文章快速检索 高级检索

Structure design of piezoelectric fans and research on influence of parameters
KONG Yue , LI Min , XIN Qingli
School of Aeronautic Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China
Received: 2015-09-02; Accepted: 2015-09-30; Published online: 2015-11-19
Corresponding author. Tel.:010-82338967,E-mail:limin@buaa.edu.cn
Abstract: A piezoelectric fan mainly consists of vibrating plate and actuator made by piezoelectric material. Vibrating plates are driven by actuators to cause fluid motion, which is a new kind of device for removal of heat. The purpose of this research is to investigate the influence of several parameters on the performance of piezoelectric fans and give advice to the design of piezoelectric fans. The method of computational fluid dynamics is used in this research to simulate the development of piezoelectric fan's flow field. Three parameters are studied including flexural modes of vibrating plates, double-plate orientation and phase difference between two plates. The results are as follows: the frequency of actuator should be equal to the fundamental resonance frequency of vibrating plate; for the models with two vibrating plates, the best phase difference is π (plates oriented in vertical direction) and 0.8π (plates oriented in horizontal direction). The cause of parameter influence is presented through analyzing the development of the flow field.
Key words: piezoelectric fan     wind velocity     numerical simulation     moving-grid     influence of parameters

1 计算模型与数据处理 1.1 计算模型

 图 1 压电风扇结构剖面 Fig. 1 Cross section of a piezoelectric fan

 图 2 标准模型计算域示意图 Fig. 2 Schematic of computational domain for standard model

 图 3 FLUENT中使用的网格示意图 Fig. 3 Schematic of grid used in FLUENT

1.2 数据处理

 图 4 流动时间与出口风速 Fig. 4 Wind velocity at outlet versus flow time

2 不同因素对出口风速的影响 2.1 高阶固有振型

 (1)

 (2)

 (3)

 图 5 不同振型下的出口风速与频率 Fig. 5 Wind velocity at outlet versus frequency for models with different flexural modes

2.2 双振动薄片纵向布置

 图 6 纵向布置双振动薄片模型结构示意图 Fig. 6 Schematic of model structure with two vibrating plates oriented in vertical direction

 图 7 纵向布置双振动薄片模型计算域示意图 Fig. 7 Schematic of computational domain for model with two vibrating plates oriented in vertical direction

 图 8 频率为50 Hz和100 Hz时相位差与出口风速(纵向布置) Fig. 8 Wind velocity at outlet versus phase difference for frequencies of 50 Hz and 100 Hz (plates oriented in vertical direction)

 图 9 3种模型出口风速比较(纵向布置) Fig. 9 Comparison of wind velocity at outlet among three models (plates oriented in vertical direction)

2.3 双振动薄片横向布置

 图 10 横向布置双振动薄片模型结构示意图 Fig. 10 Schematic of model structure with two vibrating plates oriented in horizontal direction

 图 11 横向布置双振动薄片模型计算域示意图 Fig. 11 Schematic of computational domain for model with two vibrating plates oriented in horizontal direction

 图 12 频率为50 Hz和100 Hz时相位差与出口风速(横向布置) Fig. 12 Wind velocity at outlet versus phase difference for frequencies of 50 Hz and 100 Hz (plates oriented in horizontal direction)

 图 13 3种模型出口风速比较(横向布置) Fig. 13 Comparison of wind velocity at outlet among three models (plates oriented in horizontal direction)
3 计算结果分析

 图 14 具有一阶固有振型的模型风速分布 Fig. 14 Wind velocity distribution for model with first order fundamental flexural modes

 图 15 具有一阶固有振型的模型压强分布 Fig. 15 Pressure distribution for model with first order fundamental flexural mode

3.1 高阶固有振型

 图 16 具有二阶固有振型的模型速度分布 Fig. 16 Velocity distribution for model with second order fundamental flexural mode

3.2 双振动薄片纵向布置

 图 17 流场速度分布比较(纵向布置) Fig. 17 Comparison of flow field velocity distribution(plates oriented in vertical direction)

 图 18 具有不同相位差的两种模型速度分布(纵向布置) Fig. 18 Velocity distribution for two models with different phase differences (plates oriented in vertical direction)

3.3 双振动薄片横向布置

 图 19 具有不同相位差的两种模型速度分布(横向布置) Fig. 19 Velocity distribution for two models with different phase differences (plates oriented in horizontal direction)
 图 20 具有不同相位差的两种模型压强分布(横向布置) Fig. 20 Pressure distribution for two models with different phase differences (plates oriented in horizontal direction)

4 结论

1) 驱动器的激振频率应等于振动薄片的一阶固有频率，即振动薄片应以其一阶固有振型振动。此时计算得到的出口风速远大于以高阶振型计算得到的出口风速。

2) 纵向布置双振动薄片模型，振动频率不变时，两振动薄片振动相位差为π时出口风速最大，相位差为0.3π或者1.7π时出口风速最小。最大出口风速与相同振动频率下的单振动薄片模型的出口风速相同。

3) 横向布置双振动薄片模型，振动频率不变时，两振动薄片振动相位差为0.8π时出口风速最大，相位差约为1.4π时出口风速最小。不论相位差取何值，横向布置双振动薄片模型的出口风速均大于相同振动频率下的单振动薄片模型的出口风速。

