Engineering Research Equipment Grant: A Deterministic Analysis of Turbulent Mass Transfer (Spectrum Analyzer)

该项目是一项工程研究设备补助金。项目描述：对气液界面附近获得的速度波动数据进行确定性分析，可以估计参与气体吸收的单个旋涡的长度和速度尺度。结果表明，在两种湍流气体吸收过程中，用该方法预测的传质效果优于采用均方根速度和积分长度尺度的统计方法。提出了一种将确定性方法推广到更高的湍流和不同的器件几何形状。预计频谱分析仪将极大地扩展本研究的范围。利用氧气微探头和激光多谱勒风速仪同时测量浓度和速度波动，首次能够在单个涡流水平上研究传递现象。利用该方法对所提出的分析传质现象的确定性方法进行了验证。论证：建议的研究将有助于建立分析速度波动数据的确定性方法，以获得单个涡旋的长度和速度尺度。与传统的统计方法相比，这一新方法有望更好地预测传质过程，并可推广到传热学领域。在设计新型生物发酵器和气液化学反应器方面具有潜在的应用前景。

This project is an Engineering Research Equipment Grant. PROJECT DESCRIPTION: Deterministic analyses applied to velocity fluctuation data obtained close to gas-liquid interface allow the estimation of the length and velocity scales of individual eddies taking part in gas absorption. The mass transfer prediction by this method has been shown to be superior to that by the statistical method employing the root mean square velocity and the integral length scale in two turbulence gas absorption. An extension of the deterministic approach to higher turbulence and for different device geometries is proposed. The spectrum analyzer is expected to expand the scope in this research significantly. Simultaneous measurements of concentration and velocity fluctuations by an oxygen microprobe and a laser doppler anemometer allow, for the first time, the investigation of transfer phenomena on a single eddy level. This method is utilized to confirm the proposed deterministic approach for analyzing mass transfer phenomena. JUSTIFICATION: The proposed research will help establish the deterministic method for analyzing the velocity fluctuation data to obtain the length and velocity scales of individual eddies. This new approach is expected to give better prediction of the mass transfer compared with the conventional statistical approach, and it could be extended to heat transfer as well. Potential applications exist in design of new biofermentors and gas-liquid chemical reactors.