纳米粒子在方管中传输与沉降的研究

采用有限体积法离散并应用Simple方法对方截面弯曲管道内的纳米粒子传输和沉降进行了数值计算,结果表明Reynolds数和Schmidt数是影响纳米粒子传输和沉降的重要参数。粒子较小时,弯管中轴向速度较大的区域就是粒子的高浓度区域,沉降增强因子最大值出现在外弯侧的中心位置;粒子较大时,截面浓度的梯度值降低,沉降增强因子趋于平均,此时整个截面的粒子平均沉降。弯曲作用对于粒子较大且Dean数也较大时的影响更加明显。

Transport and deposition of nanoparticles in square bend tubes

Transport and deposition of nanoparticles in bend tubes with square cross-section are simulated numerically for different Reynolds numbers and Schmidt numbers.A finite-volume code and the SIMPLE scheme are used to solve the equations.The results show that when the Schmidt number is small,the high axial velocity region is also the high nanoparticle concentration region.The maximum of deposition enhancement factor (DEF) appears at the center of the outside of the bend edge.When the Schmidt number becomes large,the gradient of the nanoparticle concentration on the cross-section decreases,the DEF tends to be uniform.The nanoparticles deposit on the whole cross-section averagely.The influence of the curvature is much more notable for the large nanoparticle when the Dean number is high.