共查询到18条相似文献,搜索用时 125 毫秒
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离心压气机弯管进口畸变非定常特性 总被引:3,自引:0,他引:3
采用数值模拟计算的方法研究了90°弯管对涡轮增压器装配的离心压气机进口流场产生的畸变,比较了两种不同轴向位置弯管所致的进口畸变对压气机性能的影响,并对压气机内部的三维非定常流动进行了频域分析.结果表明,弯管畸变对离心压气机性能的恶化程度与弯管所在位置有关,距离叶轮进口较远的弯管影响较大.畸变引起压气机性能在大流量时有明显降低,在小流量时性能恶化程度较小.弯管畸变导致叶轮进口前的压力脉动增强,大流量时改变了叶轮流道上游和叶顶间隙内的压力频谱结构,显著提高了转子基频的扰动强度.同时畸变也造成了叶片振动和蜗壳舌部噪声的恶化,在小流量工况下的作用更加明显. 相似文献
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《内燃机学报》2016,(5)
蜗壳通常被设计成螺旋状结构,其几何结构的周向不对称诱发蜗壳内部流场周向分布不均匀现象,会对压气机内部流场造成显著影响.采用试验和数值结合的方法,对两种流量工况下离心压气机内部的非轴对称流动特性进行研究.结果表明:压气机轮缘静压在周向上的分布具有与蜗壳内部相同特征的非轴对称形式;下游流场畸变在向上游逆向传播过程中对上游的影响逐渐减弱;叶轮出口轮缘周向的高压区传播至叶轮进口时,与叶轮出口高压区的周向位置存在相位差.在不同流量工况下,轮缘周向静压分布不均导致叶顶间隙泄漏流在周向的分布存在差异.在小流量工况下,泄漏流量呈现先减小后增大再减小的波动分布;在大流量工况下,泄漏流量呈现先增大后持续减小分布. 相似文献
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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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为了研究进气畸变对压气机的工作特性以及稳定性的影响,以NASA Stage35型跨音速轴流压气机为研究对象,采用全通道计算模型对不同畸变程度和不同畸变分布形式条件下压气机的工作特性及内部流场变化规律进行数值模拟研究。结果表明:随着进气畸变度的不断增加,压气机的峰值效率逐渐下降,由畸变所引起的总压损失在压气机内部流道中逐渐扩大;在保持畸变度和畸变区域总面积不变的条件下,畸变区的分散程度对压气机在峰值效率点附近的工作特性影响较小,但随着畸变分布区分散程度的逐渐增加,压气机的稳定裕度有所提高,压气机内部流道中的总压损失和熵增也有所降低。 相似文献
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针对某型柴油机增压器压气机,基于整级全通道数值模拟和正交试验设计方法,研究了自循环机匣处理实现高亚声速压气机扩稳增效的潜力。结果表明:自循环机匣能够在提高设计点气动性能的前提下推迟失稳,但会牺牲堵塞流量。压气机的失稳和堵塞流量分别与叶片前缘及叶片扩压器中的堵塞程度相关。小流量侧自循环机匣通过抽吸叶轮叶顶附近低能流体,缓解堵塞,推迟失稳。但在大流量侧自循环机匣的喷射效应会增大扩压器进口攻角,加剧扩压器叶片流动分离,减小堵塞流量。抽吸效应与喷射效应强度均取决于抽吸槽的位置和宽度,压气机稳定性和堵塞流量与抽吸槽参数的变化基本呈负相关。自循环机匣对气动性能的影响包含两方面:在抽吸槽前,经回流槽流出的流体与主流的掺混及其产生的进口畸变将带来额外的效率和压比损失,适当减小回流槽角度可以降低该损失;在抽吸槽下游,得益于抽吸效应对叶顶流动状态的改善,压气机抽吸槽附近及下游高熵区减小,做功能力增强,气动损失大幅降低。在上述两方面共同影响下,压气机设计点气动性能最终得以提高。 相似文献
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废气涡轮增压器压气机两种进气预旋及其性能研究 总被引:1,自引:0,他引:1
作者扼要地叙述两种进气预旋的工作原理以及它在压气机性能调节中的意义。文中以GJ11和45GP802等型增压器为例,阐明它们在引入进气预旋流场后,其压气机性能所出现的变化及其对柴油机匹配性能的影响。 相似文献
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《International Journal of Hydrogen Energy》2020,45(19):11276-11286
Centrifugal compressors are one of the most important auxiliary components in polymer electrolyte membrane fuel cell vehicles, which tend to operate at a narrow area with low specific speed. Here, the optimal design goals of centrifugal compressors are investigated on the basis of a lumped model for fuel cell systems. A three-dimensional multi-objective and multi-point aerodynamic optimization and data mining method for centrifugal compressors named ODM is presented via integrating a multi-island genetic algorithm, Reynolds-Average Navier-Stokes solver technique and self-organization map based data mining technique. Data mining indicates that compressor geometry would move to a small inlet diameter ratio and a narrow region of the outlet width ratio. Based on the optimization results, a centrifugal compressor for 100 kW fuel cell stack is manufactured. The experimental results show that the improvement of isentropic efficiency near low mass flow has been achieved, which indicates that the proposed ODM is effective in the performance improvement of centrifugal compressors for fuel cell vehicles. 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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基于压气机分层次气动优化设计思想,结合了优化算法、CFD(计算流体力学)技术与压气机气动设计程序,利用商业软件,建立了压气机气动优化设计平台,将气动优化设计思想融入到了压气机气动设计多个阶段,以实现压气机气动设计使性能最优化的目的.应用商业通用优化平台进行了轴流压气机一维、S2反问题气动优化设计,并采用NUMECA提供的全三维优化设计平台对压气机进行了全三维气动优化设计.计算结果表明:分层气动优化设计是提高压气机气动性能的有效手段,先进的优化算法在气动设计的各阶段都能够比传统设计手段更大限度地实现压气机性能的最优化. 相似文献
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This paper performs a numerical simulation of three-dimensional flow field in a centrifugal compressor with long inlet and outlet pipes using CFX software. By arranging virtual probes at different positions in both inlet and outlet planes, the aerodynamic performance of the centrifugal compressor is measured and compared with each other. Then effects of measuring positions on measurement results are discussed. The results show that it will generate notable measuring errors of the pressure ratio and efficiency if the inlet total pressure is measured using a single-point probe. The inlet total pressure data can be accurate when they are measured using a 3-point rake. The outlet total pressure and total temperature data can not be accurate if they are respectively measured at one circumferential position even using a multi-point rake. Increasing tangential measuring positions at the outlet is effective to improve the test accuracy. When the outlet total pressure and total temperature are respectively measured at 3 tangential positions, the data can be almost accurate. 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,通过NUMECA软件进行模拟计算,研究了前过渡段、过渡段支板和出口过渡段的气体流动损失对压气机性能的影响,并采用DFFD参数化方法和多岛遗传算法对过渡段部分进行了结构改型与气动优化设计。结果表明:相比不带过渡段的压气机模型,原型过渡段使等熵效率降低1.57%,经过对过渡段型线改进以及对过渡段支板的优化设计,优化后过渡段使等熵效率仅降低0.63%;优化后的过渡段部分气流阻塞减少、损失减小,使得高压压气机整体效率较优化前提高0.94%;经流场损失分析发现,支板段和出口扩压延长段是造成堵塞和效率降低的主要原因。 相似文献