Abstract In this research, a novel structure of methanol cracking device was designed for methanol decomposition by using internal combustion (IC) engine exhaust heat. To evaluate and optimize its performance, the flow and heat transfer processes in methanol cracking device were investigated by computational fluid dynamics (CFD) simulation. The results show that methanol flow rate has important effects on the pressure loss, temperature distribution and heat flux. In general, the flow velocity and pressure in methanol cracking device are not well-proportioned and it results in the asymmetrical distributions of temperature and heat transfer coefficient. The maximum heat transfer coefficient is close to 100 W/(m2·K) while the minimum almost equals to zero because of flow stagnant zone. The average heat transfer coefficient increases as methanol flow rate rises, and it reaches to 51.63 W/(m2·K) at the methanol flow rate of 0.06 kg/s. When methanol flow rate increases from 0.03 kg/s to 0.06 kg/s, the average outlet temperature decreases from 615 K to 560 K and meets the requirements for methanol cracking reaction. All these indicate that the designed methanol cracking device can be used for IC engine exhaust heat cracking methanol, and also provide theoretical guidance for further optimizing the geometry structure.

中文翻译：

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新型内燃机废热回收甲醇裂解装置流动传热过程数值研究

摘要 本研究设计了一种新型结构的甲醇裂解装置，利用内燃机尾气热分解甲醇。为了评估和优化其性能，通过计算流体动力学 (CFD) 模拟研究了甲醇裂解装置中的流动和传热过程。结果表明，甲醇流量对压力损失、温度分布和热通量有重要影响。甲醇裂解装置中的流速和压力一般不均衡，导致温度和传热系数分布不对称。最大传热系数接近100 W/(m2·K)，而最小传热系数几乎为零，因为存在滞流区。平均传热系数随着甲醇流量的增加而增加，在甲醇流量为0.06 kg/s时达到51.63 W/(m2·K)。当甲醇流速从0.03 kg/s增加到0.06 kg/s时，平均出口温度从615 K降低到560 K，满足甲醇裂解反应的要求。表明所设计的甲醇裂解装置可用于内燃机废气热裂解甲醇，也为进一步优化几何结构提供理论指导。