柴油機(jī)分流氣體對沖排氣消聲單元?dú)饬魉俣确治鲅芯?/H1>
發(fā)布時(shí)間：2018-03-06 08:38
本文選題：柴油機(jī) 切入點(diǎn)：消聲器 出處：《內(nèi)蒙古農(nóng)業(yè)大學(xué)》2017年博士論文 論文類型：學(xué)位論文
【摘要】：安裝排氣消聲器是控制柴油機(jī)排氣噪聲的有效手段。傳統(tǒng)柴油機(jī)的排氣消聲器由于其消聲量與排氣背壓的矛盾導(dǎo)致其綜合性能較差。因此,研發(fā)一種既消聲性能好又排氣背壓低的新型消聲器具有重要意義。研究發(fā)現(xiàn),氣流速度是一個決定消聲器綜合性能好壞的關(guān)鍵性因素。為此,課題組提出了一種分流氣體對沖降速的消聲原理,并基于該原理試制了消聲單元。針對分流氣體對沖消聲單元,本文利用理論計(jì)算、數(shù)值模擬和試驗(yàn)分析的方法對其內(nèi)部氣流速度的變化規(guī)律進(jìn)行了分析。首先設(shè)計(jì)了消聲器試驗(yàn)系統(tǒng),在此基礎(chǔ)上,驗(yàn)證了氣流速度對抗性消聲器性能影響的重要性;分析了分流氣體對沖消聲單元?dú)饬鲗_過程的速度變化規(guī)律以及對沖降速與內(nèi)流場的關(guān)系;研究了消聲單元結(jié)構(gòu)參數(shù)對氣流速度影響規(guī)律,并采用正交試驗(yàn)法確定了消聲單元的較優(yōu)結(jié)構(gòu)參數(shù)組合;最后對分流氣體對沖消聲單元的性能進(jìn)行了綜合研究。得出以下主要結(jié)論:(1)建立了氣流對沖過程氣體微團(tuán)縱向速度變化的數(shù)學(xué)模型。利用Matlab軟件對氣體微團(tuán)在對沖過程中的速度變化進(jìn)行了分析,結(jié)果顯示,兩股氣流以一定速度對沖后,在對沖面附近縱向速度迅速降低到零。(2)對消聲單元?dú)饬鲗_過程的速度變化規(guī)律進(jìn)行了分析。結(jié)果發(fā)現(xiàn),兩股氣流對沖后,主流由縱向流動轉(zhuǎn)變?yōu)闄M向流動,同時(shí)在對沖面附近形成了幾處速度較低的渦流,整體速度大小得到了一定的衰減;在對沖區(qū)域中心處,縱向氣流速度降到了最低,平均降幅為65%。在兩個對沖區(qū)域連線的中間位置,橫向氣流受到二次對沖的作用,速度幾乎降到了零。(3)對氣流對沖與壓力場的關(guān)系進(jìn)行了試驗(yàn)研究。試驗(yàn)表明,兩股氣流對沖造成了一定的壓力損失,占整個消聲單元壓力損失的50%左右,對沖過程中流體的平均阻力系數(shù)為0.91。(4)采用正交試驗(yàn)法分析了消聲單元四種結(jié)構(gòu)參數(shù)(內(nèi)腔直徑、對沖孔形狀、對沖孔中心距、尾管過渡圓弧)對平均氣流速度的影響規(guī)律,得到了其對消聲單元?dú)饬魉俣鹊挠绊懼鞔雾樞?從主到次依次為內(nèi)腔直徑、對沖孔形狀、尾管過渡圓弧半徑、對沖孔中心距。(5)對分流氣體對沖消聲單元的性能進(jìn)行了綜合研究,并與CG25型單缸柴油機(jī)原裝排氣消聲器進(jìn)行了對比。結(jié)果顯示,在中低頻段分流氣體對沖消聲單元的平均傳遞損失提高了 30.8%,平均插入損失提高了 30%;當(dāng)入口速度為30m/s時(shí),分流氣體對沖消聲單元的壓力損失降低了 16.8%;在相同入口速度條件下,分流氣體對沖消聲單元的湍動能分布范圍小于原裝消聲器,而二者的湍動能最大值基本相等,在一定程度上反映了分流氣體對沖消聲單元的再生噪聲小于原裝消聲器。
[Abstract]:The installation of exhaust muffler is an effective means to control the exhaust noise of diesel engine. The comprehensive performance of the exhaust muffler of traditional diesel engine is poor due to the contradiction between its muffling quantity and exhaust back pressure. It is of great significance to develop a new type of muffler with good muffler performance and low exhaust pressure. It is found that airflow velocity is a key factor to determine the overall performance of muffler. In this paper, we put forward a kind of sound suppression principle of shunt gas hedging and reducing speed, and based on this principle, we have trial-produced the silencing unit. In this paper, we use theoretical calculation to counter the noise reduction unit of shunt gas. Numerical simulation and experimental analysis are used to analyze the variation of the internal airflow velocity. Firstly, the muffler test system is designed, and the importance of the influence of the airflow velocity on the performance of the resistant muffler is verified. In this paper, the law of velocity variation and the relationship between the velocity reduction and the flow field in the process of the gas flow hedging are analyzed, and the influence of the structural parameters of the silencing unit on the velocity of the airflow is studied. The optimum structural parameter combination of the noise attenuation unit is determined by orthogonal test. The main conclusions are as follows: 1) the mathematical model of longitudinal velocity variation of gas microclusters in the process of gas flow hedging is established. The variation of velocity during