摘要
该文在中低热流密度、质量流速的条件下,针对超超临界循环流化床锅炉的水冷壁管进行流动传热特性的试验研究。试验中使用材质为15Gr Mo G、外径和壁厚为φ35mm×5.67mm的六头内螺纹管,试验压力P为23-32MPa、质量流速G为600-1200kg/（m2·s）、热流密度q为200～510k W/m2。该文展示试验中获取的管壁温度的分布规律;拟合出可以用于工程实际的传热和阻力系数的公式;用六个传热系数公式对试验数据进行评估;探讨管内传热强化和减弱的机理。试验结果表明：压力和热流密度的变化对壁温的影响主要集中在焓值大于2400k J/kg的区域;质量流速的增大可以延迟传热恶化;浮升力对传热的影响集中在流体拟临界温度之前;相对于质量流速,热流密度和压力的变化对摩擦压降和阻力系数的影响更为显著。
Under the condition of low heat flux and mass flux, an experimental investigation on flow and heat transfer characteristics of an ultra-supercritical circulating fluidized bed （CFB） boiler water wall tube had been conducted. The material of the six-head rifled tube used in the test was 15GrMoG. The diameter and wall thickness was Ф35mm × 5.67mm. The range of pressure was from 23MPa to 32MPa, mass flux was from 600kg/（m2.s） to 1200kg/（m2.s）, and heat flux was from 200kW/m2 to 510kW/m2. In this paper, the wall temperature distribution obtained in the test had been exhibited. The empirical correlations of heat transfer coefficient and frictional resistance coefficient were derived. Six heat transfer coefficient correlations evaluated against the test data. The mechanism of heat transfer enhancement and heat transfer deterioration were analyzed. The results show that the effects of pressure and heat flux on wall temperature are significant within the region of high enthalpy （enthalpy〉2400kJ/kg）. When the mass flux increases, the heat transfer deterioration of the tube will be delayed. The effect of buoyancy is significant when the temperature is less than the pseudo-critical temperature. The effects of the heat flux and pressure on frictional pressure drop are more dominant in the supercritical pressure regions.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2018年第2期373-382,共10页
Proceedings of the CSEE
基金
国家重点研发计划(2016YFB0600201)~~
关键词
超超临界
循环流化床锅炉
内螺纹管
传热特性
阻力特性
ultra-supercritical
circulating fluidized bed （CFB） boiler
rifled tube
heat transfer characteristics
resistance characteristics
