A Computational Examination of the Sources of Statistical Variance in Particle Parameters During Thermal Plasma Spraying
A Computational Examination of the Sources of Statistical Variance in Particle Parameters During Thermal Plasma Spraying
复制标题
热等离子喷涂过程中颗粒参数统计方差来源的计算检验
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
C.
中科院分区：
文献类型：
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作者：
R. L. Williamson;J. Fincke;C.
计算模型用于系统地检查热等离子喷涂过程中颗粒参数统计方差的许多来源。首先使用计算机程序 LAVA 开发出一种在正常操作条件下典型的商用火炬的稳态等离子射流。然后，假设单一颗粒成分 (ZrO2) 和注射位置，引入现实世界的复杂性（例如，湍流分散、颗粒尺寸和密度、注射速度和方向）“一次一种现象”，以区分和表征其效果并能够比较单独的效果。还进行计算，其中同时考虑所有现象以实现进一步的比较。非旋流和旋流等离子体流场都被考虑。单独研究每种现象可以提供对颗粒行为的有价值的见解。对于所考虑的典型等离子体射流和喷射条件，喷射方向上的颗粒分散最显着地受到以下因素的影响（按照重要性递减的顺序）：颗粒尺寸分布、喷射速度分布、湍流和喷射方向分布或颗粒密度分布。在本研究中，只有喷射方向和湍流的分布影响垂直于喷射方向的分散，并且对于颗粒速度和温度而言，颗粒尺寸显然是主要影响。
Computational modeling is used to systematically examine many of the sources of statistical variance in particle parameters during thermal plasma spraying. Using the computer program LAVA, a steady-state plasma jet typical of a commercial torch at normal operating conditions, is first developed. Then, assuming a single particle composition(ZrO2) and injection location, real world complexity (e.g., turbulent dispersion, particle size and density, injection velocity, and direction) is introduced ``one phenomenon at a time” to distinguish and characterize its effect and enable comparisons of separate effects. Calculations are also performed wherein all phenomena are considered simultaneously to enable further comparisons. Both nonswirling and swirling plasma flow fields are considered. Investigating each phenomenon separately provides valuable insight into particle behavior. For the typical plasma jet and injection conditions considered, particle dispersion in the injection direction is mostsignificantly affected by (in order of decreasing importance): particle size distribution, injection velocity distribution, turbulence, and injection direction distribution or particle density distribution. Only the distribution of injection directions and turbulence affect dispersion normal to the injection direction and are of similar magnitude in this study. With regards to particle velocity and temperature, particle size is clearly the dominant effect.