punching is analyzed. The results show that the longitudinal velocity of the two streams is reduced rapidly to zero near the hedge surface after the two streams are hedged at a certain speed.) the law of the velocity variation of the silencing unit is analyzed. The results show that after the two air currents are hedged, the velocity changes are analyzed. The main stream changes from longitudinal flow to transverse flow, and at the same time, several low velocity eddies are formed near the hedge surface, and the overall velocity decreases to a certain extent, while at the center of the hedge area, the longitudinal flow velocity decreases to the lowest. In the middle of the line between the two hedges, the transverse flow is subjected to a secondary hedge, and the velocity drops to almost zero. 3) the relationship between the flow hedging and the pressure field is studied experimentally. The pressure loss is about 50% of the pressure loss of the whole silencing unit. The average resistance coefficient of the fluid in the hedging process is 0.91.4.The four structural parameters (the diameter of the inner cavity) of the silencing unit are analyzed by orthogonal test. For the shape of punching hole, the center distance of punching hole and the transition arc of tail tube), the influence law of the average airflow velocity is obtained, and the primary and secondary order of the influence on the airflow velocity of the silencing unit is obtained. The order from the main to the secondary is the diameter of the inner cavity, and the shape of the punching hole. In this paper, a comprehensive study on the performance of the shunt gas counteracting unit is carried out with the radius of the tailpipe transition arc and the center distance of the punching hole. The performance of the unit is compared with the original exhaust muffler of the CG25 type single-cylinder diesel engine. The results show that, The average transmission loss and average insertion loss of the counteracting unit in the low and medium frequency range are increased by 30.8 and 30, respectively; when the inlet velocity is 30 m / s, the average insertion loss is increased by 30 m / s. Under the same inlet velocity, the distribution range of turbulent kinetic energy of the shunt gas hedge silencing unit is smaller than that of the original muffler, and the maximum turbulent kinetic energy of the two units is basically equal. To some extent, it reflects that the regenerative noise of the shunt gas counteracting unit is less than that of the original muffler.
【學(xué)位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S218.5
【相似文獻(xiàn)】
相關(guān)期刊論文 前4條
1 方詩倫;湯楚宙;羅海峰;;下吹氣流速度對雜交水稻授粉分布的影響[J];湖南農(nóng)業(yè)大學(xué)學(xué)報(bào)(自然科學(xué)版);2014年04期
2 程菊芬;清潔級動物實(shí)驗(yàn)室環(huán)境檢測[J];中國養(yǎng)兔;2001年03期
3 李振山;地形起伏對氣流速度影響的風(fēng)洞實(shí)驗(yàn)研究[J];水土保持研究;1999年04期
4 周良富;張曉辛;呂曉蘭;丁素明;;圓盤霧化器風(fēng)力性能數(shù)值模擬與試驗(yàn)[J];農(nóng)業(yè)機(jī)械學(xué)報(bào);2012年10期
相關(guān)會議論文 前1條
1 楊純?nèi)A;卜維平;;流力冷卻塔的原理特性與節(jié)水節(jié)能問題探討[A];全國暖通空調(diào)制冷1998年學(xué)術(shù)年會資料集（1）[C];1998年
相關(guān)博士學(xué)位論文 前1條
1 蘇赫;柴油機(jī)分流氣體對沖排氣消聲單元?dú)饬魉俣确治鲅芯縖D];內(nèi)蒙古農(nóng)業(yè)大學(xué);2017年
，
本文編號：1574100
