本文選題：膨脹機(jī)　切入點(diǎn)：螺旋槽道　出處：《北京工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：單螺桿膨脹機(jī)是一種利用低溫小規(guī)模熱源進(jìn)行發(fā)電的動(dòng)力設(shè)備,可在較低溫度熱源下獲得相對較高的發(fā)電效率,在余熱回收利用工程中具有良好的應(yīng)用前景。目前對單螺桿膨脹機(jī)的研究主要側(cè)重在加工和性能方面,缺少對單螺桿膨脹機(jī)螺桿螺旋槽道內(nèi)兩相流流動(dòng)特性的研究,而單螺桿膨脹機(jī)螺桿螺旋槽道內(nèi)氣液兩相流的流動(dòng)特性正是影響其工作效率的重要因素之一。因此,提出對螺桿螺旋槽道內(nèi)氣液兩相流流動(dòng)特性進(jìn)行實(shí)驗(yàn)研究。實(shí)驗(yàn)中采用有機(jī)玻璃材質(zhì)加工出直徑分別為117mm、155mm兩種尺寸的透明螺桿。螺桿中的螺旋槽道是一種截面形狀不規(guī)則的三維螺旋槽道,實(shí)驗(yàn)以水和空氣為工質(zhì)對該螺桿螺旋槽道內(nèi)氣液兩相流流動(dòng)特性展開研究。借助高速攝像儀,采用背光成像的可視化方法對單螺桿螺旋槽道內(nèi)流型結(jié)構(gòu)進(jìn)行觀測,得到了不同工況條件下,不同周角位置處氣液兩相流型及各流型的特征。實(shí)驗(yàn)結(jié)果表明:螺桿螺旋槽道內(nèi)主要存在泡狀流、間歇流和環(huán)狀流等流型;各流型的特征受工況條件和周角位置的影響而各不相同,即使同一工況下,同一流型在各周角位置的特征也不相同。根據(jù)實(shí)驗(yàn)觀測結(jié)果,繪制了三個(gè)周角位置處的流型圖,并對各流型之間的轉(zhuǎn)換特性進(jìn)行分析,給出了泡狀流向間歇流轉(zhuǎn)變、環(huán)狀流向間歇流轉(zhuǎn)變的準(zhǔn)則關(guān)系式。由于氣液兩相流的壓降和壓差波動(dòng)信息可以反映通道內(nèi)兩相流動(dòng)的狀況,研究這些參數(shù)的特性對實(shí)現(xiàn)兩相流動(dòng)監(jiān)測與控制具有重要意義,對兩相流動(dòng)系統(tǒng)的設(shè)計(jì)和運(yùn)行等問題也具有指導(dǎo)意義。因此,對螺桿螺旋槽道內(nèi)氣液兩相流在進(jìn)、出口處的壓降進(jìn)行實(shí)驗(yàn)研究,對不同流型時(shí)的壓差波動(dòng)信號進(jìn)行統(tǒng)計(jì)分析,提取壓差波動(dòng)信號的概率密度函數(shù)特征和功率譜密度函數(shù)特征,為提高單螺桿膨脹機(jī)系統(tǒng)的運(yùn)行效率提供基礎(chǔ)指導(dǎo)。
[Abstract]:Single screw expander is a kind of power equipment which uses low temperature and small scale heat source to generate electricity, which can obtain relatively high power generation efficiency under lower temperature heat source. It has a good application prospect in waste heat recovery and utilization engineering. At present, the research on single screw expander is mainly focused on processing and performance, but the study on two-phase flow characteristics in screw groove of single screw expander is lacking. The flow characteristics of gas-liquid two-phase flow in the spiral channel of a single screw expander are one of the important factors affecting its working efficiency. The flow characteristics of gas-liquid two-phase flow in screw spiral channel were studied experimentally. In the experiment, transparent screw with diameter of 117mm / 155mm and diameter of 117mm / 155mm were fabricated by using organic glass material. The spiral groove in screw is a cross-section. Irregular three-dimensional spiral groove, The flow characteristics of gas-liquid two-phase flow in the spiral channel of the screw were studied with water and air as the working medium. The flow pattern of the spiral channel of the single screw was observed by means of high speed camera and visual method of backlight imaging. The characteristics of gas-liquid two-phase flow patterns and flow patterns at different circumferential angles are obtained under different working conditions. The experimental results show that there are mainly bubbly flow, intermittent flow and annular flow in screw screw spiral channel. The characteristics of each flow pattern are different from each other by the working conditions and the circumferential position. Even under the same working condition, the characteristics of the same flow pattern at each circumferential angle are different. According to the experimental observation results, the flow pattern at the three circumferential positions is plotted. The conversion characteristics between different flow patterns are analyzed, and the bubbly flow flow transition is given. Because the pressure drop and pressure fluctuation information of gas-liquid two-phase flow can reflect the condition of two-phase flow in the channel, it is important to study the characteristics of these parameters to realize the monitoring and control of two-phase flow. Therefore, the pressure drop at inlet and outlet of gas-liquid two-phase flow in screw spiral channel is studied experimentally, and the fluctuation signals of pressure difference in different flow patterns are analyzed statistically. The characteristics of probability density function and power spectrum density function of differential pressure fluctuation signal are extracted to provide basic guidance for improving the operation efficiency of single-screw expander system.
【學(xué)位授予單位】：北京工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O359.1;TK115

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 邵莉;劉利民;苑偉;韓吉田;陳常念;;R134a臥式螺旋管內(nèi)沸騰兩相流型與傳熱特性實(shí)驗(yàn)研究[J];原子能科學(xué)技術(shù);2013年03期

，

本文編號：1611384