離心壓氣機(jī)非軸對(duì)稱流動(dòng)特性及進(jìn)氣畸變對(duì)內(nèi)部流場(chǎng)的影響研究
發(fā)布時(shí)間：2019-07-08 18:25
【摘要】：離心壓氣機(jī)作為小型燃?xì)廨啓C(jī)及渦輪增壓器的核心部件,被廣泛應(yīng)用于軍事、民用領(lǐng)域。壓氣機(jī)蝸殼周向非對(duì)稱的幾何結(jié)構(gòu)使得蝸殼內(nèi)部靜壓周向分布不均勻,從而導(dǎo)致非設(shè)計(jì)工況下壓氣機(jī)性能下降。另一方面,離心壓氣機(jī)設(shè)計(jì)一般是在均勻進(jìn)氣的前提下進(jìn)行,而實(shí)際使用中由于受整機(jī)空間布置等限制,壓氣機(jī)進(jìn)氣常采用不同形式的彎扭管道,而彎扭管道的導(dǎo)流作用使葉輪進(jìn)口出現(xiàn)復(fù)雜的總壓和旋渦畸變,這不但影響壓氣機(jī)的性能和穩(wěn)定工作范圍,還會(huì)引起壓氣機(jī)的可靠性和穩(wěn)定性發(fā)生變化。本文以J90-2型離心壓氣機(jī)為研究對(duì)象,通過實(shí)驗(yàn)和數(shù)值模擬的方法研究了壓氣機(jī)的非軸對(duì)稱流動(dòng)特性及進(jìn)氣畸變對(duì)其內(nèi)部流場(chǎng)的影響。主要研究目的在于:一是通過分析離心壓氣機(jī)蝸殼內(nèi)部高靜壓區(qū)域產(chǎn)生的擾動(dòng)壓力波動(dòng)沿葉輪槽道逆向傳播的過程,揭示壓氣機(jī)非軸對(duì)稱流動(dòng)特性的形成機(jī)理,并闡明由此引起的內(nèi)部流場(chǎng)變化以及對(duì)葉輪進(jìn)出口氣流參數(shù)、葉片載荷的影響機(jī)制。二是闡明彎扭管道出口截面上二次流場(chǎng)結(jié)構(gòu)、總壓和旋渦畸變特性隨管道扭轉(zhuǎn)角度的演化規(guī)律。定量確定不同彎扭管道出口截面上的旋渦強(qiáng)度、旋渦方向、旋渦對(duì)數(shù)等描述畸變流場(chǎng)細(xì)節(jié)的參數(shù)存在的差別。三是研究葉輪進(jìn)口旋渦畸變引起的離心壓氣機(jī)性能變化及其原因。發(fā)現(xiàn)葉輪進(jìn)口氣流旋渦畸變指數(shù)與葉輪進(jìn)氣條件間的關(guān)聯(lián)關(guān)系,分析進(jìn)氣畸變與蝸殼靜壓畸變的耦合特征,關(guān)注不同旋渦畸變進(jìn)氣時(shí)壓氣機(jī)內(nèi)部流場(chǎng)的變化特點(diǎn)。基于上述研究目的,本文通過對(duì)不同彎扭管道進(jìn)行設(shè)計(jì),建立了帶有直管以及典型的彎扭進(jìn)氣管道的壓氣機(jī)幾何模型,并選用NUMECA軟件展開了數(shù)值研究工作。與此同時(shí),實(shí)驗(yàn)研究在不同的壓氣機(jī)轉(zhuǎn)速和流量工況下開展,實(shí)驗(yàn)中分別在進(jìn)口接入直管和上述典型的彎扭管道,同時(shí)測(cè)量壓氣機(jī)內(nèi)部壁面關(guān)鍵點(diǎn)的靜壓變化。通過壓氣機(jī)直管進(jìn)氣下的實(shí)驗(yàn)驗(yàn)證了數(shù)值計(jì)算的可靠性,同時(shí)獲得彎扭管道進(jìn)氣引起壓氣機(jī)性能和測(cè)點(diǎn)靜壓的變化規(guī)律。通過數(shù)值計(jì)算得到一系列彎扭管道進(jìn)氣下的總壓以及旋渦畸變形式,在對(duì)氣流畸變程度量化描述的基礎(chǔ)上總結(jié)出畸變隨流量變化的特點(diǎn)。研究發(fā)現(xiàn),改變彎扭管道的扭轉(zhuǎn)角度可以在管道出口得到較為典型的旋渦結(jié)構(gòu):當(dāng)扭轉(zhuǎn)角度為0°和180°時(shí),旋渦結(jié)構(gòu)對(duì)應(yīng)孿生渦的形式;當(dāng)扭轉(zhuǎn)角度為90°,旋渦近似呈現(xiàn)團(tuán)渦的特征。研究表明,與葉輪進(jìn)口形成的孿生渦相比,近似團(tuán)渦的旋渦形式對(duì)壓氣機(jī)性能的影響有顯著差異,當(dāng)近似團(tuán)渦的旋渦方向與葉輪轉(zhuǎn)動(dòng)方向相同時(shí),壓氣機(jī)性能下降程度最大;而旋渦方向與葉輪轉(zhuǎn)動(dòng)方向相反時(shí),對(duì)壓氣機(jī)性能的影響最小。在非設(shè)計(jì)流量工況下,對(duì)于離心壓氣機(jī)的非軸對(duì)稱流動(dòng)特性研究方面,實(shí)驗(yàn)和數(shù)值模擬證實(shí)了蝸殼靜壓對(duì)壓氣機(jī)輪緣及進(jìn)口靜壓分布產(chǎn)生的影響。通過葉片槽道靜壓變化時(shí)空?qǐng)D展示了蝸殼高靜壓擾動(dòng)壓力波動(dòng)在葉輪流場(chǎng)中逆向傳播的途徑,發(fā)現(xiàn)大流量工況下蝸殼高靜壓擾動(dòng)壓力波可以傳播到葉輪進(jìn)口,而小流量工況下,蝸殼靜壓擾動(dòng)壓力波強(qiáng)度較弱,對(duì)葉輪進(jìn)口幾乎不產(chǎn)生影響。通過對(duì)比葉輪進(jìn)出口氣流參數(shù)的變化情況和葉輪槽道流量分配形式,表明小流量工況的影響較大。同時(shí),進(jìn)一步分析了非軸對(duì)稱流動(dòng)對(duì)葉片載荷分布和波動(dòng)形式的影響,得到葉片載荷波動(dòng)的頻譜特性。大流量工況下,主葉片表面載荷波動(dòng)主要受基頻影響,而小流量工況下主要受2倍頻的影響。在典型彎扭管道進(jìn)氣對(duì)壓氣機(jī)性能和內(nèi)部流動(dòng)的影響研究方面,明確了葉輪進(jìn)口旋渦畸變是影響壓氣機(jī)性能的主要因素,全面闡述了不同葉高氣流旋渦角度、旋渦強(qiáng)度與相對(duì)氣流角之間的關(guān)聯(lián)關(guān)系,研究發(fā)現(xiàn):葉輪進(jìn)口氣流旋渦在不同葉高位置上的旋渦角度和強(qiáng)度改變了葉片前緣相對(duì)氣流角,進(jìn)而對(duì)進(jìn)氣攻角產(chǎn)生明顯影響,這是造成壓氣機(jī)性能變化的根本原因。葉輪進(jìn)口的旋渦畸變引起的正攻角增大使葉尖間隙泄漏流的發(fā)生位置向葉片前緣移動(dòng),間隙泄漏流強(qiáng)度也隨之增大;正攻角減小或出現(xiàn)負(fù)攻角時(shí),葉尖間隙泄漏流發(fā)生的位置向葉片尾緣移動(dòng)。葉片槽道內(nèi)流過的空氣流量受進(jìn)口畸變流場(chǎng)結(jié)構(gòu)和蝸殼內(nèi)部靜壓分布的雙重因素影響,葉輪進(jìn)口的孿生旋渦形式明顯擴(kuò)大了葉輪出口周向靜壓梯度,使葉輪各槽道流量分配的不平衡性顯著增加;而近似團(tuán)渦的旋渦形式對(duì)葉輪各槽道流量分配影響較小。另外,當(dāng)葉輪進(jìn)口氣流對(duì)渦結(jié)構(gòu)的對(duì)稱度較高時(shí),對(duì)葉片載荷波動(dòng)的影響較小,而旋渦形式近似成團(tuán)渦時(shí),對(duì)葉片載荷波動(dòng)影響較大。
文內(nèi)圖片：
圖片說明：壓氣機(jī)輪緣測(cè)點(diǎn)測(cè)點(diǎn)靜壓變化
