Effect of Initial Inclination Angle of Elastic Pillars on Heat Transfer Enhancement in Microchannel

doi:10.12068/j.issn.1005-3026.2025.20230264

Abstract

Abstract:

To solve the heat dissipation problem of electronic devices， the flow and heat transfer features of elastic pillar with different initial inclinations in microchannel are numerically investigated. Furthermore， the influences of dynamic characteristics and inclination angle of the elastic pillar on fluid heat transfer performance， hydrodynamic friction factor， and overall hydrothermal efficiency are probed. The results indicate that 1.25 μm oscillation is generated when the inclination angle of the elastic pillar is 0.2π. This small amplitude is not conducive to the generation of vortices. On the other hand， an elastic pillar in a fully flapping mode can generate periodic vortices， which is more conducive to the disturbance to the boundary layer and the mixing of cold and hot fluids， thereby enhancing heat transfer. In the range of Re from 800 to 1 200， the elastic pillar has the optimal inclination angle of 0.6π. Under the optimum working condition， at the expense of high mechanical loss， the heat transfer performance of the fluid can be improved by 63.5%， and the total hydrothermal efficiency can be increased by 7.5%.

Key words: heat transfer enhancement, flexible vortex generator, microchannel, arbitrary Lagrangian-Eulerian （ALE） method, numerical simulation

CLC Number:

TK 124

Ke-fan YU, Liang ZHAO, Hui DONG, Yong-qing HE. Effect of Initial Inclination Angle of Elastic Pillars on Heat Transfer Enhancement in Microchannel[J]. Journal of Northeastern University(Natural Science), 2025, 46(2): 42-49.

Figures/Tables 18

Fig.1 Geometric schematic diagram of two-dimensional microchannels

Table 1 Geometric parameters for two-dimensional microchannels

参数	数值	参数	数值
微通道宽度H/μm	35w	圆柱障碍物离壁面B的距离b/μm	17.5w
微通道长度L/μm	150w	圆柱障碍物直径d/μm	3w
柔性柱离流动入口的距离l/μm	42w	柔性柱宽度w/μm	14
圆柱障碍物离流动入口的距离c/μm	11w	柔性柱高度h/μm	13w
柔性柱倾角θ	0.2π ~ 0.8π

Table 2 Physical properties of elastic pillar material

物性参数	数值	物性参数	数值
密度/（kg·m^-3）	2 500	泊松比	0.48
弹性模量/MPa	7	导热系数/（W·m^-1·K^-1）	2.5
比热容/（J·kg^-1·K^-1）	1 200

Fig.2 Physical model diagram proposed by Turek et al [25]（unit：mm）

Fig.3 Displacement of flexible pillar tip

Fig.4 Comparison between present work and simulation results by Dadvand et al [15]

Fig.5 Mesh division of elastic pillar microchannels with an inclination angle of 0.5π

Table 3 Verification of grid independence for elastic pillar with an inclination angle of 0.5π

网格数	Nu_tot	误差/%	计算时间/h
579 59	33.199	12.3	8.65
103 348	33.441	11.7	22.47
128 000	37.555	0.8	34.43
148 102	37.867	0.0	48.98

Fig.6 Transient velocity cloud and streamline diagrams of microchannels with different inclination angles of elastic pillar

Fig.7 Transient vorticity cloud pictures of microchannels with different inclination angles of elastic pillar

Fig.8 Tip displacement of the x-component at the end of an elastic pillar with different inclination angles

Fig.9 Frequency of the x-component at the end of an elastic pillar with different inclination angles

Fig.10 The total Nusselt number of the walls on both sides of microchannel under different inclination angles of elastic pillar

Fig.11 The total Nusselt number ratio and friction coefficient ratio of microchannels under different inclination angles of elastic pillar

Fig.12 Comprehensive performance of microchannels under different inclination angles of elastic pillar

Fig.13 von Mises stress diagram of an elastic pillar with an inclination angle of 0.6π （Re=1 000）

Fig.14 Maximum von Mises stress of elastic pillar with different inclination angles

Fig.15 Maximum von Mises stress at point E of an elastic pillar with an inclination angle of 0.8 π under different Re

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