切向/螺旋进气道稳流实验与数值仿真

为了研究内燃机进气道及缸内的流动规律,并验证数值仿真在内燃机中流动的可行性,对典型的内燃机切向/螺旋组合进气系统的三维流场进行了稳流实验,并用商业软件Fluent数值仿真了实验条件下进气道及缸内流场.由文中给出的算法计算的涡流比及流量系数与实验结果具有较好的一致性.通过仿真流场分析发现,随着气流逐渐远离气缸盖,垂直于气缸轴向的截面上速度分布越规整,越易形成单一方向的旋涡.研究结果表明,数值仿真可以较准确地得到直观的进气道和缸内流场,补充了稳流实验.

Test and Numerical Simulation of Tangent/Helical Intake Duct

In order to study the flow in the intake ducts and cylinder and validate numerical simulation method,steady flow test and numerical simulation for the three-dimensional flow field in combination intake system with tangent intake duct and helical intake duct had been carried out.By employing a new method brought forward to calculate the intensity of the swirl and flow coefficient from velocity field computed by compute fluid dynamic(CFD) simulation,numerical prediction had been compared with test results.Good agreement between numerical results and experimental data is demonstrated.It is found that when the airflow flows far away from valves and meanwhile the flow pattern in the cylinder gradually becomes uniform and form a vortex.It is also show that the CFD simulation could get more information on flow field and hence provide a strong basis for design of inlet duct.