[Abstract]:As the core component of small gas turbine and turbocharger, centrifugal compressor is widely used in military and civil fields. The asymmetric geometry of the compressor volute is such that the static pressure in the spiral case is not uniform in the circumferential direction, resulting in a decrease in the performance of the compressor under the non-design condition. on the other hand, the design of the centrifugal compressor is generally carried out on the premise of uniform air intake, and in the actual use, due to the limitation of the space arrangement of the whole machine, the air inlet of the compressor often adopts a different form of the twisted pipe, The flow-guiding effect of the bent-and-torsion pipe makes the inlet of the impeller complex total pressure and vortex distortion, which not only affects the performance and the stable operating range of the compressor, but also causes the reliability and stability of the compressor to change. In this paper, a J90-2 centrifugal compressor is used as the research object, and the influence of the non-axisymmetric flow characteristics and the intake distortion on the internal flow field of the compressor is studied by means of experimental and numerical simulation. The main research aim is to reveal the formation mechanism of the non-axisymmetric flow characteristics of the compressor by analyzing the disturbance pressure fluctuation generated by the high static pressure region in the volute of the centrifugal compressor, And the influence mechanism of the flow parameters and the blade load on the inlet and outlet of the impeller. The second is to clarify the evolution of the secondary flow field structure, total pressure and vortex distortion in the outlet section of the twisted pipe. The differences in the parameters of the detail of the distortion flow field such as the vortex strength, the vortex direction, the vortex log and the like on the outlet cross-section of the different bent-and-twisted pipe are quantitatively determined. Thirdly, the performance of the centrifugal compressor caused by the vortex distortion of the impeller is studied. The relationship between the vortex distortion index of the inlet air flow and the air inlet condition of the impeller is found, and the coupling characteristics of the inlet distortion and the static pressure distortion of the spiral case are analyzed. Based on the above research, this paper establishes a compressor geometry model with a straight pipe and a typical twisted-and-twisted air inlet duct through the design of different bent-and-twisted pipes, and a numerical study is carried out using the NUMECA software. At the same time, the experimental research is carried out under different compressor speed and flow conditions, and the static pressure changes of key points in the inner wall of the compressor are measured at the same time in the experiment. The reliability of the numerical calculation is verified by the experiment under the air inlet of the compressor straight pipe, and the variation law of the compressor performance and the static pressure of the measuring point is obtained. The total pressure and the form of the vortex distortion are obtained by numerical calculation, and the characteristics of the distortion with the flow rate are summarized on the basis of the description of the degree of distortion of the air flow. It is found that changing the twist angle of the twisted pipe can get a typical vortex structure at the outlet of the pipe. When the twist angle is 0 擄 and 180 擄, the vortex structure corresponds to the form of the twin vortex. When the twist angle is 90 擄, the vortex approximation presents the characteristic of the group vortex. The results show that, compared with the twin vortex formed by the inlet of the impeller, the vortex form of the approximate group vortex has a significant difference in the performance of the compressor, and when the