發(fā)布時(shí)間：2018-05-21 08:18

  本文選題：磁流體動(dòng)力學(xué) + 壁面粗糙度　； 參考：《內(nèi)蒙古大學(xué)》2016年博士論文

【摘要】：隨著微全分析系統(tǒng)(micro total ananysis system,簡(jiǎn)稱μTAS):和微機(jī)電系統(tǒng)(micro electro mechanical system,簡(jiǎn)稱MEMS)的發(fā)展,微流體的驅(qū)動(dòng)和控制技術(shù)備受關(guān)注.微流控系統(tǒng)通常利用外加的電場(chǎng)和磁場(chǎng)來(lái)驅(qū)動(dòng)并控制微管道內(nèi)導(dǎo)電流體(電解質(zhì)溶液或液態(tài)金屬)的流動(dòng).這種由外加電磁場(chǎng)作用下產(chǎn)生的流動(dòng)稱為電磁驅(qū)動(dòng)流或磁流體動(dòng)力學(xué)流(magnetohydrodynamic flow,簡(jiǎn)稱MHD流),它的優(yōu)點(diǎn)是電極電壓較低而流量較高且有良好的生物相容性.自20世紀(jì)末以來(lái),國(guó)內(nèi)外眾多學(xué)者從理論和實(shí)驗(yàn)方面對(duì)微管道內(nèi)MHD流進(jìn)行了研究并取得了很多重要的成果,并且已在生物、醫(yī)學(xué)和化學(xué)等領(lǐng)域獲得了重要的應(yīng)用.但以上研究均沒(méi)有考慮壁面粗糙度對(duì)MHD流的影響,而設(shè)備的制造過(guò)程或其他物質(zhì)(如大分子)在壁面上的沉淀都會(huì)引起微管道的壁面粗糙度,在實(shí)際問(wèn)題中,有時(shí)為了提高微管道內(nèi)流體的混合效率,管道壁面上也可能會(huì)人為地設(shè)計(jì)一些粗糙度.在微管道中,壁面粗糙度和管道半徑之比大于常規(guī)尺度管道內(nèi)的比值,因此,由壁面粗糙引起的速度擾動(dòng)能傳遞到主流區(qū)而影響整個(gè)微流動(dòng)。另外,管道內(nèi)的流體流動(dòng)時(shí)會(huì)出現(xiàn)壁面滑移現(xiàn)象,并壁面滑移速度與流體所受的剪切率成正比,即uslip=uslip-uwall=b|αu/αy|wall,其中滑移長(zhǎng)度b是微米量級(jí)的.在常規(guī)尺度管道內(nèi)的流體研究中,我們可以忽略壁面滑移現(xiàn)象.但是,在微管道內(nèi),壁面渭移對(duì)流體流動(dòng)有很大的影響,因此,在微流體研究中,壁面滑移現(xiàn)象是應(yīng)該考慮的重要因素之一.基于這一現(xiàn)狀,本文將圍繞壁面粗糙度和滑移對(duì)MHD流的影響展開(kāi)研究,主要采用攝動(dòng)展開(kāi)法研究以下幾類問(wèn)題：(1)縱向正弦形壁面粗糙度對(duì)平行板微管道內(nèi)直流MHD流(簡(jiǎn)稱DC MHD流)的影響。縱向壁面粗糙度指的是平行于流體流向的粗糙度.具有縱向正弦形壁面粗糙度的微管道內(nèi),管道垂直于流體流向的截面沿流動(dòng)方向不發(fā)生改變.本文采用攝動(dòng)法展開(kāi)得到了具有縱向正弦形壁面粗糙度的平行板微管道內(nèi)DC MHD流的速度和流率的近似解析解。結(jié)果表明：粗糙度對(duì)DC MHD流的影響隨著哈特曼數(shù)的增加而減小；當(dāng)粗糙度波數(shù)或哈特曼數(shù)充分大時(shí),上下板壁面粗糙度的相位差對(duì)流動(dòng)影響可忽略不計(jì)；隨粗糙度波數(shù)的增加,粗糙度對(duì)流動(dòng)的阻力也會(huì)增加；當(dāng)粗糙度波數(shù)小于臨界波數(shù)并相位差等于πc時(shí),壁面粗糙度能提高DCMHD流的平均速度.(2)橫向正弦形壁面粗糙度對(duì)平行板微管道內(nèi)DC MHD流動(dòng)的影響.橫向壁面粗糙度指的是垂直于流體流動(dòng)方向的粗糙度。具有橫向正弦形壁面粗糙度的微管道內(nèi),管道垂直于流體流向的截面沿流動(dòng)方向發(fā)生改變。本文利用攝動(dòng)展開(kāi)法求出了具有橫向正弦形壁面粗糙度的平行板微管道內(nèi)DC MHD流的流函數(shù)的近似解析解,并得到了流率和粗糙度之間的關(guān)系.結(jié)果表明：對(duì)任意給定的粗糙度相位差,流率因橫向粗糙度的出現(xiàn)而減小；粗糙度對(duì)流動(dòng)的阻力隨相位差和波數(shù)的增加而增加,隨哈特曼數(shù)的增加而減小；當(dāng)粗糙度波數(shù)充分大時(shí),粗糙度相位差對(duì)流動(dòng)的影響可忽略不計(jì).(3)壁面滑移和縱向正弦形壁面粗糙度對(duì)平行板微管道內(nèi)交流MHD流的影響.本文利用攝動(dòng)展開(kāi)法求出了具有縱向壁面粗糙度的平行板微管道內(nèi)時(shí)間周期MHD滑移流的速度和電勢(shì)的近似解析解,并得到了平均速度振幅和粗糙度之間的關(guān)系.結(jié)果表明：速度和電勢(shì)分布出現(xiàn)了明顯的波動(dòng)現(xiàn)象；速度和電勢(shì)之間存在相位滯后(phase lag),且相位滯后隨頻率、滑移長(zhǎng)度的增加而增加,隨哈特曼數(shù)、波數(shù)和粗糙度相位差的增加而減小,而對(duì)充分小的頻率,相位滯后幾乎不存在,當(dāng)波數(shù)充分大時(shí),粗糙度相位差對(duì)相位滯后的影響可忽略不計(jì)；速度振幅隨滑移長(zhǎng)度的增加而增加,隨頻率、波數(shù)和相位差的增加而減小,但是,當(dāng)波數(shù)充分大時(shí),相位差對(duì)速度振幅幾乎沒(méi)有影響,當(dāng)頻率充分大時(shí),速度振幅不受滑移長(zhǎng)度的影響.本文還研究了縱向正弦形粗糙度對(duì)平行板微管道內(nèi)電滲、電磁混合驅(qū)動(dòng)流的影響和三維粗糙度對(duì)平行板微管道內(nèi)電滲流的影響。利用攝動(dòng)展開(kāi)法求出了速度和電勢(shì)近似解析解,分析了粗糙度波數(shù)、zeta勢(shì)、雙電層厚度的倒數(shù)、哈特曼數(shù)等無(wú)量綱參數(shù)對(duì)流動(dòng)的影響.在本文中得到結(jié)果能為微流控設(shè)備的設(shè)計(jì)、優(yōu)化、發(fā)展奠定理論基礎(chǔ).
[Abstract]:With the development of micro total ananysis system (ananysis system), and the development of micro electro mechanical system (MEMS), micro fluid drive and control technology has attracted much attention. Microfluidic systems usually use applied electric field and magnetic field to drive and control the conductance body (electrolyte solution or liquid) in micropipeline. The flow of the state metal. This flow produced by the external electromagnetic field is called the electromagnetic driving flow or the magnetohydrodynamic flow (magnetohydrodynamic flow). Its advantages are the low electrode voltage, high flow rate and good biocompatibility. Since the end of the twentieth Century, many scholars at home and abroad have been from the theoretical and experimental aspects. MHD flow in micropipes has been studied and many important achievements have been achieved, and important applications have been obtained in biological, medical and chemical fields. However, the effects of wall roughness on MHD flow are not considered, and the manufacturing process of equipment or other substances (such as macromolecules) on the wall will cause micro pipes. In practical problems, in practical problems, in order to improve the mixing efficiency of the fluid in the micro pipe, some roughness may be artificially designed on the wall of the pipe. In the microchannel, the ratio of the wall roughness to the pipe radius is greater than that in the conventional pipe. Therefore, the velocity disturbance caused by the wall roughness can be transferred to the mainstream. In addition, the wall slip phenomenon occurs when the fluid flows in the pipe, and the velocity of the wall slip is proportional to the shear rate of the fluid, that is, uslip=uslip-uwall=b| alpha u/ alpha y|wall, in which