| Three-dimensional（3D）finned tube,especially,the 3D rectangular-finned tube was deemed to have significant heat transfer enhancement performance.In some industrial fields,for instance,the gas-solid two phase flow overflowing the heat exchanger of waste heat recovery.The wall of heat exchanger would be eroded after impacted by a good many particles for a long time,and the erosion on the wall surface of finned tube will take harmful influence on the heat transfer and operating of heat exchanger.However,few investigation about flow,heat transfer and erosion characteristics of 3D rectangular-finned tube was reported,therefore,this paper was mainly concentrating on the study of flow,heat transfer and erosion characteristics of 3D rectangular-finned tube or tube bank by using numerical simulation methods.For the study of flow and heat transfer characteristics of 3D rectangular-finned tube,the effects of heat transfer between particles and wall surface of finned tube was neglected,and the gas-solid two phase fluid was replaced by the pure air for the convenience.Some performance parameter curves such as the Nusselt number（Nu）,the total pressure drop（?P）,friction factor（f）,the performance evaluation criteria（PEC）and some velocity contour were obtained.Especially,the correlations of Nu and f were fitted for the engineering application;for the study of erosion characteristics of 3D rectangular-finned tube,the gas phase and solid phase were treated as continuous fluid and discrete phase,respectively.The trajectories of particles were predicted by solving the equations of particle motion and Stochastic Trajectory Model,and the erosion rate of wall surface of finned tube was calculated by using erosion model and restitution coefficient equations.The trajectories colored by the particle velocity,the average erosion rate on parent tube of 3D rectangular-finned tube and smooth tube,the average erosion rate on parent tube of 3D rectangular-finned tube versus Reynolds number Re,fin height Fh,fin width Fw,fin thickness Ft,fin pitch in the axial direction Fp,transverse tube pitch S1 and longitudinal tube pitch S2 were obtained.The conclusions of this paper were summarized as follow:（1）Increasing fin height,fin width or reducing fin pitch in the axial direction,the heat transfer ability and the flow loss of 3D rectangular-finned tube increased and the average erosion rate of parent tube of 3D rectangular-finned tube decreased;the flow loss increased with the increase of fin thickness,the heat transfer ability increased with the fin thickness at high Re and there is no significant heat transfer enhancement at low Re;compared with smooth tube,increasing fin height,fin width,fin thickness or decreasing fin pitch in the axial direction,the Nu increased 21.02%-106.27%,47.61%-97.52%,37.91%-76.74%and 29.81%-96.37%,respectively.The?P increased51.55%-116.41%,66.85%-108.51%,59.76%-98.16%and 37.37%-139.46%,respectively.The average erosion rate of parent tube decreased 6.65%-20.1%,10.5%-20.1%,12.9%-37.3%and 2.74%-29.2%,respectively.（2）The average erosion rate of parent tube of 3D rectangular-finned tube was less than smooth tube under the same conditions;the overall erosion rate and distribution range of erosion increased with the increase Re or dp;there is no significant difference of distribution range of erosion between 3D rectangular-finned tube and smooth tube.（3）The correlation of Nu and f were fitted.（4）Increasing the number of tube rows decreased the transfer ability and increased the flow loss of finned-tube bank,there is an optimal number of tube rows to minimize the wear of tube bank;increasing longitudinal tube pitch or decreasing transverse tube pitch was beneficial to the enhancement of heat transfer and comprehensive performance,but also increased the flow loss and erosion of wall surface;the heat transfer ability,flow loss and the erosion rate of staggered 3D rectangular-finned tube bank were higher than aligned 3D rectangular-finned tube bank under the same conditions;the average erosion rate of parent tube of the first row of staggered 3D rectangular-finned tube bank is the same as aligned tube bank,no erosion occurs on the second row of the aligned 3D rectangular-finned tube bank;the maximum erosion rate occurs on the first row of aligned 3D rectangular-finned tube bank,however,the minimum erosion rate occurs on the first row of the staggered 3D rectangular-finned tube bank. |
