本文關(guān)鍵詞： 圓柱液膜 線性穩(wěn)定性 色散關(guān)系式 表面波增長率　出處：《長安大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：本文主要對圓柱液膜射流的線性穩(wěn)定性進(jìn)行了分析,從已知理論我們可以知道表面波增長率是影響圓柱液膜射流穩(wěn)定性的一個(gè)特征因素。但是從推導(dǎo)得到的色散關(guān)系式中,我們可以看出表面波增長率和表面波數(shù)之間的關(guān)系是隱含給出的,它的解析解不能通過直接求解得到,所以需應(yīng)用Fortran語言,采用Muller迭代方法編制相應(yīng)的程序求得數(shù)值解。在分析過程中,通過改變輸入?yún)?shù)的值來得到不同條件下的表面波增長率隨表面波數(shù)的變化關(guān)系,可以得知液流速度lU、雷諾數(shù)lRe、馬赫數(shù)Ma、韋伯?dāng)?shù)lWe、歐拉數(shù)lEu、歐尼索數(shù)lOh這些量綱一參數(shù)對圓柱液體射流的穩(wěn)定性都有著十分重要的影響。把編程輸出的數(shù)據(jù)繪制成圖,對圓柱液膜的線性穩(wěn)定性進(jìn)行了分析:圓射流的單股狀正對稱波形(n=0)、反對稱波形(n=1)、雙股狀正對稱波形(n=2)、三股狀反對稱波形(n=3)這四種情況所繪制出的曲線的形狀都呈倒U型,當(dāng)表面波數(shù)k值增大時(shí),表面波增長率r?出現(xiàn)先增大后減小的趨勢。也就是隨表面波數(shù)的增加,表面波增長率都有一個(gè)最大值,這個(gè)峰值表示了圓柱液膜射流在此表面波增長率下最有可能碎裂,此時(shí)相對應(yīng)的波數(shù)稱為支配波數(shù)即為最易導(dǎo)致圓柱液膜射流碎裂的表面波波數(shù);本文也論述了韋伯?dāng)?shù)對圓射流的影響,隨著韋伯?dāng)?shù)lWe逐漸增大,支配波數(shù)domk在逐漸增大,與其對應(yīng)的支配表面波增長率domr,?也在增大,這可以說明在表面張力很小的情況下,空氣動(dòng)力的作用越大,液體表面波碎裂的可能性越大;在本文中通過比較單股狀圓柱液體的正對稱波形和反對稱波形,可以得知韋伯?dāng)?shù)相同時(shí),正對稱波形的表面波增長率要比反對稱波形的表面波增長率大,這可以說明比起正對稱波形來,反對稱波形的表面波更穩(wěn)定。也就是說正對稱波形的表面波比反對稱波形的表面波更易碎裂。所以,在霧化過程中,正對稱波形的表面波將起主導(dǎo)作用,反對稱波形的表面波起次要作用;比較正對稱與反對稱波形的韋伯?dāng)?shù),它們的大小是不相同的,反對稱波形的韋伯?dāng)?shù)比正對稱波形的韋伯?dāng)?shù)大,當(dāng)韋伯?dāng)?shù)比較大時(shí),圓柱液體的表面波增長率較大,此時(shí)圓柱液體更容易碎裂。由于圓射流速度為低、中速時(shí)容易形成正對稱波形的表面波,而中高速圓柱液體則易形成反對稱波形的表面波,所以對于許多實(shí)際噴霧來說,對于反對稱波形的研究比對正對稱波形的研究更有重大意義;在本文中還對不同階數(shù)下的圓柱液體的表面波增長率進(jìn)行了分析,可以得知單股狀圓柱液體的霧化效果比雙股狀、三股狀圓柱液體的霧化效果要好;本文還論述了液體粘性對圓射流的影響,從分析結(jié)果可知隨著圓柱液體粘度的增大,表面波增長率在逐漸地變小,這可以說明液體粘性的增大使得液體表面波愈趨于穩(wěn)定,圓柱液體更不容易碎裂,使得霧化效果變差。
[Abstract]:In this paper, the linear stability of liquid film jet is analyzed. From the known theory we can know that the growth rate of surface wave is a characteristic factor affecting the stability of cylindrical liquid film jet. We can see that the relationship between the growth rate of surface wave and the number of surface wave is given implicitly, its analytical solution can not be obtained by direct solution, so we need to use Fortran language. The numerical solution is obtained by using the Muller iterative method. In the process of analysis, the relationship between the surface wave growth rate and the surface wave number under different conditions is obtained by changing the value of the input parameters. The velocity of liquid flow, Reynolds number, Mach number, Weber number and Euler number lEu can be obtained. The dimensionality parameters of lOh are very important to the stability of liquid jet. The linear stability of cylindrical liquid film is analyzed as follows: the single-strand normal symmetric waveform of circular jet, the anti-symmetric waveform, and the double-strand normal-symmetric waveform. The shape of the curves drawn in these four cases is inverted U shape. When the surface wave number k increases, the growth rate of the surface wave is r? With the increase of the surface wave number, the growth rate of the surface wave has a maximum value, which indicates that the cylindrical liquid film jet is most likely to break down under the growth rate of the surface wave. The corresponding wave number is called dominant wave number which is the surface wave number which is the most likely to lead to the breakup of cylindrical liquid film jet. The influence of Weber number on circular jet is also discussed in this paper. With the increasing of Weber number lWe, the dominating wavenumber domk is gradually increasing, and the corresponding dominating surface wave growth rate is domr? It can be concluded that the greater the effect of aerodynamic force is, the greater the possibility of surface wave fragmentation is when the surface tension is very small. In this paper, by comparing the normal and antisymmetric waveforms of single-stranded cylindrical liquids, we can find that the growth rate of the surface waves of the normal symmetric waveforms is higher than that of the antisymmetric waveforms when the Weber number is the same. This shows that the surface wave of the antisymmetric waveform is more stable than that of the symmetric waveform. That is to say, the surface wave of the symmetric waveform is more easily broken than the surface wave of the antisymmetric waveform. Therefore, in the atomization process. The surface wave of the symmetric waveform will play a leading role, and the surface wave of the antisymmetric waveform will play a secondary role. The Weber numbers of symmetric and antisymmetric waveforms are different. The number of Weber of antisymmetric waveforms is larger than that of positive symmetric waveforms, when the number of Weber numbers is larger. The growth rate of surface wave of cylindrical liquid is large, and the cylindrical liquid is more easily broken. Due to the low velocity of circular jet, the surface wave with normal symmetry wave can easily be formed at medium velocity. But the medium and high speed cylindrical liquid is easy to form the surface wave of the antisymmetric waveform, so for many practical spray, the research on the antisymmetric waveform is more important than the study of the normal symmetric waveform. In this paper, the surface wave growth rate of cylindrical liquid with different order is also analyzed. It can be found that the atomization effect of single-stranded cylindrical liquid is better than that of double-stranded cylindrical liquid, and the atomization effect of triplicate cylindrical liquid is better than that of double-stranded cylindrical liquid. The effect of liquid viscosity on circular jet is also discussed in this paper. The results show that the growth rate of surface wave becomes smaller with the increase of liquid viscosity. It can be concluded that the increase of liquid viscosity makes the surface wave of liquid more stable and the cylindrical liquid more difficult to break down, which makes the atomization effect worse.
【學(xué)位授予單位】：長安大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TK05

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 邵超;射流碎裂理論與實(shí)驗(yàn)的對比研究[D];長安大學(xué);2015年

，

本文編號：1471654