基于主动热Q开关的按需热功率放大
On-demand thermal power amplification enabled by active heat $Q$-switching
AI总结：
该研究提出主动热Q开关方法，利用逆流热振荡器实现按需热功率放大，实验获约5倍、数值预测约40倍峰值功率放大，为热功率管理提供新机制。
AI中文摘要：
热管理是从太阳能收集器、废热回收到工业过程加热和电子冷却等几乎所有能源技术的基础。然而，与电力和光学系统相比，热系统仍存在局限性：它们缺乏实现按需脉冲生成的主动控制元件的直接等效物。因此，在传统的热能存储架构中，存储的能量总量及其释放的峰值功率均由材料特性和热交换器几何形状在设计时固定，将每个设备锁定在能量-功率平面中的单一工作点。这种刚性与需要按需产生短时间、高功率热脉冲的应用不兼容。在此，我们证明逆流热振荡器具有可主动切换的有效热品质因数Q，并且在低于驻留时间的尺度上调制Q会产生超过稳态输入一个数量级以上的瞬态出口功率。我们将该系统形式化为耗散谐振热腔，其Q由平流、传导输运与环境损失之间的平衡控制，并且我们在水基双通道装置中通过受控流量失谐实验证明了约5倍的瞬态功率放大，与我们的热流体模型定量一致。主动Q开关确立了一种独特的热功率管理模式，通过单一架构在连续输入下实现约5倍（实验证明）至约40倍（数值预测）的峰值功率放大，这一机制是被动热存储无法实现的，也是光学和电子学中长期可用的主动脉冲生成工具的缺失等效物。
英文摘要：
Thermal management underpins essentially every energy technology, from solar harvesters and waste-heat recovery to industrial process heating and electronic cooling. Yet, thermal systems remain limited compared to their electrical and optical counterparts: they lack a direct equivalent of active control elements that enable on-demand pulse generation. As a result, in conventional thermal energy storage architectures, the amount of energy stored and the peak power at which it can be released are both fixed at design time by material properties and heat-exchanger geometry, locking each device to a single operating point in the energy--power plane. This rigidity is incompatible with applications that require short, high-power thermal bursts on demand. Here we show that a counter-flow heat oscillator admits an actively switchable effective thermal quality factor, $Q$, and that modulating $Q$ on sub-dwell-time scales generates transient outlet power exceeding the steady input by more than an order of magnitude. We formalize the system as a dissipative resonant thermal cavity with $Q$ controlled by the balance between advective and conductive transport and environmental losses, and we experimentally demonstrate, in a water-based dual-channel device, $\sim$5-fold transient power amplification through controlled flow detuning, in quantitative agreement with our thermofluidic model. Active $Q$-switching establishes a distinct mode of thermal power management, accessing $\sim$5$\times$ (demonstrated experimentally) to $\sim$40$\times$ (projected numerically) peak-power amplification on continuous input through a single architecture, a regime inaccessible to passive thermal storage and a missing analogue of the active pulse-generation tools long available in optics and electronics.
