The World's First Test Facility That Enables the Experimental Visualization of Cavitation on a Rotating Inducer in Both Cryogenic and Ordinary Fluids
The World's First Test Facility That Enables the Experimental Visualization of Cavitation on a Rotating Inducer in Both Cryogenic and Ordinary Fluids
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世界上第一个能够在低温和普通流体中对旋转诱导器上的空化进行实验可视化的测试设施
DOI：
10.1115/1.4051849
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Yu Ito
中科院分区：
文献类型：
--
作者：
大谷清伸;小川俊広;中川敦寛;阿部淳;Yu Ito
众所周知，涡轮分子泵中会发生空化击穿，即泵扬程随着入口空化数的减少而突然下降的现象。特别是在低温泵中，与水等普通流体相比，在入口空化数较低的情况下会发生空化破坏。正如斯蒂芬诺夫报道的那样，这种现象被称为热力学效应。工作流体的热力学性质影响空化单元的尺寸，从而影响空化的击穿；因此，实验流动可视化是实现更高效、更可靠的低温泵的有效方法。 2010 年，作者和同事开发了世界上第一个测试设备，能够实现低温和普通流体中旋转诱导轮上空化的可视化。当时，关于旋转低温叶轮的流动可视化只发表了两篇报告：一篇是 1967 年 NASA 发表的液氢流动可视化报告，另一篇是日本宇宙航空研究开发机构 (JAXA) 2010 年发表的液氮流动可视化报告。目前的设备采用直径为 65.3 毫米、转速高达 8000 rpm 的三螺纹螺旋诱导轮，可同时处理液氮和水。可作为工作流体。通过对液氮和水中诱导体空化的非定常可视化实验，通过对表现出更强热力学效应的低温流体与水等普通流体的比较，揭示了尖端涡空化、回流涡空化和空化单元尺寸的特征。
It is well known that cavitation breakdown, which is a phenomenon in which the pump head suddenly drops with a decrease in the inlet cavitation number, occurs in turbopumps. Especially in cryogenic pumps, cavitation breakdown occurs at a lower inlet cavitation number than that of ordinary fluids such as water. This phenomenon is referred to as a thermodynamic effect, as Stepanoff reported. The thermodynamic properties of the working fluid affect the sizes of the cavitation elements, which affect cavitation breakdown; therefore, experimental flow visualization is an effective approach to realize a more efficient and more reliable cryogenic pump. In 2010, the author and colleagues developed the world's first test facility to enable the visualization of cavitation on a rotating inducer in both cryogenic and ordinary fluids. At that time, only two reports on the flow visualization of a rotating cryogenic impeller had been published: one on flow visualization in liquid hydrogen by NASA in 1967 and the other on flow visualization in liquid nitrogen by the Japan Aerospace Exploration Agency (JAXA) in 2010. The present facility employs a triple-thread helical inducer with a diameter of 65.3 mm and a rotation rate of up to 8000 rpm, with both liquid nitrogen and water available as working fluids. Unsteady visualization experiments for cavitation on an inducer in liquid nitrogen and water have revealed the characteristics of tip vortex cavitation, backflow vortex cavitation, and cavitation element size based on comparisons between cryogenic fluids that exhibit a stronger thermodynamic effect and ordinary fluids such as water.