摘要
为进一步分析出湿空气作为冷却工质时气膜冷却相对于干空气气膜冷却的差异,分别通过实验与数值方法,探究了吹风比和湿空气含湿量对平板气膜冷却的影响。在实验研究中,采用红外热像仪测量靶面温度,对比分析了不同含湿量与吹风比下平板气膜冷却性能变化规律,从而得到气膜冷却效率关于吹风比与含湿量的变化关系。在数值研究中,建立了具有单个气膜孔、周期性边界条件的气膜冷却模型,利用ANSYS CFX软件数值分析了高温高压条件下的不同吹风比,不同湿空气含湿量条件下的流动与传热特性。结果表明:在实验条件下,当吹风比为0.7时,靶面冷却效率随含湿量的增加而增加;当含湿量为188.9 g/kg时,湿空气相对于干空气的靶面平均冷却效率增加量最高,约为4.8%。数值分析结果和实验吻合较好。进一步的数值分析表明,当吹风比为0.7时,气膜冷却效果最好,且吹风比处于0.3~0.7之间时,靶面的气膜冷却效果均随着含湿量的增加而增加,当吹风比大于0.7时的规律则相反。基于实验结果与数值结果拟合出靶面平均气膜冷却效率关于吹风比和含湿量的关联式,实验值和数值结果与关联式的相对误差均小于±2%。
To investigate the difference of the cooling characteristics of film cooling when moist air and dry air are used as cooling medium respectively,the experimental and numerical studies are carried and the effects of blowing ratio and humidity ratio of moist air on the film cooling performance of a flat plate are analyzed in detail.In the experimental test,the infrared camera was used to measure the temperature of the target surface.The effects of different blowing ratios and humidity ratios on the film-cooling performance were taken into consideration and the variation of film cooling efficiency with respect to blowing ratio and humidity ratio was obtained.In the numerical analysis,a film cooling model with a single film-cooling hole with periodical boundary conditions was established,and the commercial software ANSYS CFX is used to investigate the influences of the blowing ratio and the humidity ratio on film cooling performance under high temperature and high pressure condition.The experimental results show that when the blowing ratio is 0.7,the cooling performance of film cooling of the target surface improves with the increasing humidity ratio,and when the humidity is 188.9 g/kg,the average cooling efficiency of the whole target surface improves 4.8%compared to dry air cooling.The numerical study results are consistent with the experimental results.The results also show that when the blowing ratio is 0.7,the cooling performance of film cooling is optimal,and the cooling performance of film cooling of the target surface improves with the increasing humidity ratio when the blowing ratio is between 0.3 and 0.7,while the film-cooling efficiency shows a reverse trend when blowing ratio is higher than 0.7.Based on the experimental and numerical results,a correlation of film-cooling performance of the target surface in terms of the blowing ratio and the humidity ratio was proposed.The correlation has a relative error within±2%.
作者
朱华
严彪
刘雨松
李荣
李亮
ZHU Hua;YAN Biao;LIU Yusong;LI Rong;LI Liang(Institute of Turbomachinery,Xi’an Jiaotong University,Xi’an 710049,China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2022年第6期151-163,共13页
Journal of Xi'an Jiaotong University
基金
国家科技重大专项资助项目(2017-I-0009-0010)。
关键词
气膜冷却
湿空气
吹风比
含湿量
film cooling
moist air
blowing ratio
humidity ratio
