發(fā)布時(shí)間：2017-12-28 17:14

  本文關(guān)鍵詞：不同激勵(lì)方式對(duì)矩形聲場均勻性的影響　出處：《陜西師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 正弦信號(hào) 合成信號(hào) 諧振帶寬 聲場分布 均勻性

【摘要】：大功率超聲設(shè)備一般由超聲波發(fā)生器和超聲波換能器兩部分組成。由信號(hào)發(fā)生器產(chǎn)生特定頻率的信號(hào)激勵(lì)換能系統(tǒng),使系統(tǒng)保持在諧振狀態(tài)下工作。在大功率超聲的各類應(yīng)用中,聲場的分布情況對(duì)應(yīng)用效果的影響起著重要的作用。本文根據(jù)聲波疊加原理和波動(dòng)聲學(xué)理論,利用聲波的不相干性和擴(kuò)散聲場的特點(diǎn)設(shè)計(jì)出一種頻率連續(xù)變化的窄帶多頻合成信號(hào)激勵(lì)相應(yīng)換能系統(tǒng)工作,并結(jié)合實(shí)驗(yàn)研究對(duì)比分析了不同激勵(lì)方式下矩形聲場的分布情況。具體工作包括以下幾個(gè)方面：1根據(jù)波動(dòng)聲學(xué)理論和聲波疊加原理分析了單頻聲波和多頻不相干聲波在矩形空間的分布情況。研究表明：多頻下的聲場是由單頻大量的簡正振動(dòng)方式疊加與多頻不相干聲波疊加而成的,且頻率越高,簡正振動(dòng)方式越多,聲場越均勻。2根據(jù)白噪聲信號(hào)在固定頻帶寬度時(shí)頻譜連續(xù)且均勻的特點(diǎn),設(shè)計(jì)出經(jīng)帶通濾波器濾波之后的白噪聲信號(hào)作為多振子換能系統(tǒng)的激勵(lì)信號(hào),可以滿足系統(tǒng)保持長期穩(wěn)定工作的需求。本文采用Matlab軟件編程生成信號(hào),并經(jīng)過第三方軟件UltraWave將信號(hào)引入函數(shù)發(fā)生器,實(shí)現(xiàn)信號(hào)的分析。結(jié)果發(fā)現(xiàn)：白噪聲信號(hào)經(jīng)濾波之后幅值很低,不能驅(qū)動(dòng)相應(yīng)換能系統(tǒng)工作。進(jìn)一步提出并確定等幅正弦疊加的多頻合成信號(hào)作為系統(tǒng)的激勵(lì)信號(hào)。3將矩形超聲換能系統(tǒng)的諧振特性分別在小信號(hào)模式和大信號(hào)模式下進(jìn)行測量與分析,以便對(duì)合成信號(hào)的帶寬進(jìn)行準(zhǔn)確設(shè)計(jì)。研究發(fā)現(xiàn)：兩種激勵(lì)方式下系統(tǒng)的諧振特性是不同的,主要表現(xiàn)在：兩種方式下系統(tǒng)的諧振帶寬均隨著頻率的增加而加寬；系統(tǒng)在大信號(hào)激勵(lì)方式下諧振頻率fs和諧振帶寬△fs整體偏大。根據(jù)大功率超聲換能系統(tǒng)實(shí)際工作需要,確定依據(jù)大信號(hào)激勵(lì)方式下的諧振頻率和諧振帶寬作為合成信號(hào)參數(shù)設(shè)計(jì)的標(biāo)準(zhǔn)。4基于大信號(hào)方式下測得的諧振帶寬△fs,對(duì)信號(hào)分別在帶寬△f△fs、Δf=Δfs、ΔfΔfs進(jìn)行合成信號(hào)設(shè)計(jì),結(jié)合系統(tǒng)工作時(shí)的電參數(shù)和染色法聲場分布與正弦信號(hào)激勵(lì)下的情況進(jìn)行對(duì)比分析。結(jié)果表明：合成信號(hào)帶寬范圍設(shè)計(jì)在△f△fs時(shí),系統(tǒng)整體的性能較好,且在高頻系統(tǒng)中更為穩(wěn)定；電參數(shù)下的有功功率和電效率相比正弦信號(hào)呈現(xiàn)出稍微降低的趨勢(shì),且在低頻信號(hào)表現(xiàn)更為明顯,但聲場的均勻性都得到一定的改善。而在△f≥△fs,不論是電參數(shù)還是聲場均勻性方面,效果均不如△f△fs信號(hào)的情況。綜合分析指出合成信號(hào)的最佳帶寬選取在諧振帶寬一般時(shí),即△f=△fs/2,系統(tǒng)的各方面性能最好。5測試信號(hào)分別選取正弦信號(hào)和最佳帶寬的合成信號(hào)激勵(lì)矩形換能系統(tǒng),并通過銅版紙染色法和水聽器聲壓測量法對(duì)矩形槽內(nèi)的聲場進(jìn)行了測量與分析。實(shí)驗(yàn)結(jié)果表明：在聲場均勻性方面,高頻聲場優(yōu)于低頻聲場,合成信號(hào)優(yōu)于正弦信號(hào)。聲壓測點(diǎn)的平均效果表現(xiàn)為合成信號(hào)聲壓相對(duì)值大于對(duì)應(yīng)位點(diǎn)正弦信號(hào)聲壓相對(duì)值,間接地說明了合成信號(hào)的電聲轉(zhuǎn)化效率要高于正弦信號(hào)。
[Abstract]:The high power ultrasonic equipment is usually composed of two parts: ultrasonic generator and ultrasonic transducer. A signal generator is generated by a signal generator to stimulate the energy exchange system to keep the system working in a resonant state. In the various applications of high power ultrasound, the distribution of sound field plays an important role in the effect of the application. According to the principle of superposition and acoustic wave acoustics theory, the coherence and diffuse field acoustic features designed to change a narrow-band continuous frequency multi frequency synthesis signal excitation corresponding transducer system, and combined with the experimental study on comparative analysis of the distribution of rectangular field under different seismic excitations. The specific work includes the following aspects: 1. According to the wave acoustic theory and the superposition principle, the distribution of single frequency and multi frequency incoherent sound waves in rectangular space is analyzed. The research shows that the sound field at multiple frequencies is superimposed by a large number of single mode normal mode superposition and multiple frequency uncorrelated sound waves, and the higher the frequency, the more the normal mode of vibration is, the more uniform the sound field is. 2, according to the continuous and uniform spectrum of white noise signal