本文選題：電容層析成像 + 大尺度傳感器　； 參考：《中國科學(xué)院大學(xué)(中國科學(xué)院工程熱物理研究所)》2017年碩士論文

【摘要】：多相流系統(tǒng)廣泛存在于石油、制藥、化工等工業(yè)應(yīng)用領(lǐng)域,實(shí)現(xiàn)上述多相流過程的實(shí)時在線測量對理解多相流過程的機(jī)理、優(yōu)化多相流過程意義重大。電容層析成像技術(shù)是一項(xiàng)可實(shí)現(xiàn)有效實(shí)時測量的多相流檢測技術(shù)。該技術(shù)的諸多優(yōu)點(diǎn),如非侵入、非接觸、無輻射、造價(jià)低、采集速度快,使其廣泛應(yīng)用于多相流過程的檢測。但是,電容層析成像技術(shù)在大型化過程中也面臨諸多挑戰(zhàn),如提高傳感器的敏感性以及提高大尺度電容傳感器的空間分辨率等。本文的目的是探索提高大尺度電容層析成像傳感器空間分辨率的有效方法,文中涉及到了兩種解決方法:通過改變電極激勵模式提高傳感器的敏感性從而來提高分辨率以及通過改變電極結(jié)構(gòu)來提高空間分辨率。研究方法包括數(shù)值仿真以及實(shí)驗(yàn)研究。利用數(shù)值仿真方法主要研究了不同的電極結(jié)構(gòu)以及不同的外層電極數(shù)對大尺度電容傳感器成像效果的影響。仿真過程中設(shè)計(jì)了三種ECT傳感器,即只有外層電極結(jié)構(gòu)的ECT傳感器(EE)、含有內(nèi)外雙層電極結(jié)構(gòu)的ECT傳感器(IEE)以及組合結(jié)構(gòu)的ECT傳感器(CE)。另外還改變了不同結(jié)構(gòu)的傳感器的外層電極數(shù),重構(gòu)圖像算法用到了三種:線性反投影算法(LBP)、Landweber迭代算法以及修正的Landweber迭代算法。最后總結(jié)了外層電極數(shù)在不同的重構(gòu)圖像算法下對不同結(jié)構(gòu)的ECT傳感器最終成像效果的影響,同時依據(jù)仿真結(jié)果確定了實(shí)驗(yàn)過程中用到的傳感器的電極結(jié)構(gòu)。實(shí)驗(yàn)研究包括兩部分:不同激勵模式對大尺度IEE結(jié)構(gòu)的傳感器的成像效果的影響以及不同的傳感器結(jié)構(gòu)對大尺度ECT傳感器的性能的影響。在激勵模式的研究過程中設(shè)計(jì)了 一個大尺度IEE結(jié)構(gòu)傳感器,利用該傳感器研究了五種雙電極激勵模式和傳統(tǒng)單電極激勵模式對該傳感器成像效果的影響。對比了不同激勵模式下利用LBP算法獲得的重構(gòu)圖像,同時引入了一種修正的重構(gòu)方法來減小重構(gòu)圖像過程中噪聲的干擾。最后利用重構(gòu)圖像的固體濃度的相對誤差評價(jià)了六種激勵模式的精度。在研究大尺度ECT傳感器結(jié)構(gòu)產(chǎn)生的性能影響方面,設(shè)計(jì)了上述三種結(jié)構(gòu)的大尺度ECT傳感器,對比了不同結(jié)構(gòu)的ECT傳感器的成像效果。重構(gòu)圖像使用的算法依然是LBP算法,但是該實(shí)驗(yàn)中重構(gòu)圖像用了兩種歸一化方式,對比了不同的歸一化方式對不同結(jié)構(gòu)的ECT傳感器最終成像效果的影響,最終利用重構(gòu)圖像的固體濃度評估了兩種歸一化應(yīng)用于不同結(jié)構(gòu)的ECT傳感器時的性能。
[Abstract]:Multiphase flow systems are widely used in petroleum, pharmaceutical, chemical and other industrial applications. It is of great significance to realize the real-time on-line measurement of the multiphase flow process in order to understand the mechanism of the multiphase flow process and optimize the multiphase flow process. Electrical capacitance tomography (ECT) is a multiphase flow detection technique which can be used for real-time measurement. The advantages of this technology, such as non-invasion, non-contact, non-radiation, low cost and fast acquisition speed, make it widely used in the detection of multiphase flow process. However, the capacitance tomography technology also faces many challenges in the large-scale process, such as enhancing the sensitivity of the sensor and improving the spatial resolution of the large-scale capacitance sensor. The purpose of this paper is to explore an effective method to improve the spatial resolution of large scale capacitance tomography sensor. Two solutions are involved in this paper: to improve the sensitivity of the sensor by changing the electrode excitation mode to improve the resolution and to improve the spatial resolution by changing the electrode structure. The research methods include numerical simulation and experimental research. The effects of different electrode structures and the number of outer