 [1] TODA M. Theory of air flow generation by a resonant type PVF2 bimorph cantilever vibrator[J]. Ferroelectrics, 1978, 22 (1) : 911 –918. DOI:10.1080/00150197908239445 [2] KIM Y H, WERELEY S T, CHUN C H. Phase-resolved flow field produced by a vibrating cantilever plate between two endplates[J]. Physics of Fluids (1994-present), 2003, 16 (1) : 145 –162. [3] KIMBER M, GARIMELLA S V, RAMAN A. Local heat transfer coefficients induced by piezoelectrically actuated vibrating cantilevers[J]. Journal of Heat Transfer, 2007, 129 (9) : 1168 –1176. DOI:10.1115/1.2740655 [4] KIMBER M,GARIMELLA S V,RAMAN A.An experimental study of fluidic coupling between multiple piezoelectric fans[C]//10th Intersociety Conference on Thermal and Thermomechanical Phenomena and Emerging Technologies in Electronic Systems,ITherm 2006.Piscataway,NJ:IEEE Press,2006:333-340. [5] YOO J H, HONG J I, CAO W. Piezoelectric ceramic bimorph coupled to thin metal plate as cooling fan for electronic devices[J]. Sensors and Actuators A:Physical, 2000, 79 (1) : 8 –12. DOI:10.1016/S0924-4247(99)00249-6 [6] WU T, RO P I. Heat transfer performance of a cooling system using vibrating piezoelectric beams[J]. Journal of Micromechanics and Microengineering, 2005, 15 (1) : 213 –220. DOI:10.1088/0960-1317/15/1/030 [7] FLORIO L A, HARNOY A. Combination technique for improving natural convection cooling in electronics[J]. International Journal of Thermal Sciences, 2007, 46 (1) : 76 –92. DOI:10.1016/j.ijthermalsci.2006.03.007 [8] AÇIKALIN T, GARIMELLA S V, RAMAN A, et al. Characterization and optimization of the thermal performance of miniature piezoelectric fans[J]. International Journal of Heat and Fluid Flow, 2007, 28 (4) : 806 –820. DOI:10.1016/j.ijheatfluidflow.2006.10.003 [9] AÇIKALIN T, WAIT S M, GARIMELLA S V, et al. Experimental investigation of the thermal performance of piezoelectric fans[J]. Heat Transfer Engineering, 2004, 25 (1) : 4 –14. DOI:10.1080/01457630490248223 [10] SCHMIDT R R.Local and average transfer coefficients on a vertical surface due to convection from a piezoelectric fan[C]//Proceedings of the Intersociety Conference on Thermal Phenomena in Electronic Systems.Piscataway,NJ:IEEE Press,1994:41-49. [11] 贾丽杰, 李敏, 陈伟民. 压电驱动器应变传递模型分析[J]. 工程力学, 2010, 27 (8) : 205 –210. JIA L J, LI M, CHEN W M. The model analysis of strain transfer in the application of piezoelectric actuators[J]. Engineering Mechanics, 2010, 27 (8) : 205 –210. (in Chinese) [12] QURESHI E M, SHEN X, CHEN J J. Vibration control laws via shunted piezoelectric transducers:A review[J]. International Journal of Aeronautical and Space Sciences, 2014, 15 (1) : 1 –19. DOI:10.5139/IJASS.2014.15.1.1 [13] 朱熹育, 王社良, 朱军强. 基于Sugeno型模糊神经网络的空间杆系结构的压电驱动器主动控制[J]. 工程力学, 2013, 30 (8) : 272 –277. ZHU X Y, WANG S L, ZHU J Q. Sugeno-type fuzzy neural network active control of space frame structure based on piezoelectric actuator[J]. Engineering Mechanics, 2013, 30 (8) : 272 –277. (in Chinese) [14] 谭蕾, 谭晓茗, 张靖周. 压电风扇激励非定常流动和换热特性数值研究[J]. 航空学报, 2013, 34 (6) : 1277 –1284. TAN L, TAN X M, ZHANG J Z. Numerical investigation on unsteady flow and heat transfer characteristics of piezoelectric fan[J]. Acta Aeronautica et Astronautica Sinica, 2013, 34 (6) : 1277 –1284. (in Chinese) [15] 孔岳, 李敏, 吴蒙蒙. 压电风扇非定常流场速度分布的数值研究[J]. 工程力学, 2016, 33 (1) : 209 –216. KONG Y, LI M, WU M M. Numerical investigation on the velocity of unsteady flow field induced by piezoelectric fan[J]. Engineering Mechanics, 2016, 33 (1) : 209 –216. (in Chinese) [16] HU H, CLEMONS L, IGARASHI H. An experimental study of the unsteady vortex structures in the wake of a root-fixed flapping wing[J]. Experiments in Fluids, 2011, 51 (2) : 347 –359. DOI:10.1007/s00348-011-1052-z [17] 刑誉峰, 李敏. 工程振动基础[M]. 2版.北京: 北京航空航天大学出版社, 2011 : 136 -144. XING Y F, LI M. Engineering vibration[M]. 2nd ed.Beijing: Beihang University Press, 2011 : 136 -144. (in Chinese)

#### 文章信息

KONG Yue, LI Min, XIN Qingli

Structure design of piezoelectric fans and research on influence of parameters

Journal of Beijing University of Aeronautics and Astronsutics, 2016, 42(9): 1977-1985
http://dx.doi.org/10.13700/j.bh.1001-5965.2015.0567