中文摘要：

自主搭建了三维粒子图像测速（3D-PIV）系统,在内燃机气道稳流试验台上测试气道流动特性.首先通过直管道流动试验以及2D-PIV试验验证了该3D-PIV系统测试结果的可靠性,随后测量了稳态试验条件下缸内流场形态,进而分析了气道的滚流强度,并与在气道稳流试验台上测得的滚流强度进行了对比.此外,研究了不同翻板位置对气道滚流强度的影响,结果表明：在气道稳流试验台上测得的滚流强度随气门升程增加呈逐渐上升趋势,而由3DPIV测得的滚流强度呈现非单调变化的特点,且在数值上高于气道试验台测量结果.使用3D-PIV可以更准确地测量滚流强度,有效地避免模拟缸套带来的摩擦损失.关闭翻板可以显著增大滚流强度,尤其在气门升程超过5,mm之后.

英文摘要：

The inlet air flow characteristics were tested on a steady flow test rig by the self-built three-dimensional particle image velocimetry （3D-PIV） system. The reliability of 3D-PIV system was firstly confirmed by a straight pipe flow experiment and a 2D-PIV experiment as well. Then, the flow field at the steady state was measured and the tum- ble ratio was analyzed based on the flow field. Also the tumble ratios obtained by the 3D-PIV and by the steady flow test rig were compared. In addition, the effect of the tumble flap in the intake port on the tumble ratio was investi- gated. The results show that the tumble ratio gained by the steady flow test rig increases with the increase of valve lift, while the tumble ratio obtained by the 3D-PIV takes a non-monotonic variation. Further, the tumble ratio from the 3D-PIV measurement is larger than that from the steady flow rig test. The measurement of tumble ratio through the 3D-PIV is more accurate and can avoid the frictional loss produced by the simulation cylinder. Closing the tumble flap can increase the tumble ratio significantly, especially when the valve lift exceeds 5 mm.