【作者】 李凌波；

【导师】 石程名；

【作者基本信息】 重庆大学 ， 热能工程， 2008， 硕士

【摘要】 气-液之间的传热采用液体在管内,气体在带肋片的管外流动的肋片管直接间壁式换热是一种组合很好的传热方法。但因这种间壁式换热器的换热流体仅一壁之隔,调节壁温的能力有限,不能适应需要大幅度调节壁温的传热场合。采用径向热管可人为增加气液之间的传热热阻。可较大幅度调节换热面的温度,避免在换热壁面上结水露或酸露,防止换热器堵灰或腐蚀。本文对三种不同偏心率径向热管（偏心率为0、23%和34%）进行了传热性能实验,工质为水。研究了热流密度、热管工作温度和充液率对传热性能的影响。将实验中不同偏心率径向热管对热流密度变化的响应时间进行比较,结果表明偏心率为23%和34%径向热管较偏心率为0（即同心）径向热管对热流密度变化的响应速度快,更容易快速调节壁温的优点。对实验数据进行回归分析,得到不同偏心率径向热管的当量内热阻关系式。偏心率为0的径向热管当量内热阻R =3839 .1t_v^-0.233q_w^-1.237Ω^-0.4996;偏心率为23%径向热管的当量内热阻R = 21763.58t_v^-0.39q_w^-1.344Ω^-0.279;偏心率为34%径向热管当量内热阻R = 39576.58t_v^-0.541q_w^-1.344Ω^-0.436。通过对回归关系式的显著性检验说明该关系式能正确地反映这些热管的传热性能。更多还原

【Abstract】 The gas-liquid heat transfer process, which the gas flows through finned tube outer wall while the liquid flows in the tube, is a kind of excellent heat transfer mode. In this heat exchanger, only the tube wall separates the cool and warm fluids, results that the wall temperature can not be largely adjusted. So when the wall temperature needs to be largely changed, this heat exchanger is not suitable anymore. The thermal resistance between the gas and liquid can be subjectively increased by longitude heat pipe, and the wall temperature can be lager scale adjusted to avoid water or acid coagulation and further ash accumulation or corrosion.Three pieces of heat pipes with different eccentricities （0, 23% and 34%） are tested in present paper, and the working fluid is water. The effect of heat flux, operation temperature and the liquid full ratio on heat transfer is carefully evaluated.The corresponding times to heat flux of three pieces of heat pipes with different eccentricities are recorded and compared. The results reveal that the heat pipes with eccentricity of 23% and 34% are more sensitive than the heat pipes with 0% eccentricity, and the former two heat pipes can more rapidly than the latter in adjusting wall temperature.The unit thermal resistance of three pieces of heat pipes with different eccentricities are regressed as follows: for 0% eccentricity, R =3839.1t_v^-0.233q_w^-1.237Ω^-0.4996; for 23% eccentricity, R = 21763.58t_v^-0.39q_w^-1.344Ω^-0.279; for 34% eccentricity, R = 39576.58t_v^-0.541q_w^-1.344Ω^-0.436. These relation equations are proved to be correct by test of statistical significance.更多还原