electrodes on the imaging effect of large scale capacitive sensor are studied by numerical simulation. In the process of simulation, three kinds of ECT sensors are designed, namely, ECT sensors with outer electrode structure, ECT sensors with internal and external double-layer electrode structure, and ECT sensors with combined structure. In addition, the number of outer electrodes of sensors with different structures is changed, and three kinds of image reconstruction algorithms are used: the linear backprojection algorithm and the modified Landweber iterative algorithm. Finally, the effects of the number of outer electrodes on the final imaging of ECT sensors with different structures under different reconstructed image algorithms are summarized, and the electrode structure of the sensors used in the experiment is determined according to the simulation results. The experimental study consists of two parts: the influence of different excitation modes on the imaging effect of large scale IEE sensors and the influence of different sensor structures on the performance of large scale ECT sensors. A large scale IEE structure sensor is designed in the research of excitation mode. The effects of five two electrode excitation modes and the traditional single electrode excitation mode on the imaging effect of the sensor are studied. The reconstructed images obtained by using LBP algorithm under different excitation modes are compared, and a modified reconstruction method is introduced to reduce the noise interference in the process of image reconstruction. Finally, the relative error of solid concentration of reconstructed image is used to evaluate the accuracy of six excitation modes. In order to study the effect of large scale ECT sensor structure on the performance, the three kinds of large scale ECT sensors are designed, and the imaging effects of ECT sensors with different structures are compared. The algorithm used for image reconstruction is still LBP algorithm, but in this experiment, two normalization methods are used to reconstruct the image, and the effects of different normalization methods on the final imaging effect of ECT sensors with different structures are compared. Finally, the performance of two normalized ECT sensors with different structures is evaluated by using the solid concentration of reconstructed images.
【學(xué)位授予單位】：中國科學(xué)院大學(xué)(中國科學(xué)院工程熱物理研究所)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TP391.41;TP212

【參考文獻(xiàn)】

相關(guān)期刊論文 前5條

1 張嬌龍;毛明旭;葉佳敏;王海剛;;流化床干燥過程壓力和電容層析成像測量分析[J];工程熱物理學(xué)報(bào);2016年03期

2 羅琴;趙銀峰;葉茂;劉中民;;電容層析成像在氣固流化床測量中的應(yīng)用[J];化工學(xué)報(bào);2014年07期

3 張雨;于才淵;張人瀚;;氣固移動流化床干燥器流化與傳熱特性研究[J];干燥技術(shù)與設(shè)備;2008年02期

4 陳琪;劉石;閻潤生;;下行床內(nèi)顆粒濃度的電容層析成像測量的研究[J];熱科學(xué)與技術(shù);2007年02期

5 張修剛,王棟,林宗虎;近期多相流過程層析成像技術(shù)的發(fā)展[J];熱能動力工程;2004年03期

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