旋風(fēng)分離器內(nèi)置渦核破碎翼的實(shí)驗(yàn)及數(shù)值研究
發(fā)布時(shí)間：2018-11-08 21:16
【摘要】：旋風(fēng)分離器作為典型的氣固分離設(shè)備,工作機(jī)理主要依賴(lài)氣流與其攜帶的塵粒之間存在密度差,導(dǎo)致兩者一旦進(jìn)入旋風(fēng)分離器,作螺旋向下運(yùn)動(dòng)的同時(shí),形成能使顆粒脫離氣流主體運(yùn)動(dòng)從而被分離的速度滑移。早期的旋風(fēng)分離器僅在工業(yè)領(lǐng)域應(yīng)用比較廣泛；而今隨著旋風(fēng)分離器逐年發(fā)展,該設(shè)備的性能不斷得到優(yōu)化,加之造價(jià)、運(yùn)行成本低廉、可操作環(huán)境范圍廣,愈發(fā)得到全世界各個(gè)行業(yè)的重視。目前,微型旋風(fēng)分離也被逐漸推廣至空氣凈化、食品分離、生物、醫(yī)藥等精密行業(yè)。為更進(jìn)一步優(yōu)化旋風(fēng)分離器的性能,人們對(duì)該設(shè)備的認(rèn)知能力從簡(jiǎn)單的性能定性分析發(fā)展到流場(chǎng)特性的定量分析。然而,旋風(fēng)分離器內(nèi)相流變化規(guī)律反常,很多學(xué)者在對(duì)各種旋風(fēng)分離器模型進(jìn)行優(yōu)化以獲得較高效率的同時(shí),不得不考慮壓降增大的負(fù)面影響。本課題針對(duì)旋風(fēng)分離器效率中等、壓降較高的特點(diǎn),試圖改善旋風(fēng)分離器性能使其向“保效減阻”的終極目標(biāo)進(jìn)發(fā),提出一種能使旋風(fēng)分離器壓降損失大幅降低的新型置件——減阻葉片。課題在閱讀大量前人研發(fā)成果,對(duì)旋風(fēng)分離器進(jìn)行深入了解的基礎(chǔ)上,利用計(jì)算流體動(dòng)力學(xué)方法(CFD),對(duì)傳統(tǒng)Lapple型旋風(fēng)分離器加設(shè)減阻裝置前后的內(nèi)部流場(chǎng)特征進(jìn)行仿真模擬,主要分析了流場(chǎng)的三維速度、壓強(qiáng)、旋度、湍流等性能參數(shù)的空間分布。首先,課題進(jìn)行物理模型的建立,包括確定分離器各個(gè)組成部分的幾何尺寸、模型繪制、網(wǎng)格劃分與生成等。選擇合理的數(shù)值模擬計(jì)算理論模型,設(shè)定初始條件；并通過(guò)利用前人實(shí)驗(yàn)研究結(jié)果,驗(yàn)證上述所選模型、操作參數(shù)。其次,基于實(shí)驗(yàn)室研究結(jié)果,本課題提出新型減阻裝置,并針對(duì)不同模型進(jìn)行數(shù)值模擬。實(shí)驗(yàn)室操作對(duì)象是傳統(tǒng)Lapple型旋風(fēng)分離器及加入五組不同長(zhǎng)度葉片后的分離器,目的在于得到兩種裝置主要性能指標(biāo)的實(shí)際值——收集效率(n)及壓降。數(shù)值模擬選用雷諾應(yīng)力模型(RSM),通過(guò)統(tǒng)計(jì)計(jì)算結(jié)果,得到氣相流場(chǎng)特征,如壓力場(chǎng)分布、湍流結(jié)構(gòu)等；初步分析減阻葉片長(zhǎng)度對(duì)旋風(fēng)分離器性能產(chǎn)生不同影響的機(jī)理。以單相流流場(chǎng)為前提,利用基于歐拉—拉格朗日方法的離散化模型(DPM)模擬不同粒徑顆粒在分離器內(nèi)的運(yùn)動(dòng)及分布。對(duì)傳統(tǒng)模型與L=I00mm分離器中單個(gè)顆粒的受力情況進(jìn)行計(jì)算并比較,同時(shí)模擬計(jì)算典型設(shè)備中作用在不同粒徑顆粒上離心力與徑向曳力的合力(Fc+Fr),闡明顆粒的最終走向。最后,為得到獲得減阻裝置優(yōu)化設(shè)計(jì),驗(yàn)證分離器內(nèi)產(chǎn)生壓降損耗的主要區(qū)域,考察大量過(guò)程變量：以長(zhǎng)度為100mm的葉片為基礎(chǔ),考察減阻葉片參數(shù)(疏密、寬度、組數(shù)等)變化對(duì)分離器性能的影響,分析減阻機(jī)理；同時(shí)提出改變溢流管結(jié)構(gòu)及在溢流管附近區(qū)域安裝制件得到新型分離模型,分析其與傳統(tǒng)Lapple型分離器性能及流場(chǎng)分布差異,得到分離器優(yōu)化設(shè)計(jì)。
[Abstract]:As a typical gas-solid separation equipment, the working mechanism of the cyclone separator mainly depends on the density difference between the air flow and the dust particles it carries, which leads to the spiral downward movement of both the cyclone separator and the cyclone separator once they enter the cyclone separator. A velocity slip is formed to separate particles from the movement of the main body of the airflow. The early cyclone separator was only widely used in the industrial field. With the development of cyclone separator year by year, the performance of the equipment has been continuously optimized, in addition to the cost, low operating costs, a wide range of operational environment, more and more attention has been paid to the various industries around the world. At present, micro cyclone separation has been gradually extended to air purification, food separation, biology, medicine and other precision industries. In order to further optimize the performance of the cyclone separator, the cognitive ability of the device has been developed from simple qualitative analysis to quantitative analysis of the flow field characteristics. However, the variation law of phase flow in cyclone separator is abnormal. Many scholars have to consider the negative effect of increasing pressure drop while optimizing various cyclone separator models to obtain higher efficiency. Aiming at the characteristics of the cyclone separator with medium efficiency and high pressure drop, this paper tries to improve the performance of the cyclone separator so that it can advance towards the ultimate goal of "ensuring efficiency and reducing drag". A new type of device, drag reducing blade, which can greatly reduce the pressure drop loss of cyclone separator, is presented. On the basis of reading a large number of previous research and development achievements and deeply understanding the cyclone separator, the subject uses the computational fluid dynamics (CFD),) method. The internal flow field characteristics of the traditional Lapple cyclone separator before and after the installation of drag reduction device are simulated. The spatial distribution of three dimensional velocity, pressure, curl, turbulence and other performance parameters of the flow field is mainly analyzed. Firstly, the physical model is built, including the geometric dimension of each component of the separator, model drawing, mesh generation and so on. A reasonable theoretical model of numerical simulation is selected to set the initial conditions, and the operation parameters are verified by using the results of previous experiments. Secondly, based on the results of laboratory research, a new type of drag reduction device is proposed, and numerical simulation is carried out for different models. The object of laboratory operation is the traditional Lapple cyclone separator and the separator after adding five groups of blades of different lengths. The purpose of the experiment is to obtain the actual values of the main performance indexes of the two kinds of equipment, namely, the collection efficiency (n) and the pressure drop. The Reynolds stress model (RSM),) is used for numerical simulation to obtain the characteristics of gas phase flow field, such as pressure field distribution and turbulent structure, and the mechanism of different influence of drag reducing blade length on the performance of cyclone separator is preliminarily analyzed. On the premise of single-phase flow field, the discrete model (DPM) based on Euler-Lagrangian method is used to simulate the movement and distribution of particles with different particle sizes in the separator. The forces acting on a single particle in the traditional model and the L=I00mm separator are calculated and compared. At the same time, the combined forces of centrifugal force and radial drag acting on different particle sizes in typical equipment are simulated and calculated to illustrate the final direction of the particles. Finally, in order to obtain the optimal design of drag reduction device and verify the main area of pressure drop loss in the separator, a large number of process variables are investigated: based on the blade with length of 100mm, the parameters of drag reducing blade (density, width, width) are investigated. The effect of the number of components on the performance of the separator and the mechanism of drag reduction are analyzed. At the same time, a new separation model is proposed by changing the structure of the overflow pipe and installing the components near the overflow pipe. The performance and flow field distribution difference between the new model and the traditional Lapple separator is analyzed, and the optimum design of the separator is obtained.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TQ051.8
本文編號(hào)：2319707
[Abstract]:As a typical gas-solid separation equipment, the working mechanism of the cyclone separator mainly depends on the density difference between the air flow and the dust particles it carries, which leads to the spiral downward movement of both the cyclone separator and the cyclone separator once they enter the cyclone separator. A velocity slip is formed to separate particles from the movement of the main body of the airflow. The early cyclone separator was only widely used in the industrial field. With the development of cyclone separator year by year, the performance of the equipment has been continuously optimized, in addition to the cost, low operating costs, a wide range of operational environment, more and more attention has been paid to the various industries around the world. At present, micro cyclone separation has been gradually extended to air purification, food separation, biology, medicine and other precision industries. In order to further optimize the performance of the cyclone separator, the cognitive ability of the device has been developed from simple qualitative