测量排气流量的内锥流量计数值模拟与实验

Numerical and Experimental Study on V-cone Flowmeter for the Vehicle Exhaust Gas Flow Measurement

为了保证碳平衡法测量实车油耗的精度,对油耗测量系统中的内锥流量计进行了特性研究。用Fluent软件对内锥流量计进行了数值模拟,研究不同等效直径比、前后锥角、有无连接支撑杆等几何参数以及雷诺数对内锥流量计永久压力损失和流出系数的影响规律;将设计的两种内锥流量计与标准临界文丘里管组进行了对比验证实验,并以文丘里管实测值为参考值,得出了计算流出系数的拟合公式,将此拟合公式作为流量计算模型。结果表明数值模拟计算与实验验证的一致性较好,设计的内锥流量计具有较高精度和稳定性,适用于汽车排气流量测量。

In order to accurately test the fuel consumption with carbon balance method, a series ot characteristic studies were carried out on V-cone flowmeters for exhaust flow measurement. The Fluent was used to simulate the flow of V-cone flowmeter, and the influence of key factors on the permanent pressure loss and discharge coefficient such as different values of equivalent diameter ratio, fore-and-aft V-cone and Reynolds number etc. were studied. Then, two V-cone flowmeters were designed and comparison experiment with Venturi tubes was carried out . Finally, two fitting formulas which were deduced from the Venturi tubes＇ test were used as calculation models. The result of the experiment indicates that the simulation and the experiment have strong consistency and the flowmeters are of great accuracy and stability, and they can be used to measure the vehicle exhaust gas flow.