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应用商用Fluent软件,采用RNG k-?湍流模型,对波纹板填料内三维气相流场进行了数值模拟研究。结果发现,气体从填料底部进入后,大部分气体流入波纹板波谷,并沿波纹板倾角方向流动,此时气体流速较大,压降较小;小部分气体在波纹板波锋区域流动,方向曲折向上,气体流速较小,压降也较大;不同气体动能因子下填料的干板压降模拟值与Billet模型预测值、文献实验数据吻合较好;在理想波纹板填料模型中,气体沿波纹板倾角方向流动碰到塔壁时,转向相邻板片波纹倾角的方向流动,实际应用中容易出现壁流现象。本研究对波纹板填料结构改型及应用具有重要指导意义。 相似文献
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采用周期性边界条件对大体积Mellapak350填料内部三维气体流场进行数值模拟研究。结果发现:气体在波纹板波峰、波谷和开孔处均有流动,在波纹板波谷处,气体流速较大、压力较小、湍动能较大;在波纹板波峰处,气体流道复杂、受干扰较大,气体流速较小、压力较大、湍动能较小;模拟计算的填料干板压降模拟值与经验关联式计算值误差在14%之内,吻合较好。 相似文献
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The rheological properties of salt-tolerant partially hydrolyzed polyacrylamide(HPAM)solutions with molecular of 2.5×107 g/mol at different concentrations were measured in steady-state shear flow mode by Haake Rheostress 150 rheometer.Three constitutive equations(Oldroyd four constant model,Guesekus model and FENE-P model) were used for describing the apparent viscosity and first normal stress difference.The apparent viscosity of salt-tolerant HPAM solutions appears a first Newtonian zone when the shear rate is approximately lower than 0.2 s-1.At high shear rate,the HPAM solutions show shear-thinning and elasticity.The results show that the FENE-P model has the best agreement between theoretical and experimental data within the available shear rate range.The material parameters are useful for numerical analysis of polymer solution flow fields. 相似文献
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双螺带桨Metzner常数的模拟计算 总被引:3,自引:0,他引:3
Using the multiple reference frames (MRF) impeller method, the three-dimensional non-Newtonian flow field generated by a double helical ribbon (DHR) impeller has been simulated. The velocity field calculated by the numerical simulation was similar to the previous studies and the power constant agreed well with the experimental data. Three computational fluid dynamic (CFD) methods, labeled Ⅰ, Ⅱ and Ⅲ, were used to compute the Metzuer constant k5. The results showed that the calculated value from the slop method (method Ⅰ) was consistent with the experimental data. Method Ⅱ, which took the maximal circumference-average shear rate around the impeller as the effective shear rate to compute ks, also showed good agreement with the experiment. However, both methods suffer from the complexity of calculation procedures. A new method (method Ⅲ) was devised in this paper to use the area-weighted average viscosity around the impeller as the effective viscosity for calculating k5. Method Ⅲ showed both good accuracy and ease of use. 相似文献
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