超临界RP-3管内换热特性实验

Experimental investigation on heat transfer of supercritical RP-3

关键词:  燃气轮机  超临界  加热  对流  传热系数  结焦

Key words:  Gas turbine  Supercriticality  Heating  Convection  Heat transfer coefficient  Coke deposition+

摘要:

实验研究了超临界RP-3管内换热特性。实验段为2100mm长、外径2.2mm,内径1.8mm不锈钢管(材质:1Cr18Ni9Ti)。RP-3在5MPa压力下流经该实验管,采用近似等热流加热方式将其从127℃加热至427℃。通过测量0min,20min,30min,45min和60min时管外壁和流体温度得到管内对流换热系数hin沿流向分布、结焦对管内传热系数Kin影响。研究结果表明:在远离临界点的亚临界区域,hin随着RP-3温度上升逐渐增大;在近临界区管内对流换热系数迅速增加;而进入超临界区域后,hin保持在1.8×104W/(m·℃)附近;结焦对管内传热影响显著,Kin随结焦增多逐渐降低,而降幅逐渐减小。

Abstract:

Experiments are performed to investigate heat transfer characteristics of supercritical RP-3. The test section is a 2 100 mm long, 2.2 mm O.D., 1.8 mm I.D., stainless steel tube (manufactured with 1Cr18Ni9Ti). RP-3 is heated electrically up to 427℃ from 127℃ as it flows through the test tube. The variation of convective heat transfer coefficient(hin) along the tube is achieved by measuring outer tube and fuel temperature at 0 min, 20 min, 30 min, 45 min and 60 min. The influence of coke deposition on heat transfer is also studied. The experimental results reveal that hin increases gradually as RP-3 temperature rises up in subcritical state, hin maintains at a constant value as it reaches to approximately 1.8×104 W/(m2·℃) for supercritical RP-3. The heat transfer is enhanced significantly at near-critical zone. The coke deposition has great effects on RP-3 heat transfer, which decreases as coke accumulated on tube surface.