采用无网格格子?玻尔兹曼法(LBM)模拟计算错流换热器流体力学，并与CFD模型对比. 结果表明，结合大涡模拟(LES)，LBM合理预测了错流换热器湍流流体力学，模拟速度分布与文献结果吻合较好，关键物理量计算误差均在工程允许范围内. LBM与CFD模型模拟结果大致相同，计算时间相近，计算效率无明显差异. CFD模型需大量前处理时间用于网格划分，尤其对于具有复杂几何内构件的换热器，网格处理更复杂. LBM基于粒子追踪计算平衡态分布函数的演化，采用格子概念替代原网格，只需指定格子离散尺寸，无需适应几何边界的空间离散，模型适用性更强，建模过程更高效，适合复杂几何结构的模拟.
A meshless approach based on the LBM (Lattice?Boltzmann Method) was employed for simulating a cross-flow heat exchanger. The calculated hydrodynamics was compared with the CFD for discussion. The results showed that the LBM combined with LES predicted the turbulent hydrodynamics of the heat exchanger reasonably. The simulated fluid velocity distributions agreed with the referenced experimental data. The calculation deviations on key physical quantities were also acceptable for engineering purpose. The subsequent comparison indicated that the LBM and CFD had almost the same calculation results and cost. There was no apparent difference in the computational efficiency between the two models. Nevertheless, the CFD simulation required more effort in the pre-process for mesh generation. This problem was especially serious for simulating the heat exchangers with complex internals. In contrast, the LBM was a particle based method. It predicted the hydrodynamics by tracking the probability distribution function to an equilibrium state. The concept of discrete grids was replaced by the lattice. It only needed to specify the lattice size regardless of the geometrical adaption. Hence, the LBM modeling was considered to be more efficient and it was suggested highly for the simulation design of complex geometrical structures.
[1] Goldstein R J, Eckert E R G, Ibele W E, et al. Heat transfer — a review of 2000 literature [J]. Int. J. Heat Mass Transfer, 2002, 45(14): 2853-2957.
[2] Lei Y G, He Y L, Tian L T, et al. Hydrodynamics and heat transfer characteristics of a novel heat exchanger with delta-winglet vortex generators [J]. Chem. Eng. Sci., 2010, 65(5): 1551-1562.
[3] Li J, Cao W, Chen G. The heat transfer coefficient of new construction — Brick masonry with fly ash blocks [J]. Energy, 2015, 86: 240-246.
[4] Babu B V, Munawar S A. Differential evolution strategies for optimal design of shell?and?tube heat exchangers [J]. Chem. Eng. Sci., 2007, 62(14): 3720-3739.
[5] Chen G, Yang X, Lu Y, et al. Heat transfer intensification and scaling mitigation in bubbling-enhanced membrane distillation for brine concentration [J]. J. Membr. Sci., 2014, 470: 60-69.
[6] Khamis Mansour M, Fath H E. A new practical ε–NTU correlation for the humidification process under different Lewis number [J]. Desalination, 2016, 395: 72-78.
[7] Mathew B, Hegab H. Application of effectiveness -NTU relationship to parallel flow microchannel heat exchangers subjected to external heat transfer [J]. Int. J. Therm. Sci., 2010, 49(1): 76-85.
[8] Amin N A M, Belusko M, Bruno F. An effectiveness-NTU model of a packed bed PCM thermal storage system [J]. Appl. Energy, 2014, 134: 356-362.
[9] Colburn A P, Du Pont de E I. Mean temperature difference and heat transfer coefficient in liquid heat exchangers [J]. Ind. Eng. Chem., 1933, 25(8): 873-877.
[10] Cartaxo S J M, Fernandes F A N. Counterflow logarithmic mean temperature difference is actually the upper bound: A demonstration [J]. Appl. Therm. Eng., 2012, 55: 5931-5940.
[11] Tay N H S, Belusko M, Castell A, et al. An effectiveness-NTU technique for characterizing a finned tubes PCM system using a CFD model [J]. Appl. Energy, 2014, 131: 377-385.
[12] Tay N H S, Bruno F, Belusko M. Experimental validation of a CFD and an ε–NTU model for a large tube-in-tank PCM system [J]. Int. J. Heat Mass Transfer, 2011, 31: 1172-1175.
[13] Pal E, Kumar I, Joshi J B, et al. CFD simulations of shell-side flow in a shell?and?tube type heat exchanger with and without baffles [J]. Chem. Eng. Sci., 2016, 143: 314-340.
[14] Bellis F D, Catalano L A. CFD optimization of an immersed particle heat exchanger [J]. Appl. Energy, 2012, 97: 841-848.
[15] 张哲, 厉彦忠, 焦安军. 板翅式换热器封头结构的数值模拟 [J]. 化工学报, 2002, 53(11): 1311-1314.
[16] 张哲, 厉彦忠, 田津津. 板翅换热器导流片结构的数值模拟 [J]. 化工学报, 2002, 53(12): 1311-1314.
[17] Jayakumara J S, Mahajania S M, Mandal J C, et al. Experimental and CFD estimation of heat transfer in helically coiled heat exchangers [J]. Chem. Eng. Res. Des., 2008, 86(3): 221-232.
[18] Yataghene M, Legrand J. A 3D-CFD model thermal analysis within a scraped surface heat exchanger [J]. Comput. Fluids, 2013, 71: 380-399.
[19] Chen S, Doolen G D. Lattice Boltzmann method for fluid flows [J]. Annu. Rev. Fluid Mech., 1998, 30: 329-364.
[20] Zhang Y H, Gu X J, Barber R W, et al. Capturing Knudsen layer phenomena using a lattice Boltzmann model [J]. Phys. Rev. E, 2006, 74: 046704.
[21] Chen H, Chen S, Matthaeus W H. Recovery of the Navier?Stokes equations using a lattice-gas Boltzmann method [J]. Phys. Rev. A, 1992, 45(8): R5339-5342.
[22] Guo Z, Zheng C, Shi B. Discrete lattice effects on the forcing term in the lattice Boltzmann method [J]. Phys. Rev. E, 2002, 65: 046308.
[23] Lily D K. A proposed modification of the Germano subgrid-scale closure method [J]. Phys. Fluids, 1992, 4: 633-635.
[24] Paul S S, Tachie M F, Ormiston S J. Experimental study of turbulent cross-flow in a staggered tube bundle using particle image velocimetry [J]. Int. J. Heat Fluids Flow, 2007, 28(3): 441-453.