本文鏈接：http://sikaile.net/shoufeilunwen/nykjbs/1574100.html
本文選題：柴油機(jī) 切入點(diǎn)：消聲器 出處：《內(nèi)蒙古農(nóng)業(yè)大學(xué)》2017年博士論文 論文類型：學(xué)位論文
【摘要】：安裝排氣消聲器是控制柴油機(jī)排氣噪聲的有效手段。傳統(tǒng)柴油機(jī)的排氣消聲器由于其消聲量與排氣背壓的矛盾導(dǎo)致其綜合性能較差。因此,研發(fā)一種既消聲性能好又排氣背壓低的新型消聲器具有重要意義。研究發(fā)現(xiàn),氣流速度是一個決定消聲器綜合性能好壞的關(guān)鍵性因素。為此,課題組提出了一種分流氣體對沖降速的消聲原理,并基于該原理試制了消聲單元。針對分流氣體對沖消聲單元,本文利用理論計(jì)算、數(shù)值模擬和試驗(yàn)分析的方法對其內(nèi)部氣流速度的變化規(guī)律進(jìn)行了分析。首先設(shè)計(jì)了消聲器試驗(yàn)系統(tǒng),在此基礎(chǔ)上,驗(yàn)證了氣流速度對抗性消聲器性能影響的重要性;分析了分流氣體對沖消聲單元?dú)饬鲗_過程的速度變化規(guī)律以及對沖降速與內(nèi)流場的關(guān)系;研究了消聲單元結(jié)構(gòu)參數(shù)對氣流速度影響規(guī)律,并采用正交試驗(yàn)法確定了消聲單元的較優(yōu)結(jié)構(gòu)參數(shù)組合;最后對分流氣體對沖消聲單元的性能進(jìn)行了綜合研究。得出以下主要結(jié)論:(1)建立了氣流對沖過程氣體微團(tuán)縱向速度變化的數(shù)學(xué)模型。利用Matlab軟件對氣體微團(tuán)在對沖過程中的速度變化進(jìn)行了分析,結(jié)果顯示,兩股氣流以一定速度對沖后,在對沖面附近縱向速度迅速降低到零。(2)對消聲單元?dú)饬鲗_過程的速度變化規(guī)律進(jìn)行了分析。結(jié)果發(fā)現(xiàn),兩股氣流對沖后,主流由縱向流動轉(zhuǎn)變?yōu)闄M向流動,同時(shí)在對沖面附近形成了幾處速度較低的渦流,整體速度大小得到了一定的衰減;在對沖區(qū)域中心處,縱向氣流速度降到了最低,平均降幅為65%。在兩個對沖區(qū)域連線的中間位置,橫向氣流受到二次對沖的作用,速度幾乎降到了零。(3)對氣流對沖與壓力場的關(guān)系進(jìn)行了試驗(yàn)研究。試驗(yàn)表明,兩股氣流對沖造成了一定的壓力損失,占整個消聲單元壓力損失的50%左右,對沖過程中流體的平均阻力系數(shù)為0.91。(4)采用正交試驗(yàn)法分析了消聲單元四種結(jié)構(gòu)參數(shù)(內(nèi)腔直徑、對沖孔形狀、對沖孔中心距、尾管過渡圓弧)對平均氣流速度的影響規(guī)律,得到了其對消聲單元?dú)饬魉俣鹊挠绊懼鞔雾樞?從主到次依次為內(nèi)腔直徑、對沖孔形狀、尾管過渡圓弧半徑、對沖孔中心距。(5)對分流氣體對沖消聲單元的性能進(jìn)行了綜合研究,并與CG25型單缸柴油機(jī)原裝排氣消聲器進(jìn)行了對比。結(jié)果顯示,在中低頻段分流氣體對沖消聲單元的平均傳遞損失提高了 30.8%,平均插入損失提高了 30%;當(dāng)入口速度為30m/s時(shí),分流氣體對沖消聲單元的壓力損失降低了 16.8%;在相同入口速度條件下,分流氣體對沖消聲單元的湍動能分布范圍小于原裝消聲器,而二者的湍動能最大值基本相等,在一定程度上反映了分流氣體對沖消聲單元的再生噪聲小于原裝消聲器。
[Abstract]:The installation of exhaust muffler is an effective means to control the exhaust noise of diesel engine. The comprehensive performance of the exhaust muffler of traditional diesel engine is poor due to the contradiction between its muffling quantity and exhaust back pressure. It is of great significance to develop a new type of muffler with good muffler performance and low exhaust pressure. It is found that airflow velocity is a key factor to determine the overall performance of muffler. In this paper, we put forward a kind of sound suppression principle of shunt gas hedging and reducing speed, and based on this principle, we have trial-produced the silencing unit. In this paper, we use theoretical calculation to counter the noise reduction unit of shunt gas. Numerical simulation and experimental analysis are used to analyze the variation of the internal airflow velocity. Firstly, the muffler test system is designed, and the importance of the influence of the airflow velocity on the performance of the resistant muffler is verified. In this paper, the law of velocity variation and the relationship between the velocity reduction and the flow field in the process of the gas flow hedging are analyzed, and the influence of the structural parameters of the silencing unit on the velocity of the airflow is studied. The optimum structural parameter combination of the noise attenuation unit is determined by orthogonal test. The main conclusions are as follows: 1) the mathematical model of longitudinal velocity variation of gas microclusters in the process of gas flow hedging is established. The variation of velocity during punching is analyzed. The results show that