the slip length B is micrometer. In the fluid study in the conventional pipe, we can ignore the slip of the wall. However, in the micro pipeline, the wall Wei shift has a great influence on the flow of the fluid. Therefore, the wall slip phenomenon is one of the important factors to be considered in the study of the microfluidics. Based on this situation, this paper will focus on the influence of the wall roughness and slip on the MHD flow. (1) the influence of the longitudinal sine wall roughness on the direct current MHD flow (DC MHD flow) in the parallel plate micropipeline. The longitudinal wall roughness refers to the roughness of the flow direction parallel to the flow direction. In the microchannel with the longitudinal sinusoidal surface roughness, the cross section of the pipe perpendicular to the flow direction does not change along the flow direction. The approximate analytical solution of the velocity and flow rate of the DC MHD flow in a parallel plate micro pipe with a longitudinal sinusoidal surface roughness is obtained by the dynamic method. The results show that the influence of the roughness on the DC MHD flow decreases with the increase of the Hartmann number; the phase difference convection of the roughness of the upper and lower plate wall surface is the same as the number of roughness wave or the number of waves. The dynamic effect is negligible; with the increase of the roughness wave number, the resistance of the roughness to the flow is also increased; when the roughness wave number is less than the critical wave number and the phase difference equals PI C, the wall roughness can increase the average velocity of the DCMHD flow. (2) the effect of the transverse sine wall roughness on the DC MHD flow in the flat plate micropipeline. The roughness refers to the roughness perpendicular to the flow direction of the fluid. In a microchannel with the roughness of the transverse sinusoidal wall, the cross section of the pipe perpendicular to the flow direction changes along the flow direction. In this paper, the flow function of the DC MHD flow in the flat plate micro pipe with the transverse sinusoidal surface roughness is obtained by the perturbation expansion method. The relationship between the flow rate and the roughness is obtained. The results show that the flow rate decreases with the appearance of the transverse roughness for any given degree of roughness, and the resistance of the roughness to the flow increases with the increase of the phase difference and wave number, and decreases with the increase of the Hartmann number; when the number of roughness waves is sufficiently large, the roughness is large. The effect of phase difference on flow can be neglected. (3) the influence of wall slip and longitudinal sine wall roughness on the AC MHD flow in the parallel plate micropipeline. In this paper, the approximate analytical solution of the velocity and potential of the time periodic MHD slip flow in a parallel plate micro pipe with the longitudinal wall roughness is obtained by the perturbation expansion method. The relationship between the average velocity amplitude and the roughness shows that the velocity and potential distribution have obvious fluctuations, and there is a phase lag between the velocity and the potential (phase lag), and the phase lag increases with the increase of the frequency and the slip length, and decreases with the increase of the Hartmann number, the wave number and the phase difference of the roughness. When the wave number is large, the phase lag effect of the roughness is negligible when the wave number is large. The velocity amplitude increases with the increase of the slip length, and decreases with the increase of the frequency, wave number and phase difference, but when the wave number is sufficiently large, the phase difference has little effect on the velocity amplitude, when the frequency is filled. In addition, the velocity amplitude is not affected by the slip length. The influence of the longitudinal sinusoidal roughness on the electroosmosis in the parallel plate micropipeline, the influence of the electromagnetic mixed driven flow and the three-dimensional roughness on the electroosmotic seepage in the parallel plate micro pipe are also studied. The effect of the dimensionless parameters, such as the zeta potential, the reciprocal of the thickness of the double layer and the Hartmann number, on the flow, can be obtained in this paper to lay a theoretical foundation for the design, optimization and development of the microfluidic equipment.
【學(xué)位授予單位】：內(nèi)蒙古大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：O441;O357.3

