單液滴於減速運動對空氣污染物吸收之數值探討

Numerical Simulation on Air Pollutant Uptake by a Single Droplet with Deceleration

陳維新(Wei-Hsin Chen) ； 劉昭忠(Chao-Chung Liu)

《中國航空太空學會學刊》 37卷2期 (2005/06) Pp. 163-169

https://doi.org/10.6124/TAASRC.200506_37(2).07

摘要

本研究利用數值方法模擬大氣中單氣膠水滴吸收氯化氫之行爲，其中初始雷諾數取10及100二種情形，氣膠運動並考慮拖曳力作用，即減速運動對吸收過程之效應，並比較減速作用對質量傳輸現象的影響。結果顯示，氣膠的減速過程比吸收過程爲快，故減速行爲明顯降低吸收速率。而氣膠內部造成之渦流作用，引起質量傳輸以對流方式由氣膠表面沿流線傳向氣膠中心，而後再以擴散方式往渦流中心傳輸。吸收初期氣膠內部質量與動量傳輸變化極大，後來趨於平緩。本研究除對大氣氣膠吸收現象之瞭解有所幫助外，對於日後空污防治設備如吸收塔及噴霧塔之設計也可提供參考。

關鍵字

氯膠 ； 吸收 ； 氯化氫 ； 拖曳力

並列摘要

Hydrogen chloride uptake by a water aerosol is simulated in the present study. Two different initial Reynolds numbers of 10 and 100 are taken into consideration. Of particular attention is placed on the effect of drag force upon the uptake process. The results reveal that the variation of aerosol velocity is faster than that of the absorption process, rendering the droplet uptake rate being substantially decreased by the deceleration motion. Regarding the mass transfer, the simulations suggest that the solute is transported along the streamlines from the aerosol surface to the droplet center via convection. Then it moves toward the vortex core through diffusion. In the initial period the mass and momentum transfers are violently, but they decay progressively with time. The obtained results not only provide a fundamental insight into the recognition of atmospheric aerosol absorption, they also give a useful reference for designing wet scrubbers and spray towers in the future.

並列關鍵字

Aerosol ； Absorption ； Hydrogen chloride ； Drag force