燃料电池船舶舱内氢气泄漏扩散的数值模拟

利用FLUENT软件研究了不同条件下氢气在燃料电池船舶舱内的泄漏扩散规律和分布情况; 基于瞬态气体泄漏扩散模型，运用数值模拟方法，建立了船舶舱内氢气泄漏扩散的数值模型，结合影响氢气泄漏扩散的不同因素，对比分析了泄漏位置、泄漏孔径和通风条件等因素对船舶舱内氢气泄漏扩散的影响，得到了不同条件下氢气在船舶舱内的扩散规律和分布情况。分析结果表明:船舶舱内氢气泄漏扩散过程包括初始喷射、浮力上升和湍流扩散; 燃料电池舱的顶部角落和每排燃料电池发电系统之间的上部是氢气探测报警器的最佳安装位置，不同泄漏条件下氢气均在舱室顶部出现较多积聚; 不同位置和不同孔径泄漏孔的危险性在泄漏初期存在差异，但随着泄漏的持续进行，风险演变规律相近，约60 s后泄漏点附近氢气浓度均接近100%;在燃料电池舱设置防爆型排风机，采用强制抽风措施加快氢气的外排，可以显著减少氢气向其他舱室的扩散，当抽风速度为1 m·s-1时，氢气从燃料电池舱室排放到船舶舷外区域，没有氢气进入控制舱和乘客舱，可有效保障控制舱和乘客舱的安全; 强制送风会加速氢气向船艉舱、控制舱和乘客舱的扩散，增大氢气的扩散范围，加剧了氢气泄漏的危险性。 

Numerical simulation of leakage and diffusion of hydrogen in cabin of fuel cell ship

The leakage/diffusion laws and distributions of hydrogen in the compartments of a fuel cell ship under different conditions were studied by the software FLUENT. On the basis of the transient gas leakage and diffusion model, the numerical simulation method was employed to build a numerical leakage and diffusion model of hydrogen in the compartments of the ship, and the effects of different factors on hydrogen leakage and diffusion in the compartments, such as the leakage location, leakage aperture, and ventilation condition, were compared and analyzed. As a result, the diffusion patterns and distributions of hydrogen in the compartments of the ship under different conditions were obtained. Analysis results show that the leakage and diffusion process of hydrogen in a ship compartment includes the initial spray, buoyancy rise, and turbulent diffusion. The top corner of the fuel cell compartment and the upper part between each row of the fuel cell power generation system are the best locations for the hydrogen detection alarms, and hydrogen is more accumulated at the top of the compartment under different leakage conditions. The risks of different locations and different apertures of leakage holes are different at the beginning of the leakage, but the risk evolution patterns are similar with the continuation of the leakage, and the hydrogen concentration near the leakage point is close to 100% after about 60 s. The diffusion of hydrogen to other compartments can be significantly reduced by the installation of explosion-proof exhaust fans in the fuel cell compartment and the adoption of forced air extraction measures to speed up the hydrogen discharge. When the air extraction speed is 1 m·s-1, hydrogen is discharged from the fuel cell compartment to the outboard area of the ship, and no hydrogen is diffused into the control and passenger compartments. Hence, the safety of the control and passenger compartments can be effectively ensured. The diffusion of hydrogen to the stern, control, and passenger compartments, however, is accelerated by the forced air supply. Thus, the diffusion range of hydrogen is enlarged, and the risk of hydrogen leakage is aggravated.