Abstract Noisy film boiling in nearly saturated He II caused by heating from a flat plate heater placed horizontally was investigated by applying visualization method and PIV (Particle Image Velocimetry) using hydrogen-deuterium solid particles as tracer particles. The images taken by a high-speed video to be used for the PIV were also used for visualization study, and the appearance of generation, growth and collapse processes of mass of tiny bubbles caused due to boiling and the qualitative aspect of the flow field could be understood. By the application of the PIV technique, the frequency of growth and collapse of bubble mass and the flow velocity field formed in the surrounding He II were measured. The output from the PIV was further examined separately for the time average and the time fluctuating components, and in each, independent flow components were identified. It was shown that the steady flow components include the plume above the heater and the entrainment towards the plume as well as the thermal counterflow. And the standing radially alternating flow is induced by repeatedly growing and collapsing bubble mass as a fluctuating flow. Their superposition forms the surrounding flow field.

中文翻译：

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饱和 He II 中嘈杂薄膜沸腾过程中流场的 PIV 测量

摘要 应用可视化方法和以氢-氘固体颗粒作为示踪剂颗粒的PIV（粒子图像测速法）研究了由水平放置的平板加热器加热引起的近饱和He II 中的噪声薄膜沸腾。用于PIV的高速视频拍摄的图像也用于可视化研究，沸腾引起的大量微小气泡的产生、生长和崩溃过程的出现和流场的定性方面可以被理解。通过PIV技术的应用，测量了气泡质量的增长和崩溃的频率以及在周围He II中形成的流速场。PIV 的输出分别针对时间平均值和时间波动分量进行了进一步检查，并且在每个分量中，确定了独立的流动成分。结果表明，稳定流分量包括加热器上方的羽流和朝向羽流的夹带以及热逆流。静止的径向交替流是由气泡质量作为波动流反复生长和坍塌引起的。它们的叠加形成了周围的流场。