带电波纹壁纳米通道中纳米流体的流向势与能量转化效率

The Streaming Potential and Energy Conversion Efficiency of Nanofluid in Charged Corrugated Wall Nanochannels

摘要: 本文通过理论建模与数值模拟，系统研究了正弦波纹壁面微通道中纳米流体的流动特性、流向势及能量转化效率。建立了综合考虑波纹几何参数(波幅δ、波数n、相位差θ)与纳米颗粒属性(体积分数φ)的电动力学流动模型，采用摄动法推导了电势、速度、流向势及能量转化效率的解析解，并利用切比雪夫谱方法获取了数值解并进行验证。研究结果表明：纳米流体的引入虽因有效粘度增加而降低了整体流速，但显著抑制了波谷区域的回流现象，增强了流动稳定性；当上下壁面波纹相位差θ = π时，通道横截面积均匀，中心处流速最大；对称管道中心流速、流向势及能量转化效率均存在极值，在临界波数nπ ≈ 0.1π和较大波幅时达到峰值，且当纳米粒子浓度增加时，能量转化效率提高。本研究揭示了波纹壁面与纳米颗粒的协同作用机制，为优化微流控系统中机械能–电能转化器件的设计提供了理论依据。

Abstract: This study systematically investigates the flow characteristics, flow direction potential, and energy conversion efficiency of nanofiuid in microchannels with sinusoidal corrugated walls through theoretical modeling and numerical simulation. An electrodynamics model was established, comprehensively considering the corrugation geometric parameters (amplitude δ, number of waves n, phase difference θ) and nanoparticle properties (volume fraction φ). The analytical solutions for potential, velocity, flow direction potential, and energy conversion efficiency were derived using the small parameter perturbation method, with numerical solutions validated via Chebyshev spectral analysis. Results demonstrate that while nanofluid introduction reduces overall flow velocity due to increased effective viscosity, it significantly suppresses backflow in the trough regions, enhancing flow stability. When the phase difference θ between upper and lower corrugations equals π, the channel cross-section becomes uniform with maximum velocity at the center. Symmetrical channels exhibit extremum values for central velocity, flow direction potential, and energy conversion efficiency, peaking at critical wave numbers nπ ≈ 0.1π and large amplitudes. Moreover, the energy conversion efficiency increases with increasing nanoparticle concentration. This research elucidates the synergistic mechanism between corrugated walls and nanoparticles, providing theoretical foundations for optimizing mechanical-to-electrical energy conversion devices in microfluidic systems.