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Precision droplet manufacturing: Component solidification, liquid metal droplet generation, and in-flight thermal control of droplet streams.

机译：精密的液滴制造：组件固化，液态金属液滴的产生以及液滴流的飞行中热控制。

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摘要

Precision Droplet Manufacturing (PDM) is a process that grows complex 3D parts one nano-liter molten metal droplet at a time from a CAD file without the need for tooling. This dissertation explores four varied but important PDM issues.; First, to address the challenges of jetting and generating droplets from molten aluminum, an improved metal droplet generator is designed, analyzed, built, and tested. The introduction of a remote, conical resonator improves molten metal droplet generation by increasing disturbance amplitude and stability. Vibration analysis guided and refined the design. Second, novel calibration and build schemes are detailed that improve process setup and efficiency.; Third, component integrity is explored by simulating the droplet splat solidification process. The 1D finite difference simulation uses an analytic start and allows for re-melting of previously deposited material. Transformations are used to transform the moving boundary problem to a fixed boundary problem. Re-melt depth as a function of process parameters is thoroughly investigated, and an analysis of realistic parameters for building with aluminum indicates successful inter-droplet splat bonding is feasible. Also, solidification rates verify PDM's classification as a rapid solidification process. In addition, multi-droplet simulations demonstrate that droplet splat stacking is sustainable, that is, it is possible for droplet splats to always solidify fully before the next droplet arrives.; Lastly, an in-flight convective droplet heater was designed and tested using helium and nitrogen as the convective agent and heating rates up to 11,000°C/s were attained. The effect of droplet spacing on heat transfer coefficient was experimentally detailed and an unexpected nascent-turbulent effect was observed. In addition, comparisons with previous multi-droplet numerical simulations were favorable.
机译：精密液滴制造（PDM）是一种无需使用工具即可从CAD文件一次将一个复杂的3D零件生长一个纳升熔融金属液滴的过程。本文探讨了四个不同但重要的PDM问题。首先，为了解决从熔融铝中喷射和产生液滴的挑战，设计，分析，构建和测试了一种改进的金属液滴发生器。远程圆锥形谐振器的引入通过增加干扰幅度和稳定性来改善熔融金属滴的产生。振动分析指导并完善了设计。其次，详细介绍了新颖的校准和构建方案，以改善过程设置和效率。第三，通过模拟液滴飞溅固化过程来探索部件的完整性。一维有限差分模拟使用解析起点，并允许重新熔化先前沉积的材料。转换用于将运动边界问题转换为固定边界问题。彻底研究了作为工艺参数的函数的重熔深度，对铝建筑实际参数的分析表明，成功的小滴间喷溅结合是可行的。同样，固化速率验证了PDM的分类是一种快速固化过程。另外，多液滴仿真表明，液滴飞溅的堆积是可持续的，也就是说，液滴飞溅可能始终在下一个液滴到达之前完全固化。最后，设计并使用氦气和氮气作为对流剂，对飞行中的对流液滴加热器进行了测试，并达到了11,000°C / s的加热速率。实验上详细描述了液滴间距对传热系数的影响，并观察到了意外的新生湍流效应。此外，与以前的多液滴数值模拟进行比较是有利的。

著录项

  • 作者

    Michaelis, Brian Matthew.;

  • 作者单位

    University of California, Irvine.;

  • 授予单位 University of California, Irvine.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 91 p.
  • 总页数 91
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

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