Two-phase systems comprising of a single pump or compressor, a condenser, and multiple microchannel evaporators can provide the unique advantage of handling multiple heat sources while being compact and lightweight. Such systems also present challenges with regards to handling asynchronous transient heat loads, maintaining fixed evaporator temperatures, enabling high system efficiencies, and avoiding the critical heat flux. The overall objective of this study is to dynamically control the performance of a two-phase system comprising of two evaporators experiencing transient heat loads. This study simulates a pumped liquid cycle comprising of two microchannel evaporators using the moving boundary model, which considers phase-change heat transfer and pressure drop occurring in the evaporators. The moving boundary model predicts the overall performance corresponding to different system settings and evaporator heat loads to determine the optimum operating conditions. By knowing these conditions in advance, the study presents a strategy combining feedforward and feedback control to ensure system operation close to the optimum operating condition. The approach discussed in this study is generally applicable and allows maintaining the desired evaporator temperatures and high system efficiency in the presence of transient heat loads.

由一个泵或一个压缩机，一个冷凝器和多个微通道蒸发器组成的两相系统可以提供独特的优势，既可以处理多个热源，又可以使其结构紧凑，重量轻。这样的系统在处理异步瞬态热负荷，保持固定的蒸发器温度，实现高系统效率以及避免临界热通量方面也提出了挑战。这项研究的总体目标是动态控制两相系统的性能，该系统由两个承受瞬时热负荷的蒸发器组成。这项研究使用移动边界模型模拟了由两个微通道蒸发器组成的泵送液体循环，该模型考虑了蒸发器中发生的相变传热和压降。移动边界模型预测与不同系统设置和蒸发器热负荷相对应的总体性能，以确定最佳运行条件。通过事先了解这些条件，该研究提出了一种将前馈和反馈控制相结合的策略，以确保系统操作接近最佳操作条件。本研究中讨论的方法通常适用，并可以在存在瞬态热负荷的情况下保持所需的蒸发器温度和高系统效率。