【參考文獻(xiàn)】

相關(guān)期刊論文 前7條

1 趙凌志;李建;彭燕;;磁流體微泵研究進(jìn)展及其關(guān)鍵問(wèn)題[J];北京生物醫(yī)學(xué)工程;2011年05期

2 ;EXPERIMENTAL STUDY ON ALTERNATING MAGNETIC FIELD MAGNETOHYDRODYNAMIC PUMP[J];Journal of Hydrodynamics;2008年05期

3 張春平;唐大偉;韓鵬;祝捷;;粗糙度對(duì)微細(xì)圓管內(nèi)流動(dòng)特性影響的攝動(dòng)分析[J];工程熱物理學(xué)報(bào);2008年05期

4 宋述軍;彭燕;沙次文;凌金福;;交流磁流體推進(jìn)血液驅(qū)動(dòng)裝置的初步研究[J];中國(guó)生物醫(yī)學(xué)工程學(xué)報(bào);2006年05期

5 王昊利,王元,劉江;平板微通道壁面粗糙度對(duì)流場(chǎng)影響的攝動(dòng)分析[J];西安交通大學(xué)學(xué)報(bào);2005年05期

6 王沫然,李志信;基于MEMS的微泵研究進(jìn)展[J];傳感器技術(shù);2002年06期

7 馮焱穎,周兆英,葉雄英,湯揚(yáng)華;微流體驅(qū)動(dòng)與控制技術(shù)研究進(jìn)展[J];力學(xué)進(jìn)展;2002年01期

相關(guān)博士學(xué)位論文 前3條

1 郭春海;電磁力擾動(dòng)作用下微管道中液體流動(dòng)與混合的特性研究[D];南京理工大學(xué);2012年

2 楊胡坤;微流體的電滲驅(qū)動(dòng)及其相關(guān)技術(shù)的研究[D];哈爾濱工業(yè)大學(xué);2008年

3 關(guān)艷霞;微流控分析系統(tǒng)中微流體驅(qū)動(dòng)技術(shù)的研究[D];東北大學(xué);2006年

，

本文編號(hào)：1918441