vortex direction of the approximate group vortex is the same as the rotation direction of the impeller, the performance of the compressor is the greatest; And the vortex direction is the same as the rotation direction of the impeller, and the effect on the performance of the compressor is minimized. In the non-designed flow condition, for the non-axisymmetric flow characteristics of the centrifugal compressor, the influence of the static pressure of the volute on the compressor wheel rim and the inlet static pressure distribution is verified by the experimental and numerical simulation. in that case of large flow condition, the pressure wave of the high static pressure disturbance of the spiral case can be transmitted to the inlet of the impeller, and under the condition of small flow, The pressure wave intensity of the static pressure disturbance of the spiral case is weak, which has little effect on the inlet of the impeller. By comparing the change of the inlet and outlet flow parameters of the impeller and the flow distribution of the impeller channel, it is indicated that the influence of the small flow condition is large. At the same time, the influence of the non-axisymmetric flow on the blade load distribution and the wave form is further analyzed, and the spectral characteristic of the blade load fluctuation is obtained. Under the condition of large flow, the main blade surface load fluctuation is mainly affected by the fundamental frequency, and under the condition of small flow, the influence of frequency doubling is mainly affected. In that study of the effect of inlet on the performance and internal flow of the compressor, it is clear that the vortex distortion of the inlet of the impeller is the main factor that affect the performance of the compressor. The results show that the vortex angle and the intensity of the vortex in the high position of the inlet of the impeller change the relative air flow angle of the leading edge of the blade, and then the angle of attack of the intake air is obviously affected, which is the root cause of the change of the performance of the compressor. The positive angle of attack caused by the vortex distortion of the impeller inlet increases the position of the tip clearance leakage flow to the leading edge of the blade, and the strength of the gap leakage flow is also increased; when the positive attack angle is reduced or the negative attack angle is present, the position of the tip clearance leakage flow is moved toward the trailing edge of the blade. The air flow in the blade channel is affected by the inlet distorted flow field structure and the static pressure distribution in the spiral case. The twin vortex form of the impeller inlet obviously increases the circumferential static pressure gradient of the impeller outlet, so that the imbalance of the flow distribution of each channel of the impeller is obviously increased; And the vortex form of the approximate group vortex has less influence on the flow distribution of each channel of the impeller. In addition, when the flow of the impeller inlet to the vortex structure is higher, the influence of the blade load fluctuation is small, and the effect of the vortex form on the blade load fluctuation is large.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TH452
，
本文編號(hào)：2511786
文內(nèi)圖片：
圖片說明：壓氣機(jī)輪緣測(cè)點(diǎn)測(cè)點(diǎn)靜壓變化
