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针对进口端壁导叶对离心压气机特性影响进行了研究,通过在试验标定仿真模型的基础上对压气机内部的流动特性进行了详细的分析,结果表明:正预旋导叶使压气机的阻塞流量和喘振流量向小流量方向偏移,有效提升离心压气机的稳定性。而负预旋导叶在流量特性上与正预旋刚好相反,使压气机特性向大流量工况偏移。进口预旋导叶的存在明显改变了叶轮进口的相对气流角,正预旋能够使得入流气流冲角变小,从而带来效率的提升。负预旋会使压气机效率特性变差。虽然端壁正预旋导叶使离心压气机堵塞流量略有降低,但是效率和稳定明显提升,并进行了实验的验证。 相似文献
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《柴油机设计与制造》1995,(3)
本文详细介绍了一种用再循环旁通槽扩大压气机工作范围的装置,该装置在压气机平台试验和柴油机台架试验上的结果表明,再循环旁通槽能够使喘振线大幅度向小流量方向移动,阻塞线向大流量方向移动。进一步的试验研究表明,再循环旁通槽在压气机进口部分造成了随流量变化而变化的预旋,这种自调节的预旋是它能够扩大压气机工作范围的主要原因之一。 相似文献
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为了降低径向进气室对压气机通流性能的影响,通过三维数值仿真对进气室的设计参数进行了研究。首先,量化评价了不同的进气室平直段子午型线对压气机进气均匀性的影响,然后对进气室支板与平直段支撑筋之间的相对角度进行了研究。研究结果表明:压气机的通流裕度对进气室平直段的型线较为敏感,需要谨慎修型以确保通流性能不会衰减;进气室平直段型线的改型主要诱发压气机进口径向叶尖的旋流畸变;而进气室支板与平直段支撑筋之间相对角度的改变对压气机进口的周向叶根畸变略有影响,支板与支撑筋重合会导致进气室的压损增加,压气机的喘振裕度略有下降,建议支板与支撑筋错开一定角度。 相似文献
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对比分析了6种不同转速下压气机性能的试验与仿真结果.在验证了ANSYS CFX软件用于压气机性能模拟分析中的可靠性后,采用数值模拟方法对3种不同叶片后弯角的叶轮进行了性能计算,得到了相关转速下的压气机特性曲线.仿真结果表明:在不改变压气机出口静压时,在一定的叶片出口角范围内,叶片后弯角的增加使两条特性曲线均向小流量方向偏移,但近喘振点边界得到了拓展,使得压气机的流量范围变得更宽;在小流量区域内,叶片后弯角的增大能够改善压气机内部流动状况,提高叶轮工作效率;而在大流量区域内,较大的叶片后弯角会使叶轮的流通特性降低,叶轮的工作效率反而会降低;适当增加叶片后弯角可以增大压气机工作范围,使压气机效率和流道内的流动均得到提高和改善. 相似文献
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《内燃机与动力装置》2020,(3)
对弯管进气的离心压气机进行数值模拟计算,通过与直管进气试验和数值模拟结果的分析对比,研究弯管对离心压气机效率的影响,分析在3种不同形式的弯管进气条件下压气机效率的变化。研究结果表明:弯管进气时压气机效率有所降低,不同形式的弯管进气对压气机效率的影响不同。在恒定转速小流量工况下,弯管与直管进气压气机效率相差较小,随着流量的增加,弯管进气与直管进气压气机效率差值逐渐增大;当转速不同时,弯管进气造成叶轮进口严重的气流不均匀流动,使效率下降,高速大流量工况效率下降最为明显,其中普通90°弯管进气效率最大降幅为7%。 相似文献
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针对V型发动机的共用单一管路对置离心压气机进口流场畸变特性进行了研究,通过台架试验测试了初始压气机性能,完成了仿真模型的标定。在此基础上分析了压气机进口流场的变化特征,分析结果表明:共用单一管路对压气机特性影响明显,造成了两侧压气机堵塞流量的降低,在大流量工况区域效率明显下降,右侧压气机恶化程度要明显高于左侧。原因在于受安装位置空间限制,喉口处畸变扩展与进口周向畸变叠加效应使得右侧压气机在周向和叶高方向的畸变程度均高于左侧压气机。进口的畸变效应会一直持续至压气机叶轮内部,使压气机性能变差。 相似文献
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为变进口参数压气机运行提供准确的喘振保护措施是压气机调节的难点之一.尽管许多压气机运行变量的变化相当容易测量,但是,测量分子量、比热和压缩性的变化却不那么容易.然而,即使这些变量难以测量,它们对压气机的运行确有影响.此外,由于相互关系复杂,一个进口参数的变化可引起其它参数变化,以致很难找出造成这些影响的直接原因.为了能够向进口参数变化的压气机提供喘振保护措施,必须研究出一种既对这些参数变化敏感,同时又能预报进口参数变化怎样影响压气机运行的方法. 相似文献
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以某型高压九级轴流压气机为研究对象,利用NUMECA软件在不同进口条件下进行变工况性能模拟计算。研究了变转速下由于进口总温、总压的改变引起的雷诺数变化对压气机性能影响。结果表明:试验条件与设计条件下的试验结果相比,进口雷诺数由1.348×10~6下降到4.318×10~5,压气机设计点折合流量比减小0.008,效率下降0.72%,喘振裕度降低了8.11%,压气机性能曲线整体向左下方移动;在一定范围内升高进口总压或降低进口总温,将改善压气机的压比、效率以及折合流量比;当雷诺数高于一定临界值后,同一转速下的压气机的效率以及折合流量比基本保持不变;当转速降低至设计转速以下时,临界雷诺数将进一步增大,雷诺数效应影响增强;雷诺数降低会导致泄漏流损失增大,径向涡损失增强,加剧叶尖区域的流动分离,此时叶尖区域的流动阻塞成为引起流动失稳与整机性能恶化的主要原因。 相似文献
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动静流道相互作用引起的非定常流动是离心式压缩机内流的主要特征,借助模态分解方法可以有效提取出该流场中相干结构,进而可以说明该动静干涉流场的主要特征。本文将动态模式分解(Dynamic Mode Decomposition,DMD)方法应用于带无叶扩压器通道的离心式压缩机流场分析中,通过对动静干涉速度场和压力场的模态提取和分析,直观揭示出动静流道中的流体运动特征。在设计流量工况下,叶轮出口叶顶间隙的流体流动和动静流道干涉效应影响了叶轮出口的速度参数和压力参数的分布。在叶轮和扩压器流道中分别出现了频率1 715和725Hz的湍流相干结构,两频率和叶轮通过频率有关。动静干涉流道中压力沿叶高方向动态规律相似,而速度场沿叶高方向波动规律存在一定的差异。该特征可以为压缩机流场测试提供参考。 相似文献
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In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, the compressed air at the exit of centrifugal compressor was re-circulated and injected to the impeller inlet by using two injection nozzles in order to suppress the surge phenomenon. The most effective circumferential position was examined to reduce the flow rate at the surge inception. Moreover, the influences of the injection on the fluctuating property of the flow field before and after the surge inception were investigated by examining the frequency of static pressure fluctuation on the wall surface and visualizing the compressor wall surface by oil-film visualization technique. 相似文献
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Investigation of a centrifugal compressor and study of the area ratio and TIP clearance effects on performance 总被引:2,自引:0,他引:2
Mahdi Nili-Ahmadabadi Ali Hajilouy-Benisi Mohammad Durali Farhad Ghadak 《热科学学报(英文版)》2008,17(4):314-323
