The influence of thermal stratification on hydrogen fuel flow and heat transfer in cooling channel with combining fin and dimple

• Published in: International journal of hydrogen energy 2020-03, Vol.45 (15), p.9064-9076
• Main Authors: Xie, Pengyong, Zhang, Xiaobing
• Format: Article
• Language: English
• Subjects: Combining fin and dimple structure; Cooling performance; Flow control; Flow heat transfer; Thermal stratification
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.01.026

The rockets engines combustion chamber wall suffers from high single-side heating and small cooling channel size, and this can cause serious cross-section thermal stratification and local heat transfer deterioration problem, leading to the decreasing of the flow and heat transfer efficiency and thermal protection problem. In this paper, to effectively reduce this non-uniform distribution phenomenon to enhance the flow heat transfer capacity, a new vortex generator with combing fin and dimple is proposed. The CFD software is used to numerically solve this problem and analyzed the influence of thermal stratification on hydrogen fuel flow and heat transfer. The investigation results indicate that for Rein = 42000, Nu of new dimple and fin structure improves about 94%, and the maximum heat temperature decreases 15.4% than smooth channel, while the friction factor is about 2.6 times smooth channel. The temperature non-uniform index decreases the 12.24% than smooth channel. Comparing with smooth and dimple structure, the new structure effectively reduced the thermal stratification phenomenon to improve the hydrogen fuel flow and heat transfer performance, thus the overheated structure is better protected. •The structure combining fin and dimple improves the heat transfer performance.•Non-uniform distribution problem is investigated and analyzed for new structure.•The structure combining fin and dimple weakens thermal stratification phenomenon.