基于压电风扇位移的周期性运动规律,采用动网格技术对存在横流时双压电风扇激励的三维非定常流动和传热进行数值模拟,获得了双压电风扇两种布置方式(并列和串列)在同相和反相振动方式下的涡系结构和表面换热特征。研究结果表明,双压电风扇振动相位对于对流换热性能有较大的影响,对于并列布置的双压电风扇,反相振动时在双风扇振动包络区下游的换热能力优于同相振动情形;对于串列布置的双压电风扇,反相振动时在相邻风扇之间的区域对流换热显著低于同相振动情形。
A numerical investigation is performed to explore the 3D unsteady flow features and heat transfer performance induced by dual vertically-oriented piezoelectric fans in the presence of cross flow. The numerical simulations are conducted by using dynamic meshing scheme in combination with the periodic movement law of the displacement of the vibrating fan. The vortical and thermal features with dual piezoelectric fans are obtained for two dual fans arrangements (face-to-face and edge-to-edge) at in-phase and out-of-phase vibrating conditions. The results show that the vibrating phase of dual fans has an obvious influence on convective heat transfer performance. For the dual fans arranged in the face-to-face mode, the convective heat transfer downstream the fan-tip vibration envelope under the out-of-phase situation is higher than that under the in-phase situation. For the dual fans arranged in the edge-to-edge mode, the convective heat transfer in the region between two adjacent fans under the out-of-phase situation is significantly less than that under the in-phase situation.
[1] YOO J H, HONG J I, CAO W. Piezoelectric ceramic bimorph coupled to thin metal plate as cooling fan for electronic devices[J]. Sensors Actuators A, 2000, 79(1):8-12.[2] CHUNG H C, KUMMARI K L, CROUCHER S J, et al. Development of piezoelectric fans for flapping wing application[J]. Sensors and Actuators A:Physical, 2009, 149(1):136-142.[3] GILSON G M, PICKERING S J, HANN D B, et al. Piezoelectric fan cooling:A novel high reliability electric machine thermal management solution[J]. IEEE Transactions on Industrial Electronics, 2013, 60(11):4841-4851.[4] KIM Y H, WERELEY S T, CHUN C H. Phase-resolved flow field produced by a vibrating cantilever plate between two endplates[J]. Physics in Fluids, 2004, 16(1):145-162.[5] KIM Y H, CHUN C H, WERELEY S. Flow field around a vibrating cantilever:Coherent structure education by continuous wavelet transform and proper orthogonal decomposition[J]. Journal of Fluid Mechanics, 2011, 669:584-606.[6] KIMBER M, SUZUKI K, KITSUNAI N, et al. Pressure and flow rate performance of piezoelectric fans[J]. IEEE Transactions on Components and Packaging Technologies, 2009, 32(4):766-775.[7] 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).[8] TAN L, ZHANG J Z, TAN X M. Numerical investigation of convective heat transfer on a vertical surface due to resonating cantilever beam[J]. International Journal of Thermal Sciences, 2014, 80:93-107.[9] 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).[10] ACIKALIN 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.[11] ACIKALIN 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.[12] ACIKALIN T, GARIMELLA S V. Analysis and prediction of the thermal performance of piezoelectrically actuated fans[J]. Heat Transfer Engineer, 2009, 30(6):487-498.[13] KIMBER M, GARIMELLA S V, RAMAN A. Local heat transfer coefficients induced by piezoelectrically actuated vibrating cantilevers[J]. ASME Journal of Heat Transfer, 2007, 129(9):1168-1176.[14] KIMBER M, GARIMELLA S V. Measurement and prediction of the cooling characteristics of a generalized vibrating piezoelectric fan[J]. International Journal of Heat and Mass Transfer, 2009, 52(19-20):4470-4478.[15] LIU S F, HUANG R T, SHEU W J, et al. Heat transfer by a piezoelectric fan on a flat surface subject to the influence of horizontal/vertical arrangement[J]. International Journal of Heat and Mass Transfer, 2009, 52(11-12):2565-2570.[16] LIN C N. Analysis of three-dimensional heat and flow induced by piezoelectric fan[J]. International Journal of Heat and Mass Transfer, 2012, 55(11-12):3043-3053.[17] LIN C N. Enhanced heat transfer performance of cylindrical surface by piezoelectric fan under forced convection conditions[J]. International Journal of Heat and Mass Transfer, 2013, 60:296-308.[18] JENG T M, LIU C H. Moving-orientation and position effects of the piezoelectric fan on thermal characteristics of the heat sink partially filled in a channel with axial flow[J]. International Journal of Heat and Mass Transfer, 2015, 85:950-964.[19] 李鑫郡, 张靖周, 谭晓茗. 单个压电风扇传热特性研究[J]. 航空学报, 2017, 38(7):120982. LI X J, ZHANG J Z, TAN X M. Characteristics of heat transfer with a single piezoelectric fan[J]. Acta Aeronautica et Astronautica Sinica, 2017, 38(7):120982(in Chinese).[20] JEONG J, HUSSAIN F. On the definition of a vortex[J]. Journal of Fluid Mechanics, 1995, 285:69-94.