Experimental characterization of the turbulent intake jet in an engine flow bench
Experimental characterization of the turbulent intake jet in an engine flow bench
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DOI：
10.1007/s00348-023-03640-9
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发表时间：
2023-04
影响因子：
2.4
通讯作者：
C. Welch;L. Illmann;M. Schmidt;B. Böhm
中科院分区：
文献类型：
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作者：
C. Welch;L. Illmann;M. Schmidt;B. Böhm
利用空气流动试验台对光学可接近内燃机的湍流进气流动进行建模，以降低发动机流动中固有变量数量的复杂性。通过拆卸活塞并引入新的光学接触外壳和排气通道，流动试验台设计模拟了进气门下游区域的发动机流动，并提供了测量和计算在动态发动机的不稳定环境中难以或不可能获得的量的可能性。通过高速粒子图像测速仪在对称平面和气门平面上获得的流动台速度数据，与汽车发动机在进气压力为bar，转速为°CA(压缩上止点前的曲轴转角)时的基本工作状态的数据进行了比较，从对应的气门升程为°CA的静止气门开始，然后是移动的气门。对增大质量流量的进气射流湍流的分析表明，仅在质量流量百分比的情况下，射流在频率为赫兹的情况下有相干拍打。阀杆的旋涡脱落频率估计在-Hz范围内，这表明相干喷流扑动与通过气门间隙的加速后的旋涡脱落之间可能存在联系。通过综合分析，本研究为内燃机进气流动提供了有价值的验证数据和洞察力。
The turbulent intake flow of an optically accessible internal combustion engine is modeled using an air flow bench to reduce the complexity in the number of variables inherent within engine flows. By removing the piston and introducing a new optically accessible housing and outlet channel, the flow bench design simulates engine flows in the region just downstream of the intake valves and offers the possibility to measure and calculate quantities that would be difficult or impossible to obtain in the unsteady environment of a dynamic engine. Velocity data obtained via high-speed particle image velocimetry of the flow bench in the symmetry and valve planes are compared with data from a base operating condition of the motored engine at an intake pressure ofbar and a speed ofrpm at°CA (crank-angle-degrees before compression top dead center), beginning with stationary valves at the corresponding valve lift of°CA, then with moving valves. Analysis of the intake jet turbulence for increasing mass flow rates reveals a coherent flapping of the jet at a frequency ofHz for only the% mass flow rate case. The vortex shedding frequency of the valve stem is estimated to being in the range of–Hz, indicating a possible link between the coherent jet flapping and the vortex shedding surviving the acceleration through the valve gap. Through comprehensive analysis, this study provides valuable validation data and insight into the intake flows of internal combustion engines.