analysis to quantitative analysis of the flow field characteristics. However, the variation law of phase flow in cyclone separator is abnormal. Many scholars have to consider the negative effect of increasing pressure drop while optimizing various cyclone separator models to obtain higher efficiency. Aiming at the characteristics of the cyclone separator with medium efficiency and high pressure drop, this paper tries to improve the performance of the cyclone separator so that it can advance towards the ultimate goal of "ensuring efficiency and reducing drag". A new type of device, drag reducing blade, which can greatly reduce the pressure drop loss of cyclone separator, is presented. On the basis of reading a large number of previous research and development achievements and deeply understanding the cyclone separator, the subject uses the computational fluid dynamics (CFD),) method. The internal flow field characteristics of the traditional Lapple cyclone separator before and after the installation of drag reduction device are simulated. The spatial distribution of three dimensional velocity, pressure, curl, turbulence and other performance parameters of the flow field is mainly analyzed. Firstly, the physical model is built, including the geometric dimension of each component of the separator, model drawing, mesh generation and so on. A reasonable theoretical model of numerical simulation is selected to set the initial conditions, and the operation parameters are verified by using the results of previous experiments. Secondly, based on the results of laboratory research, a new type of drag reduction device is proposed, and numerical simulation is carried out for different models. The object of laboratory operation is the traditional Lapple cyclone separator and the separator after adding five groups of blades of different lengths. The purpose of the experiment is to obtain the actual values of the main performance indexes of the two kinds of equipment, namely, the collection efficiency (n) and the pressure drop. The Reynolds stress model (RSM),) is used for numerical simulation to obtain the characteristics of gas phase flow field, such as pressure field distribution and turbulent structure, and the mechanism of different influence of drag reducing blade length on the performance of cyclone separator is preliminarily analyzed. On the premise of single-phase flow field, the discrete model (DPM) based on Euler-Lagrangian method is used to simulate the movement and distribution of particles with different particle sizes in the separator. The forces acting on a single particle in the traditional model and the L=I00mm separator are calculated and compared. At the same time, the combined forces of centrifugal force and radial drag acting on different particle sizes in typical equipment are simulated and calculated to illustrate the final direction of the particles. Finally, in order to obtain the optimal design of drag reduction device and verify the main area of pressure drop loss in the separator, a large number of process variables are investigated: based on the blade with length of 100mm, the parameters of drag reducing blade (density, width, width) are investigated. The effect of the number of components on the performance of the separator and the mechanism of drag reduction are analyzed. At the same time, a new separation model is proposed by changing the structure of the overflow pipe and installing the components near the overflow pipe. The performance and flow field distribution difference between the new model and the traditional Lapple separator is analyzed, and the optimum design of the separator is obtained.
【學(xué)位授予單位】：蘭州大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TQ051.8
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 林瑋,王乃寧;旋風(fēng)分離器內(nèi)三維兩相流場(chǎng)的數(shù)值模擬[J];動(dòng)力工程;1999年01期
，本文編號(hào)：2319707
本文鏈接：http://sikaile.net/kejilunwen/huaxuehuagong/2319707.html
最近更新
教材專(zhuān)著
