【摘要】：在工業(yè)生產(chǎn)中,經(jīng)常出現(xiàn)某種工藝流程在不同的反應(yīng)階段物料粘度變化范圍很寬的情況,傳統(tǒng)高粘度流體混合攪拌槳,如螺帶式槳、錨式槳、最大葉片式槳,在過(guò)渡域及湍流域內(nèi)的混合效率較低；而湍流域常用攪拌槳,如直葉槳、斜葉槳、渦輪槳等在高粘度流體中作用區(qū)范圍有限,無(wú)法達(dá)到全槽循環(huán)流動(dòng)。目前,多層較大槳徑的開(kāi)式槳組合操作方式被提出應(yīng)用于上述工況。本文以FCC催化劑生產(chǎn)工藝為背景,采用較大槳徑的三葉后掠式槳與CBY槳的組合槳攪拌型式,對(duì)不同參數(shù)的三葉后掠槳及其與CBY槳組合操作的功率及混合特性進(jìn)行實(shí)驗(yàn)研究和數(shù)值模擬。實(shí)驗(yàn)采用內(nèi)徑為476 mm的橢圓封頭攪拌槽,選取不同粘度的糖漿水溶液作為模擬物料,液位H/T=1.0。改變?nèi)~后掠式槳的葉輪直徑D,‘曲率半徑廠(chǎng),葉根角θ,葉片寬度w等參數(shù),研究幾何參數(shù)改變對(duì)三葉后掠式槳及組合槳攪拌功率及混合特性的影響；此外利用CFX數(shù)值模擬軟件,對(duì)層流域及湍流域內(nèi),不同幾何參數(shù)的三葉后掠槳流型、速度分布及不同直徑三葉后掠槳的作用范圍進(jìn)行研究。實(shí)驗(yàn)結(jié)果表明：層流域內(nèi),D/T=0.7的三葉后掠式槳沿徑向的作用范圍可以達(dá)到槽壁,軸向作用范圍可達(dá)H有效/D=0.8；三葉后掠槳的曲率半徑和葉輪寬度的增加,均會(huì)使攪拌槳的功率準(zhǔn)數(shù)增加,而葉根角的增大使得功率準(zhǔn)數(shù)減�。煌ㄟ^(guò)功率及混合性能測(cè)試,葉根角為200的三葉后掠式槳混合效率最高。推薦采用三葉后掠式槳(D/T=0.7, r/D=0.333,θ=20°)與CBYW槳的雙層組合槳形式應(yīng)用于FCC催化劑生產(chǎn)等類(lèi)似工業(yè)過(guò)程生產(chǎn)中。利用CFX軟件進(jìn)行的數(shù)值模擬發(fā)現(xiàn)：對(duì)于層流域的流場(chǎng)而言,單層三葉后掠攪拌槳沿徑向的作用范圍約為1.4倍的攪拌槳直徑。層流域內(nèi),D/T小于0.7時(shí),在槽壁附近將存在流動(dòng)死區(qū)。另外,增加三葉后掠槳的曲率半徑r對(duì)流場(chǎng)的影響不大,但葉根角的增大,可以提高三葉后掠攪拌槳的軸向循環(huán)能力,較高速流體(V0.2VTS)區(qū)域的軸向高度可增加10%。
[Abstract]:In industrial production, there is often a situation in which the viscosity of materials varies widely in different reaction stages. Traditional high viscosity fluid mixing propellers, such as propellers, anchor propellers, maximum vane propellers, are often used in industrial production. The mixing efficiency in transition region and turbulent basin is low. However, in the turbulent domain, the impeller, such as the straight blade propeller, the oblique blade propeller, the turbine impeller and so on, have a limited range of action zones in the high viscosity fluid, so they can not reach the circulating flow in the whole tank. At present, the open propeller combined operation mode with multi-layer and large diameter has been proposed to be applied to the above working conditions. In this paper, based on the production process of FCC catalyst, the combined propeller type with large impeller diameter is adopted, which is composed of three blade backswept propeller and CBY propeller. The experimental study and numerical simulation of the power and mixing characteristics of the three-leaf swept back propeller with different parameters and its combined operation with CBY propeller are carried out. In the experiment, an elliptical head stirring tank with an inner diameter of 476 mm was used, and syrup aqueous solution with different viscosity was selected as the simulation material, and the liquid level was 1.0. The influence of geometric parameters on the stirring power and mixing characteristics of the three-leaf swept impeller and combined impeller was studied by changing the parameters such as the diameter of the impeller D 'curvature radius factory, the angle 胃 of the blade root and the width w of the blade. In addition, the flow pattern, velocity distribution and the action range of trifoliate impeller with different geometric parameters in the layer basin and turbulent region are studied by using CFX software. The experimental results show that the radial range of D/T=0.7 three-leaf swept propeller can reach the groove wall, and the axial action range can reach H effective / D0. 8; The increase of the radius of curvature and the width of impeller will increase the power number of the impeller, but the increase of the blade root angle will decrease the power criterion. According to the test of power and mixing performance, the mixing efficiency is the highest when the blade root angle is 200. It is recommended that the double-layer combined propeller with CBYW propeller (D / T _ (0.7), r / D _ (0.333), 胃 = 20 擄) should be used in the production of FCC catalyst and other similar industrial processes. The numerical simulation with CFX software shows that for the flow field of the watershed, the radial action range of the single-layer three-leaf swept impeller is about 1.4 times of the diameter of the impeller. When D / T is less than 0.7, there will be a dead zone near the trough wall. In addition, increasing the curvature radius r of the impeller has little effect on the flow field, but the axial circulation ability of the impeller can be improved by increasing the blade root angle, and the axial height of the impeller can be increased by 10% than that of the high speed fluid (V0.2VTS) region.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TQ027.2

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 吳雨唐;基于普魯蘭多糖發(fā)酵的攪拌槳參數(shù)優(yōu)化及攪拌性能分析[D];西南大學(xué);2017年

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本文編號(hào)：2384347