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

【摘要】：單螺桿膨脹機是一種利用低溫小規(guī)模熱源進行發(fā)電的動力設備,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用前景。目前對單螺桿膨脹機的研究主要側重在加工和性能方面,缺少對單螺桿膨脹機螺桿螺旋槽道內兩相流流動特性的研究,而單螺桿膨脹機螺桿螺旋槽道內氣液兩相流的流動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氣液兩相流流動特性進行實驗研究。實驗中采用有機玻璃材質加工出直徑分別為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,實驗以水和空氣為工質對該螺桿螺旋槽道內氣液兩相流流動特性展開研究。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流型結構進行觀測,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。實驗結果表明:螺桿螺旋槽道內主要存在泡狀流、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)實驗觀測結果,繪制了三個周角位置處的流型圖,并對各流型之間的轉換特性進行分析,給出了泡狀流向間歇流轉變、環(huán)狀流向間歇流轉變的準則關系式。由于氣液兩相流的壓降和壓差波動信息可以反映通道內兩相流動的狀況,研究這些參數(shù)的特性對實現(xiàn)兩相流動監(jiān)測與控制具有重要意義,對兩相流動系統(tǒng)的設計和運行等問題也具有指導意義。因此,對螺桿螺旋槽道內氣液兩相流在進、出口處的壓降進行實驗研究,對不同流型時的壓差波動信號進行統(tǒng)計分析,提取壓差波動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系統(tǒng)的運行效率提供基礎指導。
[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.
【學位授予單位】：北京工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：O359.1;TK115

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相關期刊論文 前1條

1 邵莉;劉利民;苑偉;韓吉田;陳常念;;R134a臥式螺旋管內沸騰兩相流型與傳熱特性實驗研究[J];原子能科學技術;2013年03期

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本文編號：1611384