow conveying respectively,and the total pressure loss of the system is lower than that of axial flow conveying 3.82%、2.77%、1.67%、3.45%、2.77%.Therefore,spiral flow conveying can increase the flow rate of fly ash and reduce the total pressure loss.(4)The influence of fly ash mass flow rate on the conveying of fly ash by spiral flow is studied.The particle velocity of different mass flow spiral flow conveying at the monitoring surface De6 is higher than that of axial flow conveying,which is increased by 8.24%,7.94%,6.24%,4.59%,4.03%,respectively.When the mass flow rate decreases,the total pressure loss of spiral flow transportation is gradually higher than that of axial flow transportation;when the number of swirl flow is close,the particle velocity of spiral flow transportation on the monitoring surface De6 increases with the decrease of mass flow rate;as the mass flow rate decreases The total pressure loss of the spiral flow conveying system is gradually higher than that of the axial flow conveying.(5)The influence of air inlet velocity on the conveying of fly ash by spiral flow is studied.The results show that the number of swirling flow increases with the increase of the inlet velocity,and the maintenance distance also increases obviously;when the inlet velocity increases,the particle velocity of spiral flow and axial flow conveying methods both increase on the monitoring surface De6,and the particles conveyed by axial flow The flow velocity increases faster.When the inlet velocity is less than 17 m/s,the axial flow particle velocity is less than the spiral flow conveying,and the opposite is true when the inlet velocity is greater than 17 m/s.The system pressure loss all presents a change that first decreases and then increases,and the inlet velocity is 15 at m/s and 16 m/s,the total pressure loss of spiral flow transportation is 8.5%and 3.8%lower than that of axial flow transportation.When the inlet velocity is greater than 17 m/s,the total pressure loss of spiral flow transportation is higher than that of axial flow transportation.The research results show that when the mass flow rate of fly ash is greater than 0.5 kg/s and the air inlet velocity is less than 17 m/s,the use of S801 airfoil blades has a good rotation effect,which can increase the transportation speed of fly ash and reduce The total pressure loss plays a role in energy saving and consumption reduction,and has certain application value and practical significance for the transportation of fly ash.Figure[45]Table[8]Reference[74]... |
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