氢燃料电池汽车在风洞试验中的氢泄漏扩散分析

Analysis of Hydrogen Leakage and Diffusion in Vehicle Wind Tunnel Based on CFD

摘要:

采用数值模拟方法，研究氢燃料电池汽车在发生氢泄漏情况下，氢气在风洞内部的流动扩散规律与分布情况。当风洞模拟汽车以80 km/h行驶工况时，车底部泄漏的氢气紧贴着汽车表面向后移动进入汽车的尾流区，氢气浓度随着离汽车尾部距离的增加而降低。从收集口进入流道内的氢气集中在中、底部，具有明显的浓度梯度，经过风扇区后变得均匀；10 s后车底泄漏的氢气又重新回到试验段，与车底正在泄漏的氢气汇合，造成整个区域氢气浓度的持续升高。由于风洞流道拐角导流片的存在，流道内测的氢气浓度升高的更快。当风洞模拟汽车怠速工况时，泄漏的氢气大多在试验段内流动扩散，流道内几乎检测不到氢气。受试验段内气流扰动的影响，汽车两侧的氢气呈现出不对称分布，顶部的氢气集中在车左侧。根据数值模拟结果给出了氢浓度传感器的安装位置建议。

关键词:汽车风洞;氢燃料电池汽车（HFCVs）;氢泄漏;数值模拟

Abstract:

With the rapid development of hydrogen fuel cell vehicles （HFCVs）， it is possible for hydrogen fuel cell vehicles to be tested in wind tunnels. In this paper， the flow diffusion law and distribution of hydrogen in wind tunnel under the condition of HFCV leak were studied by numerical simulation. When the wind tunnel simulates the driving condition of the HFCV at 80 km/h， the leaking hydrogen moves against the surface of the car and into the wake area. The hydrogen concentration decreases with increasing distance from the car. The hydrogen entering the flow channel from the collecting port is concentrated in the middle and bottom， with an obvious concentration gradient， and becomes uniform after passing through the fan section. After 10s， the hydrogen leaking from the bottom of the car returned to the test section and merged with the hydrogen leaking from the car， resulting in a continuous increase in the concentration of hydrogen in the entire area. The concentration of hydrogen inboard path increases faster than outboard path due to the deflectors at the corner of the channel. When the wind tunnel simulates the idling condition， the leaking hydrogen mostly diffuses in the test section and almost no hydrogen is detected in the flow channel. Affected by airflow disturbance in the test section， the hydrogen on two sides of the vehicle presents an unsymmetrical distribution， the hydrogen at the top is concentrated on the left side of the HFCV.Finally， according to the numerical simulation results， the installation position of the hydrogen sensors is suggested.

Key words:wind tunnel;hydrogen fuel cell vehicles (HFCVs);hydrogen leakage;numerical simulation