In this research, the centrifugal compressor of a turbocharger is investigated experimentally and numerically. Performance characteristics of the compressor were obtained experimentally by measurements of rotor speed and flow parameters at the inlet and outlet of the compressor. Three dimensional flow field in the impeller and dif- fuser was analyzed numerically using a full Navier-Stokes program with SST turbulence model. The performance characteristics of the compressor were obtained numerically, which were then compared with the experimental results. The comparison shows good agreement. Furthermore, the effect of area ratio and tip clearance on the performance parameters and flow field was stud- ied numerically. The impeller area ratio was changed by cutting the impeller exit axial width from an initial value of 4.1 mm to a final value of 5.1 mm, resulting in an area ratio from 0.792 to 0.965. For the rotor with exit axial width of 4.6 mm, performance was investigated for tip clearance of 0.0, 0.5 and 1.0 mm. Results of this simula- tion at design point showed that the compressor pressure ratio peaked at an area ratio of 0.792 while the effi- ciency peaked at a higher value of area ratio of 0.878. Also the increment of the tip clearance from 0 to 1 mm resulted in 20 percent efficiency decrease. 相似文献
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A turbocharger compressor working in commercial vehicles,especially in some passenger cars,often works together with some pipes with complicated geometry as an air intake system,due to limit of available space in internal combustion engine compartments.These pipes may generate various distortions of physical parameters of the air at the inlet of the compressor and therefore the compressor aerodynamic performance deteriorates.Sometimes,the turbocharging engine fails to work at some operation points.This paper investigates the effects of various swirl distortions induced by different bending-torsional intake ducts on the aerodynamic performance of a turbocharger compressor by both 3D numerical simulations and experimental measurements.It was found that at the outlet of the pipes the different inlet ducts can generate different swirl distortions,twin vortices and bulk-like vortices with different rotating directions.Among them,the bulk-like vortices not only affect seriously the pressure distribution in the impeller domain,but also significantly deteriorate the compressor performance,especially at high flow rate region.And the rotating direction of the bulk-like vortices is also closely associated with the efficiency penalty.Besides the efficiency,the transient flow rate through a single impeller channel,or the asymmetric mass flow crossing the whole impeller,can be influenced by two disturbances.One is from the upstream bending-torsional ducts;other one is from the downstream volute. 相似文献
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Numerical analysis is conducted for the 3-dimensional impeller and vaneless diffuser of a small centrifugal com- pressor. The influence of impeller tip clearance on the flow field of the impeller is investigated. Detailed investigation on the leaking flow across the tip clearance of the impeller shows that the leaking flow rate is higher near the exit of the impeller than that near the inlet of the impeller. Based on this phenomenon, a new partially shrouded impeller is designed. The impeller is shrouded near the exit of the impeller. Numerical results show that the secondary flow region becomes smaller at the exit of the impeller. Better performance is achieved than that with the unshrouded impeller. 相似文献
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为开发高压比舰用增压器,设计了小内壳直径的压气机,并用三元流计算分析了前倾后弯叶轮中不同结构参数下的气流情况。计算使设计的结构达到预期的压气机性能。 相似文献
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遗传算法在离心压气机叶轮结构优化中的应用 总被引:1,自引:1,他引:0
利用遗传算法对离心压气机叶轮的结构进行优化设计。通过叶轮三无了流动的准正交面法计算得到离心压气机叶轮的增压经,以离心压气机叶轮增压比作为遗传算法优化设计的目标函数进行计算,获得最佳的离心压气机叶轮的结构设计参数,分析计算结果和流动曲线,验证遗传算法在离心压气机叶轮结构优化中的可行性。 相似文献