in fixed band width, we design a white noise signal filtered by bandpass filter as the excitation signal of multi oscillator energy conversion system, which can meet the needs of long-term stable work of the system. In this paper, the signal is generated by Matlab software programming, and the signal is analyzed by introducing the signal into a function generator through third party software UltraWave. The results show that the amplitude of the white noise signal is very low after filtering, and it can not drive the work of the corresponding energy exchange system. The multi frequency synthetic signal with equal amplitude sinusoidal superposition is further proposed and determined as the excitation signal of the system. 3, the resonant characteristics of the rectangular ultrasonic energy conversion system are measured and analyzed under small signal mode and large signal mode respectively, so as to accurately design the bandwidth of the synthetic signal. The study found that: the resonant characteristics of two kinds of incentive modes of system is different, mainly in two ways: the resonant bandwidth system was widened with the increase of frequency; large signal excitation system in the resonant frequency of FS resonant FS overall larger bandwidth. According to the actual working needs of the high-power ultrasonic energy conversion system, we must determine the resonance frequency and the vibration bandwidth according to the large signal excitation mode as the design criteria of the synthetic signal parameters. 4 based on the mode of large signal measurement of the resonant bandwidth FS, the signal which are synthesized signal design in bandwidth delta f delta FS, Delta f=, delta FS, delta f delta FS, combined with the electrical parameters and dyeing method and field distribution of sine signal excitation system is working under the condition of comparative analysis. The results show that the synthetic signal bandwidth design in delta f delta FS, the overall system performance is better, and in the high frequency system is more stable; electrical parameters of the active power and power efficiency compared to the sinusoidal signal shows a slightly decreasing trend, and the performance in the low frequency signal is more obvious, but the uniformity of sound field to get some improvement. In the delta f delta FS, whether electric parameters or acoustic field uniformity, the effects are not the delta f delta FS signal. Comprehensive analysis points out that the optimum synthetic bandwidth signal selection in resonant bandwidth, namely Delta f= Delta fs/2, the best performance of the system. 5, the test signal selects the sinusoidal signal and the best bandwidth synthetic signal excitation rectangle energy conversion system respectively, and the sound field in the rectangular groove is measured and analyzed by the method of the coated paper stain and the hydrophone's sound pressure measurement. The experimental results show that the high frequency sound field is superior to the low frequency sound field in the field uniformity, and the synthetic signal is better than the sinusoidal signal. The average effect of sound pressure measurement points is that the relative value of synthetic signal pressure is greater than that of corresponding location sinusoidal signal, which indirectly indicates that the efficiency of synthetic signal's electroacoustic conversion is higher than that of sinusoidal signal.
【學(xué)位授予單位】：陜西師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB55

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