the longitudinal velocity of the two streams is reduced rapidly to zero near the hedge surface after the two streams are hedged at a certain speed.) the law of the velocity variation of the silencing unit is analyzed. The results show that after the two air currents are hedged, the velocity changes are analyzed. The main stream changes from longitudinal flow to transverse flow, and at the same time, several low velocity eddies are formed near the hedge surface, and the overall velocity decreases to a certain extent, while at the center of the hedge area, the longitudinal flow velocity decreases to the lowest. In the middle of the line between the two hedges, the transverse flow is subjected to a secondary hedge, and the velocity drops to almost zero. 3) the relationship between the flow hedging and the pressure field is studied experimentally. The pressure loss is about 50% of the pressure loss of the whole silencing unit. The average resistance coefficient of the fluid in the hedging process is 0.91.4.The four structural parameters (the diameter of the inner cavity) of the silencing unit are analyzed by orthogonal test. For the shape of punching hole, the center distance of punching hole and the transition arc of tail tube), the influence law of the average airflow velocity is obtained, and the primary and secondary order of the influence on the airflow velocity of the silencing unit is obtained. The order from the main to the secondary is the diameter of the inner cavity, and the shape of the punching hole. In this paper, a comprehensive study on the performance of the shunt gas counteracting unit is carried out with the radius of the tailpipe transition arc and the center distance of the punching hole. The performance of the unit is compared with the original exhaust muffler of the CG25 type single-cylinder diesel engine. The results show that, The average transmission loss and average insertion loss of the counteracting unit in the low and medium frequency range are increased by 30.8 and 30, respectively; when the inlet velocity is 30 m / s, the average insertion loss is increased by 30 m / s. Under the same inlet velocity, the distribution range of turbulent kinetic energy of the shunt gas hedge silencing unit is smaller than that of the original muffler, and the maximum turbulent kinetic energy of the two units is basically equal. To some extent, it reflects that the regenerative noise of the shunt gas counteracting unit is less than that of the original muffler.
【學(xué)位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S218.5
【相似文獻(xiàn)】
相關(guān)期刊論文 前4條
1 方詩倫;湯楚宙;羅海峰;;下吹氣流速度對雜交水稻授粉分布的影響[J];湖南農(nóng)業(yè)大學(xué)學(xué)報(bào)(自然科學(xué)版);2014年04期
2 程菊芬;清潔級動物實(shí)驗(yàn)室環(huán)境檢測[J];中國養(yǎng)兔;2001年03期
3 李振山;地形起伏對氣流速度影響的風(fēng)洞實(shí)驗(yàn)研究[J];水土保持研究;1999年04期
4 周良富;張曉辛;呂曉蘭;丁素明;;圓盤霧化器風(fēng)力性能數(shù)值模擬與試驗(yàn)[J];農(nóng)業(yè)機(jī)械學(xué)報(bào);2012年10期
相關(guān)會議論文 前1條
1 楊純?nèi)A;卜維平;;流力冷卻塔的原理特性與節(jié)水節(jié)能問題探討[A];全國暖通空調(diào)制冷1998年學(xué)術(shù)年會資料集（1）[C];1998年
相關(guān)博士學(xué)位論文 前1條
1 蘇赫;柴油機(jī)分流氣體對沖排氣消聲單元?dú)饬魉俣确治鲅芯縖D];內(nèi)蒙古農(nóng)業(yè)大學(xué);2017年
，本文編號：1574100
本文鏈接：http://sikaile.net/shoufeilunwen/nykjbs/1574100.html
最近更新
教材專著