[Abstract]:As the core component of small gas turbine and turbocharger, centrifugal compressor is widely used in military and civil fields. The asymmetric geometry of the compressor volute is such that the static pressure in the spiral case is not uniform in the circumferential direction, resulting in a decrease in the performance of the compressor under the non-design condition. on the other hand, the design of the centrifugal compressor is generally carried out on the premise of uniform air intake, and in the actual use, due to the limitation of the space arrangement of the whole machine, the air inlet of the compressor often adopts a different form of the twisted pipe, The flow-guiding effect of the bent-and-torsion pipe makes the inlet of the impeller complex total pressure and vortex distortion, which not only affects the performance and the stable operating range of the compressor, but also causes the reliability and stability of the compressor to change. In this paper, a J90-2 centrifugal compressor is used as the research object, and the influence of the non-axisymmetric flow characteristics and the intake distortion on the internal flow field of the compressor is studied by means of experimental and numerical simulation. The main research aim is to reveal the formation mechanism of the non-axisymmetric flow characteristics of the compressor by analyzing the disturbance pressure fluctuation generated by the high static pressure region in the volute of the centrifugal compressor, And the influence mechanism of the flow parameters and the blade load on the inlet and outlet of the impeller. The second is to clarify the evolution of the secondary flow field structure, total pressure and vortex distortion in the outlet section of the twisted pipe. The differences in the parameters of the detail of the distortion flow field such as the vortex strength, the vortex direction, the vortex log and the like on the outlet cross-section of the different bent-and-twisted pipe are quantitatively determined. Thirdly, the performance of the centrifugal compressor caused by the vortex distortion of the impeller is studied. The relationship between the vortex distortion index of the inlet air flow and the air inlet condition of the impeller is found, and the coupling characteristics of the inlet distortion and the static pressure distortion of the spiral case are analyzed. Based on the above research, this paper establishes a compressor geometry model with a straight pipe and a typical twisted-and-twisted air inlet duct through the design of different bent-and-twisted pipes, and a numerical study is carried out using the NUMECA software. At the same time, the experimental research is carried out under different compressor speed and flow conditions, and the static pressure changes of key points in the inner wall of the compressor are measured at the same time in the experiment. The reliability of the numerical calculation is verified by the experiment under the air inlet of the compressor straight pipe, and the variation law of the compressor performance and the static pressure of the measuring point is obtained. The total pressure and the form of the vortex distortion are obtained by numerical calculation, and the characteristics of the distortion with the flow rate are summarized on the basis of the description of the degree of distortion of the air flow. It is found that changing the twist angle of the twisted pipe can get a typical vortex structure at the outlet of the pipe. When the twist angle is 0 擄 and 180 擄, the vortex structure corresponds to the form of the twin vortex. When the twist angle is 90 擄, the vortex approximation presents the characteristic of the group vortex. The results show that, compared