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首页> 外文会议>HTD-vol.376-2; ASME(American Society of Mechanical Engineers) International Mechanical Engineering Congress and Exposition; 20051105-11; Orlando,FL(US) >CRYOGENIC TWO-PHASE FLOW AND HEAT TRANSFER UNDER TERRESTRIAL AND MICROGRAVITY
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CRYOGENIC TWO-PHASE FLOW AND HEAT TRANSFER UNDER TERRESTRIAL AND MICROGRAVITY

机译：地面和微重力作用下的深冷两相流和热传递

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摘要

This paper presents experimental investigations of cryogenic nitrogen two-phase flow in horizontal transparent tubes (diameters of 11.1 mm) under terrestrial and micro-gravity (10~(-4)g) conditions during the chilldown process, and the focus is on the film boiling region. Constant mass flow rate is achieved by a motor driven bellows, and three different mass fluxes from 9.2 to 21.6 kg/m~2·s are tested in the experiments. A drop tower is applied to simulate the micro-gravity environment. During the chilldown process, we measure the time-dependent temperatures at three circumferential locations at different downstream locations. Video images are recorded for identifying the flow patterns. The experiments show that under normal gravity, the flow pattern change from dispersed flow to inverted annular flow and then to unsteady stratified flow according to different wall temperatures, the temperature differences between the lower and upper part of the test section increase with increasing flow rate. Under microgravity, when the temperature is high, the liquid chunks trend to be lifted up and confined mainly in the central core of the tube; when the temperature is low, the liquid chunks are more evenly dispersed inside the whole tube, and some touch the upper wall. It is also found that the measured wall temperatures drop more quickly under microgravity condition compared with that under normal gravity. Moreover, under microgravity condition, the measured temperatures drop more quickly with lower wall temperature. The gravity effect on the quenching curves is alleviated with increasing mass flow rate. Thus gravity effect is more important in low mass flow rate two-phase flow.
机译：本文介绍了冷却过程中地面和微重力（10〜（-4）g）条件下水平透明管（直径为11.1 mm）中低温氮气两相流的实验研究，重点是薄膜。沸腾的区域。通过电动机驱动的波纹管实现恒定的质量流量，并在实验中测试了从9.2到21.6 kg / m〜2·s的三种不同质量通量。应用了一个吊塔来模拟微重力环境。在冷却过程中，我们在不同下游位置的三个圆周位置测量随时间变化的温度。记录视频图像以识别流型。实验表明，在正常重力作用下，随着壁温的变化，流型从分散流变为倒环形流，然后变为非稳态分层流，试验段下部和上部之间的温差随流速的增加而增大。在微重力作用下，当温度高时，液体块趋向于上升并被限制在管的中心。当温度低时，液体块更均匀地分散在整个管子内部，并且有一些接触上壁。还发现，与正常重力下相比，在微重力条件下测得的壁温下降得更快。此外，在微重力条件下，随着壁温降低，测得的温度下降得更快。随着质量流量的增加，重力对淬火曲线的影响得以缓解。因此，重力效应在低质量流量的两相流中更为重要。

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