本文選題：高黏度流體 + 組合槳��； 參考：《北京化工大學》2015年碩士論文

【摘要】：本文利用計算流體力學(CFD)數(shù)值模擬方法,在直徑為0.476 m的攪拌槽內(nèi),以高黏度牛頓流體為研究體系,對直段槳為雙螺帶式和Paravisc式以及底槳為錨式和變徑螺帶式的一系列組合槳功率和混合時間進行了研究,并對其中的優(yōu)選槳型進行了放大規(guī)律探索。通過對數(shù)值模擬結(jié)果的分析發(fā)現(xiàn),雙螺帶式槳、Paravisc式和錨式槳功率均隨槳葉寬度增加而增加,且螺距對于雙螺帶式槳的功率影響更加顯著。根據(jù)模擬結(jié)果,擬合得到了四類組合槳中組合槳的Kp關(guān)聯(lián)式,這對于高黏度流體組合槳的設(shè)計提供了重要參考。對各組合槳混合特性的研究發(fā)現(xiàn),絕對混合時間的確定會因示蹤劑監(jiān)測點位置不同而有所差異,但是各組合槳的混合特性卻表現(xiàn)出一致的規(guī)律：以錨式槳為底槳的各組合槳的混合時間均小于以變徑螺帶式槳為底槳的組合槳混合時間,其中Paravisc-錨式組合槳達到完全混合時的絕對混合時間最小,所轉(zhuǎn)圈數(shù)最少,較圈數(shù)最多的雙螺帶-3號變徑螺帶式槳少將近三分之一；此外,該組合槳的單位體積耗能也最低,無量綱剪切量隨轉(zhuǎn)速變化斜率最大,各種混合效果評定方法均表明Paravisc-錨式組合槳混合特性優(yōu)于本文中其他組合槳。最后將體積為100 L的攪拌槽放大至200 L和500 L的攪拌槽,選用Paravisc-錨式組合槳,在模擬物料保持一致的情況下,組合槳功率曲線在不同尺度下完全一致,并于三個尺度的最佳轉(zhuǎn)速下進行模擬發(fā)現(xiàn)其符合槳端線速度的放大準則。本文對各槳型的功率特性、混合特性和放大規(guī)律的分析,可為工業(yè)設(shè)計和優(yōu)化高黏度流體組合槳參數(shù)提供重要參考。
[Abstract]:In this paper, the numerical simulation method of computational fluid dynamics (CFD) is used to study the high viscosity Newtonian fluid in a stirred tank with a diameter of 0.476 m. The power and mixing time of a series of combined propellers with straight propeller being double screw belt type and Paravisc type and bottom propeller with anchor type and variable diameter screw belt type are studied. Through the analysis of the numerical simulation results, it is found that both the power of the double screw belt propeller Paravisc and the anchor propeller increase with the blade width, and the pitch has a more significant effect on the power of the double screw belt propeller. According to the simulation results, the KP correlation of four kinds of combined propellers is obtained, which provides an important reference for the design of high viscosity fluid composite propellers. It is found that the determination of absolute mixing time varies with the location of tracer monitoring points. However, the mixing characteristics of the combined propellers show the same regularity: the mixing time of the combined propellers with anchor propellers as the bottom propeller is shorter than that with the variable diameter propeller as the bottom propeller. The absolute mixing time of Paravis c- anchor combined propeller is the smallest and the number of cycles is the least, which is nearly 1/3 less than that of the double screw belt-3 variable diameter propeller with the largest number of cycles. In addition, the combined propeller has the lowest energy consumption per unit volume. The slope of dimensionless shear varies with rotational speed is the largest, and all kinds of mixed effect evaluation methods show that the mixing characteristic of Paravisc- anchor combined propeller is better than that of other combined propellers in this paper. Finally, the volume of 100L agitator is enlarged to 200L and 500L agitator, and Paravisc- anchor type combined propeller is selected. The power curve of the combined propeller is completely consistent at different scales under the condition that the simulated material remains the same. At the optimal speed of three scales, it is found that the model accords with the magnification criterion of linear velocity at the end of the propeller. In this paper, the power characteristics, mixing characteristics and amplifying rules of each propeller type are analyzed, which can provide important reference for industrial design and optimization of the parameters of high viscosity fluid combination propeller.
【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ027

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本文編號：1901799