Expedited Award for Novel Research: Deterministic Chaos in Nucleate Boiling

这项研究的目的是确定是否脱离的 饱和核态沸腾中的气泡从一个单一的位置 从周期性到混沌， #21415;，以寻找合适的低？ 现象的三维模型。 一项关于 电加热圆柱形腔将被执行， 确定周期。 从孤立的气泡到 将绘制连续的蒸气柱。 一种基于 分叉和动力系统理论将得到发展。 有许多机制是负责热 从沸腾表面转移到饱和液体。 对这些过程的理论研究认识到 的因素，如气泡频率，成核点密度和 气泡直径 它们都依赖于热通量，表面 和腔体尺寸的方式，不完全是 明白 本提案的结果将有助于 通过确定频率来理解部分现象 蒸汽气泡离开成核位置， 随着热流量的变化而发生质变和量变。 将 可以找出是否统计分布的 气泡离开频率是由于确定性混沌。 因此 实验也将是至关重要的评估低- 三维模型，以模拟在一定范围内的热量的过程 剂.

The goal of this research is to determine if the detachment of bubbles in saturated nucleate boiling from a single site goes from periodic to chaotic through a reproducible sequence of bifurcations, with the purpose of searching for a suitable low- dimensional model of the phenomenon. An experimental study of an electrically heated cylindrical cavity will be performed to determine the periodicity. The route from isolated bubbles to continuous vapor columns will be mapped. A model based upon bifurcations and dynamical systems theory will be developed. There are many mechanisms which are responsible for the heat transfer from a boiling surface to a saturated liquid. Theoretical studies of these processes recognize the importance of factors such as bubble frequency, nucleation site density and bubble diameter. They all depend on the heat flux, surface superheat and cavity size in ways that are not entirely understood. The results of the present proposal will help in understanding part of the phenomenon by determining the frequency with which vapor bubbles leave a nucleation site as well as its qualitative and quantitative change with heat flux. It will be possible to find out whether the statistical distribution of bubble departure frequencies is due to deterministic chaos. Thus the experiments will also be vital in evaluating a low- dimensional model to simulate the process over a range of heat fluxes.