计算机与应用化学
計算機與應用化學
계산궤여응용화학
COMPUTERS AND APPLIED CHEMISTRY
2013年
7期
703-708
,共6页
张敏华%王召亚%李永辉%耿中峰
張敏華%王召亞%李永輝%耿中峰
장민화%왕소아%리영휘%경중봉
SAS(超临界抗溶剂法)%结晶釜%直径%CFD%喷嘴
SAS(超臨界抗溶劑法)%結晶釜%直徑%CFD%噴嘴
SAS(초림계항용제법)%결정부%직경%CFD%분취
SAS%precipitator%diameter%CFD%nozzle
为探讨结晶釜直径对 SAS(超临界抗溶剂法)过程的影响规律，并确定适宜的结晶釜直径，本文采用计算流体力学(CFD)方法，选用Realizable k-ε湍动模型对SAS喷射过程建立模型。结晶釜高度为L=190 mm，考察了直径分别为40 mm、30 mm、20 mm和15 mm时釜内流体迹线、溶剂浓度分布、有效扩散因子分布及湍动强度分布变化规律，尤其是喷嘴出口附近溶液射流区内的流场变化状况。结果表明，随着结晶釜直径的减小，釜内漩涡区逐渐向釜顶缩小，有利于避免釜内颗粒间碰撞造成的粘结；釜内溶剂浓度逐渐减小，而有效扩散因子分布及湍动强度的绝对值逐渐增大但分布范围逐渐向釜顶缩小；喷嘴出口附近溶液射流区内的有效扩散因子与湍动强度逐渐增大，有利于提高成核速率而减小颗粒粒径。较小直径的结晶釜，还会降低流体在釜内的停留时间，减少颗粒生长时间而利于减小颗粒粒径，因此选择小直径结晶釜对SAS过程有利。本文通过CFD模拟研究，揭示了SAS结晶釜直径对SAS成粒过程的影响规律，对SAS结晶釜的优化设计具有一定的理论指导。
為探討結晶釜直徑對 SAS(超臨界抗溶劑法)過程的影響規律，併確定適宜的結晶釜直徑，本文採用計算流體力學(CFD)方法，選用Realizable k-ε湍動模型對SAS噴射過程建立模型。結晶釜高度為L=190 mm，攷察瞭直徑分彆為40 mm、30 mm、20 mm和15 mm時釜內流體跡線、溶劑濃度分佈、有效擴散因子分佈及湍動彊度分佈變化規律，尤其是噴嘴齣口附近溶液射流區內的流場變化狀況。結果錶明，隨著結晶釜直徑的減小，釜內漩渦區逐漸嚮釜頂縮小，有利于避免釜內顆粒間踫撞造成的粘結；釜內溶劑濃度逐漸減小，而有效擴散因子分佈及湍動彊度的絕對值逐漸增大但分佈範圍逐漸嚮釜頂縮小；噴嘴齣口附近溶液射流區內的有效擴散因子與湍動彊度逐漸增大，有利于提高成覈速率而減小顆粒粒徑。較小直徑的結晶釜，還會降低流體在釜內的停留時間，減少顆粒生長時間而利于減小顆粒粒徑，因此選擇小直徑結晶釜對SAS過程有利。本文通過CFD模擬研究，揭示瞭SAS結晶釜直徑對SAS成粒過程的影響規律，對SAS結晶釜的優化設計具有一定的理論指導。
위탐토결정부직경대 SAS(초림계항용제법)과정적영향규률，병학정괄의적결정부직경，본문채용계산류체역학(CFD)방법，선용Realizable k-ε단동모형대SAS분사과정건립모형。결정부고도위L=190 mm，고찰료직경분별위40 mm、30 mm、20 mm화15 mm시부내류체적선、용제농도분포、유효확산인자분포급단동강도분포변화규률，우기시분취출구부근용액사류구내적류장변화상황。결과표명，수착결정부직경적감소，부내선와구축점향부정축소，유리우피면부내과립간팽당조성적점결；부내용제농도축점감소，이유효확산인자분포급단동강도적절대치축점증대단분포범위축점향부정축소；분취출구부근용액사류구내적유효확산인자여단동강도축점증대，유리우제고성핵속솔이감소과립립경。교소직경적결정부，환회강저류체재부내적정류시간，감소과립생장시간이리우감소과립립경，인차선택소직경결정부대SAS과정유리。본문통과CFD모의연구，게시료SAS결정부직경대SAS성립과정적영향규률，대SAS결정부적우화설계구유일정적이론지도。
A Computer fluid dynamic (CFD) model was established using the Realizable k-εturbulent model herein in order to investigate the precipitator’s diameter effects on the particle sizes and morphology in the Supercritical antisolvent (SAS) process and determine the optimum diameter of the precipitator. The CFD model was used to study the influence of the SAS precipitators diameter of 40 mm, 30 mm, 20 mm and 15 mm on the fluid pathline, DMSO mole fraction distribution, Def distribution, and turbulent intensity distribution. These influences near the nozzle were studied especially. It can be concluded that the swirl shrinked towards the top of the precipitator, which helped avoid agglutinating among the particles due to the collision;the concentration of the solvent reduced, and the Def and I increased but with less scope when the precipitator diameter decreased;the Def and I increased in the solution jet near the nozzle exit, which was benefited to reduce the particle size as it helped to speed up the nucleation rate. In addition, precipitators with smaller diameter shortened the residual time of the fluid, and therefore reduced the particle growth time resulting in obtaining smaller particles. The CFD results explained the precipitator’s diameter effects on the SAS process. This paper remarkably provided insight into the mechanisms that govern the particle sizes in the SAS process.
