Abstract Heat transfer characteristics of water flow boiling in a minichannel were investigated through the direct measurement of local heat flux using a fabricated MEMS heat flux sensor with a multi-layered structure. Local temperatures and heat fluxes in the water flow boiling were measured at a sampling frequency of 10 kHz in synchronism with the high-speed visualization of the boiling behavior. The measurement results revealed fundamental heat transfer processes, including thin liquid film evaporation, dry-out of the liquid film, transient heat conduction after dry patch rewetting, and single-phase forced convection. The thin liquid film evaporation indicated a high local heat flux that was well over 1 MW/m2 and provided a dominant contribution to the wall heat transfer. Furthermore, the post-rewetting transient heat conduction indicated a high heat flux that was higher than 1 MW/m2. However, it was insignificant in terms of the overall wall heat transfer at all the tested heat fluxes because of its short duration. The contribution of liquid-phase forced convection was also small, except at low vapor qualities.

中文翻译：

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使用 MEMS 热通量传感器直接测量矩形微通道中水流沸腾过程中的局部热通量

摘要 通过使用多层结构的MEMS热流传感器直接测量局部热流，研究了微通道中水流沸腾的传热特性。以 10 kHz 的采样频率与沸腾行为的高速可视化同步测量水流沸腾中的局部温度和热通量。测量结果揭示了基本的传热过程，包括薄液膜蒸发、液膜干燥、干片再润湿后的瞬态热传导和单相强制对流。薄液膜蒸发表明远高于 1 MW/m2 的高局部热通量，并为壁传热提供了主要贡献。此外，再润湿后的瞬态热传导表明高热通量高于 1 MW/m2。然而，由于其持续时间较短，因此在所有测试热通量下的整体壁面传热方面微不足道。除了低蒸气质量外，液相强制对流的贡献也很小。