本文選題：旋流器　切入點(diǎn)：分選下限　出處：《煤炭科學(xué)研究總院》2017年碩士論文

【摘要】：本文旨在從重介質(zhì)旋流器內(nèi)部顆粒受力運(yùn)動(dòng)的角度探索懸浮液粘度與旋流器分選下限之間的關(guān)系問題。在前人對(duì)旋流器內(nèi)部速度場(chǎng)研究的基礎(chǔ)上,用數(shù)值模擬的流體力學(xué)方法,得到流場(chǎng)數(shù)據(jù);并結(jié)合回歸分析的數(shù)學(xué)方法對(duì)數(shù)據(jù)進(jìn)行擬合處理,得到結(jié)構(gòu)參數(shù)確定的旋流器內(nèi)部流場(chǎng)的具體數(shù)學(xué)公式。在前人對(duì)固液兩相流研究的基礎(chǔ)上,認(rèn)為雖然固相顆粒受力眾多,但是在旋流器中真正需要考慮的只有5個(gè)力:離心力、浮力、流體阻力、虛擬質(zhì)量力、Basset力。結(jié)合擬合得到的速度場(chǎng)公式和受力分析,提出了旋流器內(nèi)部顆粒運(yùn)動(dòng)的理論:顆粒在入料口處存在"初始命運(yùn)"的差異;旋流器分選的主要任務(wù)是讓"初始命運(yùn)"在外旋流中的煤顆粒在離開底流口之前穿越LZVV,讓"初始命運(yùn)"在內(nèi)旋流的矸石顆粒在進(jìn)入溢流管之前穿越LZVV;分選下限顆粒,以煤顆粒為例,最終將經(jīng)過LZVV與底流口的交界線,且各有50%的機(jī)會(huì)進(jìn)入內(nèi)、外旋流。在不同粘度下得到的Fluent數(shù)值模擬結(jié)果中分別進(jìn)行同密度差不同粒度的顆粒追蹤,得到不同粘度下的分選下限。從而得到粘度與分選下限的關(guān)系。這個(gè)關(guān)系與忽略虛擬質(zhì)量力的情況下半定量分析的結(jié)果相同:懸浮液的動(dòng)力粘度增大n倍,旋流器的分選下限增大√n倍。運(yùn)用流場(chǎng)擬合的結(jié)果與顆粒在旋流器中的運(yùn)動(dòng)理論來(lái)直接計(jì)算分選下限,發(fā)現(xiàn)在忽略虛擬質(zhì)量力的情況下,計(jì)算得出的分選下限與Fluent數(shù)值模擬得出的分選下限相差近3倍;在不忽略虛擬質(zhì)量力的情況下,由于方程過于復(fù)雜,沒能得出解,原因在于擬合得到的軸向速度和徑向速度的數(shù)量表達(dá)式過于復(fù)雜。
[Abstract]:The purpose of this paper is to explore the relationship between suspension viscosity and the lower separation limit of hydrocyclone from the point of view of the force motion of particles in the heavy medium cyclone. Based on the previous researches on the internal velocity field of the hydrocyclone, the hydrodynamic method of numerical simulation is used. The flow field data are obtained, and the data are fitted with regression analysis, and the specific mathematical formula of flow field in hydrocyclone determined by structural parameters is obtained. On the basis of previous researches on solid-liquid two-phase flow, It is considered that although the solid particles have a large number of forces, only five forces should be considered in the hydrocyclone: centrifugal force, buoyancy force, fluid resistance, virtual mass force and Basset force, combined with the fitted velocity field formula and force analysis. The theory of particle movement in the hydrocyclone is put forward: the difference of "initial fate" between the particles at the inlet; The main task of cyclone separation is to allow coal particles in the "initial fate" outer swirl to pass through LZVV before leaving the bottom flow port, and to allow the gangue particles in the "initial fate" inner swirl to pass through the LZVV before entering the overflow pipe. Taking coal particles as an example, the particles will eventually pass through the junction of LZVV and the bottom flow, and each of them will have 50% chance to enter the inner and outer swirls. The numerical simulation results of Fluent obtained under different viscosity will be followed by the particles with the same density difference and different particle size, respectively. The relationship between the viscosity and the separation limit is obtained. This relationship is the same as that of the semi-quantitative analysis under the condition of ignoring the virtual mass force: the dynamic viscosity of the suspension increases by n times, The separation lower limit of hydrocyclone is increased by n times. The separation lower limit is directly calculated by using the flow field fitting result and the motion theory of particles in the cyclone. It is found that the virtual mass force is ignored. The difference between the calculated separation limit and that obtained by Fluent numerical simulation is nearly three times. Without neglecting the virtual mass force, the equation is too complicated to be solved. The reason is that the quantitative expressions of axial velocity and radial velocity are too complicated.
【學(xué)位授予單位】：煤炭科學(xué)研究總院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TD94

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