Study on enhanced heat transfer of power-law fluids in microchannels using flexible vortex generators and tandem cylinders
-
摘要:
利用壁挂式柔性涡流发生器（FVG）、串列圆柱和非牛顿流体增强微通道的传热，采用任意拉格朗日-欧拉（ALE）格式的有限元法，对描述微通道中流固耦合的连续性方程、动量方程和能量方程进行求解。在双圆柱间距离固定的条件下，调整FVGs与圆柱之间的间距以及改变流体的幂律指数（
n ），研究对称壁挂式FVGs通道中幂律流体的流致振动现象及换热性能。与直微通道相比，当下游圆柱与柔性板间距离G x =1.5、幂律指数n =1.2时，努塞尔数Nu 增加了184%，热性能系数增加了45%。Abstract:A wall-mounted flexible vortex generator (FVG), a tandem column, and a non-Newtonian fluid were utilized to enhance the heat transfer in a microchannel. The finite element method in arbitrary Lagrangian-Eulerian (ALE) format was used to solve the continuity, momentum, and energy equations describing the flow-solid coupling in microchannels. The flow-induced vibration behavior and heat transfer performance of a power-law fluid in a symmetric wall-mounted FVGs channel were investigated by adjusting the spacing between the FVGs and the columns, and varying the power-law exponent (
n ) of the fluid under the condition of a fixed distance between the two columns. When the distance between the downstream column and the flexible plateG x =1.5 and the power-law indexn =1.2, Nusselt numberNu increased by 184% and the thermal performance coefficient increased by 45% compared with the straight microchannel. -
图 1 双圆柱诱导对称壁挂式FVGs结构示意图
Figure 1. Schematic structure of double columns induced symmetric wall-mounted FVGs
图 3 对称壁挂式FVGs上板的Xtip运动历程（20 s≤t≤ 20.2 s）
Figure 3. Motion history of Xtip of the upper plate in the symmetric wall-mounted FVGs （20 s≤t≤20.2 s）
图 5 二维参数空间（Gx, n）上两个对称壁挂式FVGs的4种不同摆动模式的区域划分图
Figure 5. Regional division of two symmetric wall-mounted FVGs with four different oscillation modes on a two-dimensional parameter space （Gx, n）
图 6 不同模式下的上下板的尾端横向位移、纵向位移的时间历程以及尾端横向位移的功率谱
Figure 6. Time histories of the transverse displacement and longitudinal displacement of the tail end of the upper and lower plates and the power spectra of the tail end in different modes
图 7 （Gx, n）=（2.0,1.0）时尾端横向位移Ytip和纵向位移Xtip的时间历程以及Ytip的频谱Pf
Figure 7. Time histories of the transverse displacement （Ytip） and longitudinal displacement （Xtip） of the tail end and the power spectra of the tail end Ytip （Pf） for （Gx, n）=（2.0,1.0）
图 8 O模式下对称壁挂式FVGs周围4个时刻下的涡量场
Figure 8. Vorticity fields around symmetric wall-mounted FVGs at four moments in O mode
图 9 O模式下对称壁挂式FVGs周围4个时刻下的温度云图
Figure 9. Temperature clouds around symmetric wall-mounted FVGs at four moments in O mode
图 10 O模式下上下壁面的（Ⅰ～Ⅳ）时刻瞬时努塞尔数（Nu）
Figure 10. Instantaneous Nusselt number （Nu） at （I—Ⅳ） moments for the upper and lower walls in O mode
图 11 20.00 s≤t≤20.50 s时间内几种典型案例下平均Nu（$ \overline{Nu} $）的空间变化
Figure 11. Spatial variation of mean Nu （$ \overline{Nu} $） for several typical cases at time 20.00 s≤t≤20.50 s
图 12 带双圆柱的对称FVGs系统整体努塞尔数Nuavg 和阻力系数$ {C}_{\rm{f}} $在（Gx, n）区域内的等高线图
Figure 12. Contour plots of the overall Nusselt number Nuavg and total flow resistance coefficient $ {C}_{\rm{f}} $ of the symmetric FVGs with double columns in the （Gx, n） region
图 13 相较于牛顿流体和相较于直微通道的带双圆柱的对称FVGs的热效率在（Gx, n）区域内的等高线图
Figure 13. Contour plots of the thermal efficiency of the symmetric FVGs with double columns compared to the Newtonian fluid and compared to the straight microchannel in the （Gx, n） region
图 14 对称FVGs、直微通道及带双圆柱的对称FVGs的整体努塞尔数Nuavg、阻力系数$ {C}_{\rm{f}} $和性能评价标准Pec,cm随幂律指数（n）的变化
Figure 14. Overall Nusselt number Nuavg, total flow resistance coefficient $ {C}_{\rm{f}} $, and performance evaluation criteria Pec,cm as a function of the power-law exponent （n） for the symmetric FVGs, straight microchannel, and symmetric FVGs with double columns
-
[1] KHATTAK Z, ALI H M. Air cooled heat sink geometries subjected to forced flow: a critical review[J]. International Journal of Heat and Mass Transfer, 2019, 130: 141-161. doi: 10.1016/j.ijheatmasstransfer.2018.08.048 [2] SOLEYMANI Z, RAHIMI M, GORZIN M, et al. Performance analysis of hotspot using geometrical and operational parameters of a microchannel pin-fin hybrid heat sink[J]. International Journal of Heat and Mass Transfer, 2020, 159: 120141. doi: 10.1016/j.ijheatmasstransfer.2020.120141 [3] ZHAO Xiaohuan, SU Limin, JIANG Jiang, et al. A review of working fluids and flow state effects on thermal performance of micro-channel oscillating heat pipe for aerospace heat dissipation[J]. Aerospace, 2023, 10(2): 179. doi: 10.3390/aerospace10020179 [4] BUNONYO K W, EBIWAREME L. Oscillatory blood flow and embolitic plaque effect through a microchannel with metabolic heat and magnetic