Numerical study of heat transfer characteristics of downward supercritical kerosene flow inside circular tubes
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The heat transfer characteristics of China RP-3 aviation kerosene flowing in a vertical downward tube with an inner diameter of 4 mm under supercritical pressures are numerically studied. A ten-species surrogate model is used to calculate the thermophysical properties of kerosene and the re-normalization group (RNG) k-ε turbulent model with the enhanced wall treatment is adopted to consider the turbulent effect. The effects of mass flow rate, wall heat flux, inlet temperature, and pressure on heat transfer are investigated. The numerical results show that three types of heat transfer deterioration exist for the aviation kerosene flow. The first type of deterioration occurred at the tube inlet region and is caused by the development of the thermal boundary layer, while the other two types are observed when the inner wall temperature or the bulk fuel temperature approaches the pseudo-critical temperature. The heat transfer coefficient increases with the increasing mass flow rate and the decreasing wall heat flux, while the inlet bulk fluid temperature only influences the starting point of the heat transfer coefficient curve plotted against the bulk fluid temperature. The increase of inlet pressure can effectively eliminate the deterioration due to the small variations of properties near the pseudo-critical point at relatively high pressure. The numerical heat transfer coefficients fit well with the empirical correlations, especially at higher pressures (about 5 MPa).
Key wordsAviation kerosene Heat transfer deterioration Supercritical pressure Numerical study
1. 分析超临界航空煤油的传热恶化现象;2. 揭示超临界航空煤油传热过程中传热恶化现象与质量流量、壁面热流、入口温度及压力的关系。
1. 传热恶化是在壁面温度达到拟临界温度或流体平均温度达到临界温度时产生的;2. 换热系数随质量流量的增加或壁面热流的降低而增大;3. 通过提高煤油的压力可以显著降低恶化现象。
关键词航空煤油 传热恶化 超临界 数值研究
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