A Three-Dimensional Unsteady CFD Model of Compressor Stability
A Three-Dimensional Unsteady CFD Model of Compressor Stability
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DOI：
10.1115/gt2006-90040
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发表时间：
2013-07
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通讯作者：
R. Chima
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作者：
R. Chima
摘要三维非定常CFD代码CSTALL已被开发并用于研究压气机稳定性。代码解决了整个环和所有叶片的欧拉方程。叶栅转动、损失和偏差采用体积力项进行建模，这需要叶栅之间站点的输入数据。输入数据是使用一个单独的Navier-Stokes湍流分析代码在失速附近的一个工作点上计算的，并使用整体特性图按比例缩放到其他工作点。CSTALL在二维通流模式下运行，用于非常快速地计算工作图和估计失速点。NASA 35级的压比特性计算值与实验值吻合较好，考虑进气道径向畸变时的计算结果显示了预期的射程损失。CSTALL也在三维模式下运行，以研究进气道周向畸变。计算的35级120度畸变屏的运行图显示出射程损失和压力上升。非定常计算表明，旋转失速与两部分跨度失速细胞。本文详细地叙述了体积力公式，并对计算结果进行了检验，最后给出了对程序的观察结果。NOMENCLATUREB阻塞无粘总能量F转动的体积力f损失的体积力，p，T，s焓，压力，温度，熵离心力，科里奥利力，与阻塞源项垂直方向修正质量守恒矢量时间V速度柱坐标柱速度分量相对气流、叶片和偏离角差气流方向网格密度通过气流时间尺度体积力矢量体积力比例函数偏离的转向函数叶栅角速度损失系数下标0停滞状态1，2上游、下游LE、TE前缘、后缘转向、熵、偏离、参考点网格出口、节流阀下游下标相对速度稳定状态引言压气机失速和喘振可能对飞机造成灾难性后果，然而，对这些现象的预测仍然是科学界尚未解决的主要问题之一。已经开发了许多失速模型，对这种现象有了一些了解，但很少有模型能够预测失速的开始，除了对整个压气机进行全面的计算流体动力学（CFD）分析，这超出了本文的范围。现有的模型从旋转失速或压缩系统稳定性的分析模型到压缩系统的二维或三维CFD模型。所有的模型都需要输入一些有关压缩机性能的信息，
ABSTRACTA three-dimensional unsteady CFD code called CSTALL has beendeveloped and used to investigate compressor stability. The codesolved the Euler equations through the entire annulus and all bladerows. Blade row turning, losses, and deviation were modeled usingbody force terms which required input data at stations between bladerows. The input data was calculated using a separate Navier-Stokesturbomachinery analysis code run at one operating point near stall,and was scaled to other operating points using overall characteristicmaps. No information about the stalled characteristic was used.CSTALL was run in a 2-D throughflow mode for very fast calcula-tions of operating maps and estimation of stall points. Calculated pres-sure ratio characteristics for NASA stage 35 agreed well withexperimental data, and results with inlet radial distortion showed theexpected loss of range. CSTALL was also run in a 3-D mode to inves-tigate inlet circumferential distortion. Calculated operating maps forstage 35 with 120 degree distortion screens showed a loss in range andpressure rise. Unsteady calculations showed rotating stall with twopart-span stall cells. The paper describes the body force formulation indetail, examines the computed results, and concludes with observa-tions about the code.NOMENCLATUREb blockageinviscid fluxese total energyF body force for turningf body force for lossh, p, T, s enthalpy, pressure, temperature, entropyCentrifugal, Coriolis, and blockage source termsm meridional directionalcorrected mass flowq vector of conserved variablest timeV velocitycylindrical coordinatescylindrical velocity componentsrelative flow, blade, and deviation anglesdifferencestreamwise grid directiondensitythroughflow time scalebody force vectorbody force scaling functionturning function for deviationblade row angular velocityloss coefficientSubscripts0 stagnation state1,2 upstream, downstreamLE, TE leading edge, trailing edgeturning, entropy, deviation, reference pointgrid exit, downstream of throttleSuperscriptsrelative velocityss steady stateINTRODUCTIONCompressor stall and surge can have catastrophic consequences inaircraft, yet prediction of these phenomena remains as one of themajor unsolved problems in turbomachinery. Many models of stallthat give some insight into the phenomena have been developed butfew models are capable of predicting stall onset, except perhaps forfull computational fluid dynamic (CFD) analysis of the entire com-pressor which is beyond the scope of this paper. Existing modelsrange from analytic models of rotating stall or compression systemstability to 2-Dor 3-DCFD models of compression systems. All mod-els require input of some information about compressor performance,E,G,HKm˙