本文選題：射頻 + 泄漏電磁輻射��； 參考：《西北農(nóng)林科技大學(xué)》2015年碩士論文

【摘要】：射頻(Radiofrequency,RF)加熱是一種電磁介電加熱技術(shù),因其具有整體快速的加熱特性而被廣泛應(yīng)用于木材的干燥膠合、塑料焊接、農(nóng)產(chǎn)品及食品的生產(chǎn)加工業(yè)中。在射頻加熱技術(shù)大規(guī)模應(yīng)用于農(nóng)產(chǎn)品、食品加工領(lǐng)域的發(fā)展進程中,對加工工藝和加工設(shè)備的優(yōu)化改進著重要的工業(yè)化發(fā)展意義。論文主要從射頻加熱系統(tǒng)的輻射泄漏量和上極板電壓兩方面入手,對射頻加熱系統(tǒng)的設(shè)備特性進行研究,為該技術(shù)的工業(yè)化應(yīng)用和優(yōu)化提供技術(shù)參考和理論依據(jù)。安全和穩(wěn)定的系統(tǒng)運行條件對射頻加熱技術(shù)的工業(yè)化發(fā)展意義重大,然而關(guān)于射頻加熱系統(tǒng)輻射泄漏安全的研究卻很缺乏。研究針對實驗室內(nèi)兩臺27.12MHz射頻加熱系統(tǒng)進行了電磁輻射泄漏量檢測,并根據(jù)國際標(biāo)準(zhǔn)對系統(tǒng)的操作安全性進行了評估,并給出了相關(guān)優(yōu)化改進建議。在射頻加熱技術(shù)的工業(yè)化應(yīng)用研究中,有限元模擬以其具有方便、快速的特點而作為一項主要的研究手段。在對射頻加熱的模擬過程中,上極板電壓值是一項重要的輸入?yún)?shù),而且難以快速并準(zhǔn)確確定。論文基于分析、模擬和實際測量的方法,建立了極板電壓估算模型,實現(xiàn)了上極板電壓的精準(zhǔn)、快速估算,提高了計算機模擬研究效率。具體研究內(nèi)容和結(jié)論如下:(1)在輻射泄漏量研究試驗中,利用高頻電磁場強探測儀分別對不同測量距離、極板間距、加載狀況、屏蔽情況下的電場強度、磁場強度進行測量,并根據(jù)測量值計算功率密度,最后對射頻加熱系統(tǒng)物料出、入口屏蔽門簾的效果進行了分析。結(jié)果表明電場、磁場強度隨測量距離、極板間距的減小而增加。以1kg自來水作為射頻加熱負載,在加載情況下,隨著射頻輸出功率的增大,泄漏電場強度減小。Jiyuan射頻加熱系統(tǒng)的物料出口和入口處屏蔽門簾對電磁泄漏有明顯效果,泄漏電場強度和功率密度有顯著的減小。(2)極板間距130mm處泄漏電場、磁場強度的測量平均值均低于國際非電離輻射保護委員會(ICNIRP)和電氣與電子工程師協(xié)會(IEEE)的標(biāo)準(zhǔn)規(guī)定。為進一步減少操作人員在日常射頻加熱系統(tǒng)操作中受到的電磁輻射,建議在射頻加熱系統(tǒng)物料出入口增加屏蔽門簾、避免系統(tǒng)空載運行、減少操作人員在輻射區(qū)域的作業(yè)時間。(3)在5種不同的極板間距下分別對3kg黃豆的進行了射頻加熱試驗�；谠囼灲Y(jié)果建立了計算機模擬模型,得出模擬電壓。根據(jù)分壓和整流原理制作了上極板電壓檢測裝置來實際測量射頻加熱系統(tǒng)的上極板電壓。根據(jù)紅外熱像儀、光纖傳感器和熱電偶對物料實際加熱速率進行測量并通過分析計算法來計算上極板電壓。(4)電壓研究結(jié)果表明電壓值隨極板間距的減小、加熱速率的增加而增加。選擇物料三層平均溫度的計算電壓值和陽極、實測電流的回歸模型作為最佳電壓估算模型,并應(yīng)用于計算機模擬分析。
[Abstract]:RF heating is a kind of electromagnetic dielectric heating technology, which is widely used in wood drying bonding, plastic welding, agricultural products and food production and processing industry because of its integral and rapid heating characteristics. In the development process of large-scale application of RF heating technology in the field of agricultural products and food processing, it is of great significance to optimize and improve the processing technology and processing equipment. In this paper, the characteristics of RF heating system are studied from the aspects of radiation leakage and upper plate voltage, which provide a technical reference and theoretical basis for the industrial application and optimization of this technology. The safe and stable operating conditions of the system are of great significance to the industrial development of radio-frequency heating technology, but the research on the radiation leakage safety of the radio-frequency heating system is lacking. In this paper, the leakage of electromagnetic radiation is measured for two 27.12MHz RF heating systems in laboratory. The operating safety of the system is evaluated according to international standards, and some suggestions for optimization and improvement are given. In the industrial application of RF heating technology, finite element simulation is one of the main research methods because of its convenient and fast characteristics. In the simulation of RF heating, the voltage value of the upper pole is an important input parameter, and it is difficult to determine quickly and accurately. Based on the methods of analysis, simulation and actual measurement, a voltage estimation model of the electrode plate is established in this paper, which realizes the accurate and fast estimation of the voltage of the upper plate and improves the efficiency of computer simulation research. The specific research contents and conclusions are as follows: (1) in the radiation leakage research experiment, the high frequency electromagnetic field strong detector is used to measure the different measuring distance, the distance between the polar plates, the loading condition, the electric field intensity and the magnetic field intensity under the condition of shielding, respectively. The power density is calculated according to the measured value. Finally, the effect of shielding the door curtain at the entrance of the RF heating system is analyzed. The results show that the electric field and the magnetic field intensity increase with the decrease of the distance and the distance between the poles. Using 1kg tap water as RF heating load, with the increase of RF output power, the leakage electric field intensity decreases. Jiyuan RF heating system has obvious effect on electromagnetic leakage by shielding door curtain at the outlet and entrance of RF heating system. The leakage electric field intensity and power density are significantly reduced. The average magnetic field intensity is lower than the standard of ICNIRP (International Committee for the Protection of Non-ionizing radiation) and IEEE (Institute of Electrical and Electronic Engineers). In order to further reduce the electromagnetic radiation of operators in the daily operation of radio-frequency heating system, it is suggested that the screen curtain should be added at the material entrance of the RF heating system so as to avoid the system running without load. The radiofrequency heating experiments of 3kg soybeans were carried out under five different polar plate spacing to reduce the working time of operators in the radiation area. Based on the experimental results, a computer simulation model is established and the simulated voltage is obtained. According to the principle of partial voltage and rectifier, a device for measuring the upper plate voltage of RF heating system is made. According to the infrared thermal imager, optical fiber sensor and thermocouple, the actual heating rate of the material is measured and the voltage of the upper plate is calculated by the method of analysis and calculation. The results show that the voltage value decreases with the distance between the poles. The heating rate increases with the increase of heating rate. The calculated voltage and anode of the three-layer average temperature of the material are selected, and the regression model of the measured current is used as the best voltage estimation model, and applied to the computer simulation analysis.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O441.4

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