Volumetric intake flow measurements of an IC engine using magnetic resonance velocimetry
Volumetric intake flow measurements of an IC engine using magnetic resonance velocimetry
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DOI：
10.1007/s00348-014-1724-6
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发表时间：
2014-05
影响因子：
2.4
通讯作者：
D. Freudenhammer;E. Baum;B. Peterson;B. Böhm;B. Jung;S. Grundmann
中科院分区：
文献类型：
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作者：
D. Freudenhammer;E. Baum;B. Peterson;B. Böhm;B. Jung;S. Grundmann
磁共振测速 (MRV) 测量在单缸光学发动机的 1:1 比例模型中进行，以研究气流感应期间进气口和气缸几何形状内的体积流量。该模型是光学 IC 发动机的稳定流水模拟，具有固定的气门升程 mm，以模拟曲柄角 bTDC 处的进气流。该设置类似于稳流发动机测试台配置。 MRV 测量通过在光学引擎对称平面内执行的相位平均粒子图像测速 (PIV) 测量进行验证。 MRV 和 PIV 测量之间实验操作参数的差异得到了很好的解决。 MRV 和 PIV 测量值的比较通过归一化平均速度分量分布图进行论证，并在气缸室的上部（即毫米）表现出极好的一致性。 MRV 测量进一步用于分析 3D 发动机域内的整体平均体积流量。测量用于描述环形流进入气缸室时的 3D 上溢和下溢行为。在 3D 空间中识别流动特征，例如延伸到气缸中的环形射流状流动、它们对大范围缸内流动运动的影响以及流动再循环区域。对整个阀帘周边的入口流速进行分析，以量化进入气缸的质量流量百分比。与底流相关的再循环区域可将局部质量流量降低高达 50%。在进气歧管和气缸室内的 3D 空间中进一步分析再循环区域。建议这样的再循环区域对汽缸充气填充和汽缸内流动模式的变化具有重大影响。 MRV 被认为是一种重要的诊断工具，用于了解发动机几何形状内的体积进气流量，并且可能适合评估由于进气几何形状修改而导致的流量变化。
Magnetic resonance velocimetry (MRV) measurements are performed in a 1:1 scale model of a single-cylinder optical engine to investigate the volumetric flow within the intake and cylinder geometry during flow induction. The model is a steady flow water analogue of the optical IC-engine with a fixed valve lift ofmm to simulate the induction flow at crank-anglebTDC. This setup resembles a steady flow engine test bench configuration. MRV measurements are validated with phase-averaged particle image velocimetry (PIV) measurements performed within the symmetry plane of the optical engine. Differences in experimental operating parameters between MRV and PIV measurements are well addressed. Comparison of MRV and PIV measurements is demonstrated using normalized mean velocity component profiles and showed excellent agreement in the upper portion of the cylinder chamber (i.e.,mm). MRV measurements are further used to analyze the ensemble average volumetric flow within the 3D engine domain. Measurements are used to describe the 3Doverflowandunderflowbehavior as the annular flow enters the cylinder chamber. Flow features such as the annular jet-like flows extending into the cylinder, their influence on large-scale in-cylinder flow motion, as well as flow recirculation zones are identified in 3D space. Inlet flow velocities are analyzed around the entire valve curtain perimeter to quantify percent mass flow rate entering the cylinder. Recirculation zones associated with the underflow are shown to reduce local mass flow rates up to 50 %. Recirculation zones are further analyzed in 3D space within the intake manifold and cylinder chamber. It is suggested that such recirculation zones can have large implications on cylinder charge filling and variations of the in-cylinder flow pattern. MRV is revealed to be an important diagnostic tool used to understand the volumetric induction flow within engine geometries and is potentially suited to evaluate flow changes due to intake geometry modifications.