field[J]. European Journal of Applied Physics, 2022, 4(1): 35-51. doi: 10.24018/ejphysics.2022.4.1.147 [5] HAAS S, ASMUSSEN N. A trusted communication unit for secure tiled hardware architectures[C]//2022 29th IEEE International Conference on Electronics, Circuits and Systems. Piscataway, US: IEEE, 2022: 1-4. [6] HAJIALIBABAEI M, SAGHIR M Z. A critical review of the straight and wavy microchannel heat sink and the application in lithium-ion battery thermal management[J]. International Journal of Thermofluids, 2022, 14: 100153. doi: 10.1016/j.ijft.2022.100153 [7] WANG Jiansheng, WANG Xin, LIU Xueling. Numerical investigation on flow behavior and heat transfer feature of flexible wings located at the bottom of a two-dimensional channel[J]. Applied Thermal Engineering, 2022, 206: 118112. doi: 10.1016/j.applthermaleng.2022.118112 [8] O’CONNOR J, REVELL A. Dynamic interactions of multiple wall-mounted flexible flaps[J]. Journal of Fluid Mechanics, 2019, 870: 189-216. doi: 10.1017/jfm.2019.266 [9] LEE J B, PARK S G, SUNG H J. Heat transfer enhancement by asymmetrically clamped flexible flags in a channel flow[J]. International Journal of Heat and Mass Transfer, 2018, 116: 1003-1015. doi: 10.1016/j.ijheatmasstransfer.2017.09.094 [10] DADVAND A, HOSSEINI S, AGHEBATANDISH S, et al. Enhancement of heat and mass transfer in a microchannel via passive oscillation of a flexible vortex generator[J]. Chemical Engineering Science, 2019, 207: 556-580. doi: 10.1016/j.ces.2019.06.045 [11] HOSSEINI S, AGHEBATANDISH S, DADVAND A, et al. An immersed boundary-lattice Boltzmann method with multi relaxation time for solving flow-induced vibrations of an elastic vortex generator and its effect on heat transfer and mixing[J]. Chemical Engineering Journal, 2021, 405: 126652. doi: 10.1016/j.cej.2020.126652 [12] JEONG Y D, AHN K H, KIM M J, et al. Heat transfer enhancement in a channel flow using two wall-mounted flexible flags with a confined cylinder[J]. International Journal of Heat and Mass Transfer, 2022, 195: 123185. doi: 10.1016/j.ijheatmasstransfer.2022.123185 [13] COTTA R M, ÖZI§IK M N. Laminar forced convection of power-law non-Newtonian fluids inside ducts[J]. Wärme-und Stoffüber-tragung, 1986, 20(3): 211-218. [14] LU D C, FAROOQ U, HAYAT T, et al. Computational analysis of three layer fluid model including a nanomaterial layer[J]. International Journal of Heat and Mass Transfer, 2018, 122: 222-228. doi: 10.1016/j.ijheatmasstransfer.2018.01.080 [15] HALMOS A L, BOGER D V, CABELLI A. The behavior of a power-law fluid flowing through a sudden expansion: Part I a numerical solution[J]. AIChE Journal, 1975, 21(3): 540-549. doi: 10.1002/aic.690210316 [16] MIRZAEI NEJAD M, JAVAHERDEH K. Numerical simulation of power-law fluids flow and heat transfer in a parallel-plate channel with transverse rectangular cavities[J]. Case Studies in Thermal Engineering, 2014, 3: 68-78. doi: 10.1016/j.csite.2014.03.004 [17] RASHIDI M M, BAGHERI S, MOMONIAT E, et al. Entropy analysis of convective MHD flow of third grade non-Newtonian fluid over a stretching sheet[J]. Ain Shams Engineering Journal, 2017, 8(1): 77-85. doi: 10.1016/j.asej.2015.08.012 [18] BHATTI M M, ABBAS T, RASHIDI M M. Numerical study of entropy generation with nonlinear thermal radiation on magnetohydrodynamics non-Newtonian nanofluid through a porous shrinking sheet[J]. Journal of Magnetics, 2016, 21(3): 468-475. doi: 10.4283/JMAG.2016.21.3.468 [19] TRIPATHI A M, GHOSH S K, SARKAR S. Two dimensional unsteady flow past a square cylinder: influence of proximal plane wall and power-law index[J]. Ocean Engineering, 2021, 240: 109896. doi: 10.1016/j.oceaneng.2021.109896 [20] BAO Yan, ZHOU Dai, TU Jiahuang. Flow interference between a stationary cylinder and an elastically mounted cylinder arranged in proximity[J]. Journal of Fluids and Structures, 2011, 27(8): 1425-1446. doi: 10.1016/j.jfluidstructs.2011.08.008 [21] BAO Yan, HUANG Cheng, ZHOU Dai, et al. Two-degree-of-freedom flow-induced vibrations on isolated and tandem cylinders with varying natural frequency ratios[J]. Journal of Fluids and Structures, 2012, 35: 50-75. doi: 10.1016/j.jfluidstructs.2012.08.002 [22] CELIK B, RAISEE M, BESKOK A. Heat transfer enhancement in a slot channel via a transversely oscillating adiabatic circular cylinder[J]. International Journal of Heat and Mass Transfer, 2010, 53(4): 626-634. doi: 10.1016/j.ijheatmasstransfer.2009.10.034 -
下载:
点击查看大图
计量
- 文章访问数: 522
- HTML浏览量: 284
- PDF量: 45
- 被引次数: 0