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Forced Convection Heat Transfer Characteristics of Slush Nitrogen in Turbulent Pipe Flows

湍流管流中氮泥强制对流换热特性

基本信息

批准号：
18360096
负责人：
OHIRA Katsuhide
金额：
$ 5.97万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18360096/
关键词：
Cryogenic Fluid Forced Convection Heat Transfer Two-phase Solid-liquid Flow Slush Nitrogen Slush Hydrogen Renewable Energy Reusable Space Shuttle Superconducting Equipment 水素

项目摘要

Slush Fluids, such as slush hydrogen and slush nitrogen, are two-phase (solid-liquid) single-component cryogenic fluids containing solid particles in a liquid. The objectives of the present study are to investigate the forced convection heat transfer characteristic and thermo-fluid instability of slush nitrogen flowing in a pipe, and to develop the numerical code to evaluate the thermo-fluid phenomenon of the slush fluid flowing in a pipe.Experimental tests were performed with the slush nitrogen in the ranges of solid fraction from 0 to 40 wt% and mean velocity from 1 to 6m/s to obtain both the forced convection heat transfer coefficient and the frictional pressure drop flowing in a horizontal copper pipe. Compared with the experimental results of subcooled liquid nitrogen, the deterioration phenomena of heat transfer coefficients for slush nitrogen caused by the pressure drop reduction were found and cleared in the present study. This is the important and useful result for applying the slush fluid as a refrigerant to superconducting equipments.Three-dimensional numerical simulation method including the gravity effect based on the two-fluid model has been developed to clarify the characteristics of the cryogenic two-phase slush fluid in a straight pipe flow. It was found that the calculated results were in good agreement with the velocity distributions of solid particles measured by the new PIV (Particle Image Velocimetry) method. In consequence, the developed numerical code has been verified to be able to calculate the slush flow characteristics with sufficient accuracy.

雪泥流体，例如雪泥氢和雪泥氮，是在液体中含有固体颗粒的两相（固液）单组分低温流体。本研究的目的是研究泥浆氮气在管道中流动的强制对流换热特性和热流体不稳定性，并开发数值代码来评估管道中泥浆流体的热流体现象。在固体分数为 0 至 40 wt%、平均速度为 1 至 1 的范围内对泥浆氮气进行了实验测试。 6m/s以获得强制对流换热系数和在水平铜管中流动的摩擦压降。与过冷液氮的实验结果相比，本研究发现并清除了因压降降低而引起的泥浆氮传热系数恶化的现象。这是将雪泥流体作为制冷剂应用于超导设备的重要而有用的结果。基于二流体模型，建立了包括重力效应的三维数值模拟方法，以阐明直管流中低温两相雪泥流体的特性。结果发现，计算结果与新的PIV（粒子图像测速）方法测量的固体颗粒速度分布吻合良好。因此，所开发的数字代码已被验证能够以足够的精度计算泥浆流动特性。