【摘要】：行波管自誕生以來就得到迅速發(fā)展和廣泛應(yīng)用。電子槍作為行波管的重要組成部分,對整管的工作性能起著決定性的作用。在具體模擬時(shí)工作人員發(fā)現(xiàn),電子槍模擬結(jié)果有時(shí)和實(shí)際工作狀態(tài)吻合較好,而有時(shí)會出現(xiàn)明顯不一致的情況。這是由于電子槍的數(shù)值計(jì)算是依賴電子光學(xué)CAD軟件而實(shí)現(xiàn)的,而設(shè)計(jì)師在使用軟件模擬電子槍時(shí)諸多參量一貫采用默認(rèn)設(shè)置,從而導(dǎo)致模擬結(jié)果與實(shí)際工作狀態(tài)出現(xiàn)差異。所以電子槍參量的準(zhǔn)確設(shè)置是至關(guān)重要的。本文主要對影響電子槍模擬結(jié)果的重要參量,包括陰極材料屬性、網(wǎng)格尺寸及虛陽極位置等進(jìn)行了研究與分析。通過電子槍模型對這些參量進(jìn)行模擬,研究得出準(zhǔn)確的參量取值方法。并對不同的軸對稱電子槍和柵控電子槍模型進(jìn)行分析模擬,驗(yàn)證了取值方法的合理性。研究結(jié)果表明,功函數(shù)和溫度對陰極電流影響很大,因根據(jù)實(shí)際測量設(shè)置,通常取在可穩(wěn)定發(fā)射的范圍內(nèi);在保證收斂情況下,選取相對較大網(wǎng)格值來提高模擬效率;人為設(shè)置的虛陽極位置嚴(yán)重影響發(fā)射電流,通過比較我們認(rèn)為,應(yīng)選擇陰極電流曲線極值點(diǎn)處作為虛陽極的準(zhǔn)確位置。本文對影響電子槍模擬結(jié)果的其他重要參量,如:有限元階次、局部對稱計(jì)算、自適應(yīng)及求解維數(shù)等也進(jìn)行了研究與分析。將這些參量分別對柵控電子槍和軸對稱電子槍兩類模型進(jìn)行模擬,并得到變化曲線。研究得出,準(zhǔn)確模擬電子槍時(shí),可首先選擇有限元線性插值、1/4局部對稱、非自適應(yīng)和三維計(jì)算。通過分析這些參量,可以將模擬結(jié)果、計(jì)算時(shí)間和占用資源三部分進(jìn)行更好的協(xié)調(diào),在保證計(jì)算精度的前提下提高模擬效率。本文提出了軸對稱及柵控電子槍重要參量的取值方法。通過電子槍模型,分別采用本文提出的與軟件默認(rèn)的兩種參數(shù)設(shè)置方法進(jìn)行模擬,并將其仿真結(jié)果進(jìn)行對比。研究結(jié)果表明本文提出的參數(shù)取值方法具有重要作用與意義,為同行業(yè)內(nèi)人士提供了方便有效的模擬仿真流程,縮短了電子槍的優(yōu)化周期,避免了不必要的人力和材料等資源的浪費(fèi)。
[Abstract]:Traveling wave tube (TWT) has been rapidly developed and widely used since its birth. As an important part of traveling wave tube (TWT), electron gun plays a decisive role in the performance of the whole tube. During the simulation, it is found that the simulation results of electron gun are in good agreement with the actual working state, and sometimes there are obvious inconsistencies. This is because the numerical calculation of electron gun depends on the electron optics CAD software, and the designer always uses default setting when simulating electron gun with software, which results in the difference between the simulation result and the actual working state. Therefore, the accurate setting of electron gun parameters is very important. In this paper, the important parameters affecting the simulation results of electron gun, including the properties of cathode material, grid size and virtual anode position, are studied and analyzed. These parameters are simulated by electron gun model, and the accurate parameter selection method is obtained. The different models of axisymmetric electron gun and gate controlled electron gun are analyzed and simulated, and the rationality of the method is verified. The results show that the work function and temperature have a great influence on the cathodic current because it is usually within the range of stable emission according to the actual measurement setting and the relatively large grid value is chosen to improve the simulation efficiency under the condition of ensuring convergence. The position of artificial virtual anode seriously affects the emission current. We think that the extreme point of cathodic current curve should be chosen as the exact position of virtual anode. Other important parameters affecting the simulation results of electron gun, such as finite element order, local symmetry calculation, self-adaptation and solving dimension, are also studied and analyzed in this paper. These parameters are used to simulate the gate-controlled electron gun and the axisymmetric electron gun, and the variation curves are obtained. It is found that the finite element linear interpolation, 1 ~ 4 local symmetry, non-adaptive and three-dimensional calculation can be selected in the accurate simulation of electron gun. Through the analysis of these parameters, the simulation results, calculation time and resources can be better coordinated, and the simulation efficiency can be improved on the premise of ensuring the accuracy of calculation. In this paper, a method for determining the important parameters of axisymmetric and gate-controlled electron gun is presented. By means of electron gun model, two methods of parameter setting, which are proposed in this paper and software default, are used to simulate, and the simulation results are compared with each other. The results show that the method proposed in this paper has an important role and significance. It provides a convenient and effective simulation flow for the peers in the industry, and shortens the optimization period of electron gun. It avoids unnecessary waste of resources such as manpower and materials.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN124

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本文編號：2450412