with the twin vortex formed by the inlet of the impeller, the vortex form of the approximate group vortex has a significant difference in the performance of the compressor, and when the vortex direction of the approximate group vortex is the same as the rotation direction of the impeller, the performance of the compressor is the greatest; And the vortex direction is the same as the rotation direction of the impeller, and the effect on the performance of the compressor is minimized. In the non-designed flow condition, for the non-axisymmetric flow characteristics of the centrifugal compressor, the influence of the static pressure of the volute on the compressor wheel rim and the inlet static pressure distribution is verified by the experimental and numerical simulation. in that case of large flow condition, the pressure wave of the high static pressure disturbance of the spiral case can be transmitted to the inlet of the impeller, and under the condition of small flow, The pressure wave intensity of the static pressure disturbance of the spiral case is weak, which has little effect on the inlet of the impeller. By comparing the change of the inlet and outlet flow parameters of the impeller and the flow distribution of the impeller channel, it is indicated that the influence of the small flow condition is large. At the same time, the influence of the non-axisymmetric flow on the blade load distribution and the wave form is further analyzed, and the spectral characteristic of the blade load fluctuation is obtained. Under the condition of large flow, the main blade surface load fluctuation is mainly affected by the fundamental frequency, and under the condition of small flow, the influence of frequency doubling is mainly affected. In that study of the effect of inlet on the performance and internal flow of the compressor, it is clear that the vortex distortion of the inlet of the impeller is the main factor that affect the performance of the compressor. The results show that the vortex angle and the intensity of the vortex in the high position of the inlet of the impeller change the relative air flow angle of the leading edge of the blade, and then the angle of attack of the intake air is obviously affected, which is the root cause of the change of the performance of the compressor. The positive angle of attack caused by the vortex distortion of the impeller inlet increases the position of the tip clearance leakage flow to the leading edge of the blade, and the strength of the gap leakage flow is also increased; when the positive attack angle is reduced or the negative attack angle is present, the position of the tip clearance leakage flow is moved toward the trailing edge of the blade. The air flow in the blade channel is affected by the inlet distorted flow field structure and the static pressure distribution in the spiral case. The twin vortex form of the impeller inlet obviously increases the circumferential static pressure gradient of the impeller outlet, so that the imbalance of the flow distribution of each channel of the impeller is obviously increased; And the vortex form of the approximate group vortex has less influence on the flow distribution of each channel of the impeller. In addition, when the flow of the impeller inlet to the vortex structure is higher, the influence of the blade load fluctuation is small, and the effect of the vortex form on the blade load fluctuation is large.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TH452
，
本文編號(hào)：2511786
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