Numerical Simulation Of Physical Field And Structure Optimization In Swirl Drying Tower

As one of the main equipments of synthetic detergent production, swirl spray dryingtower with rational design has great influence on the performance and energy consumption ofthe synthetic detergent. The numerical simulation method is used in this article to optimize thestructure of swirl spray drying tower, and it has significance for energy saving in the field ofdrying.The three-dimensional physical model of swirl spray drying tower is established andRNG k-ε model、species transport model、discrete phase model、pressure-swirl atomizermodel are used to simulate the physical field of swirl spray drying tower in this paper. Thestructure of the tower is optimized and the rationality of the optimal scheme is verifiedthrough test results. The conclusions are as follows:(1) Three kinds of optimization schemes on the connection between hot air pipe and hotair ring are presented, plane tangent connection between hot air pipe and no-baffle hot air ring,plane tangent connection between hot air pipe and baffle hot air ring, horizontal planeorthogonal connection between hot air pipe and hot air ring. The results of numericalsimulation of hot air volume flow channel show that the relative standard deviation of thethree schemes are29.81%,15.61%and12.94%respectively. Thus it can be found that airdistribution in drying tower is the most evenly distributed with the horizontal planeorthogonal connection between hot air pipe and hot air ring.(2) Two forms of the drying tower are proposed according to different channelarrangement, namely direct spray drying tower and the swirl spray drying tower. Numericalsimulation results show that the hot air in swirl spray drying tower has a high swirl ratio,andcan drive all hot air in tower rotary flow. Because of rotary rising, the residence time of hot airin tower increased, so as to ensure droplets dried sufficiently. (3) The channels export cross section of the swirl spray drying tower are optimized, andreduce export cross section of the channel whose hot air volume flow is relatively large, sothe fluid in tower is more uniform. And the channel hot air volume flow rate standarddeviation is reduced from11.08%to2.18%, and numerical simulation results are in goodagreement with the measured results.(4) Numerical simulations of material atomization are carried out for two kinds ofdrying tower with different channel layout. Comparing drop flow path and droplet velocitygradient in the two kinds of drying tower, it is found that droplet flow in swirl spray dryingtower is best and proves the feasibility of the optimization for drying tower channels.