Heat transfer and critical heat flux of subcooled water flow boiling in a HORIZONTAL circular tube
Heat transfer and critical heat flux of subcooled water flow boiling in a HORIZONTAL circular tube
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DOI：
10.1016/j.expthermflusci.2012.10.001
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发表时间：
2013
影响因子：
3.2
通讯作者：
K. Hata;Y. Shirai;S. Masuzaki
中科院分区：
文献类型：
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作者：
K. Hata;Y. Shirai;S. Masuzaki
本文采用实验水环流系统地测量了流速u分别为4.15、7.05、10.07和13.50m/s时，不同指数周期（Q= Q 0 exp（t/τ），τ=6.55-21.81s）的指数增长热输入引起的稳态湍流换热。对内径为6 mm、有效长度为59.2mm、厚度为0.4mm的水平铂（Pt）圆形试管进行测量。阐明了稳态湍流传热与流速的关系。本文系统地测量了水平SUS 304圆管内过冷水流动沸腾的稳态核态沸腾传热和稳态临界热流密度（u=3.93-13.86m/s），进出口过冷度（ΔTsub，out=60.40-130.30K和ΔTsub，in=81.30-154.20K）、入口压力（Pin=786.29-960.93kPa）和增加的热输入（Q 0 exp（t/τ），τ=8.36s）。本工作采用内径d= 6 mm、加热长度L=59.4mm、有效长度Leff=48.4mm、L/d =9.9、Leff/d =8.06、壁厚δ=0.5mm、表面粗糙度Ra=3.89μm的卧式SUS 304试管。在流速u为3.93-13.86m/s范围内，对水平SUS 304圆管过冷水流动沸腾的非平衡态传热和稳态传热特性进行了研究。本文将稳态THT、NBHT和稳态CHF数据与作者根据流速u为4.0 ~ 42.4m/s的垂直圆形试验管的实验数据，用THT关联式、NBHT关联式和瞬态CHF关联式计算出的关于进出口过冷度的数据进行了比较。本文详细研究了水平圆管中的THT、NBHT和过冷流动沸腾CHF随实验方位的变化规律，并根据实验数据导出了THT、NBHT和瞬态CHF随进出口过冷度变化的可预测关联式。水平管的THT关联式、NBHT关联式和瞬态CHF关联式在ΔTsub，out、ΔTsub，in和u的宽范围内均能描述THT数据、NBHT数据和过冷流动沸腾CHF数据，误差在±15%以内。
The steady-state turbulent heat transfer (THT) due to exponentially increasing heat inputs with various exponential periods (Q=Q0exp(t/τ), τ=6.55–21.81s) were systematically measured with the flow velocities, u, of 4.15, 7.05, 10.07 and 13.50m/s by an experimental water loop flow. Measurements were made on a 6mm inner diameter, a 59.2mm effective length and a 0.4mm thickness of HORIZONTAL Platinum (Pt) circular test tube. The relation between the steady-state turbulent heat transfer and the flow velocity was clarified. The steady state nucleate boiling heat transfer (NBHT) and the steady state critical heat fluxes (CHFs) of the subcooled water flow boiling for HORIZONTAL SUS304 circular test tube were systematically measured with the flow velocities (u=3.93–13.86m/s), the outlet and inlet subcoolings (ΔTsub,out=60.40–130.30K and ΔTsub,in=81.30–154.20K), the inlet pressures (Pin=786.29–960.93kPa) and the increasing heat input (Q0exp(t/τ), τ=8.36s). The HORIZONTAL SUS304 test tube of inner diameter (d=6mm), heated length (L=59.4mm), effective length (Leff=48.4mm), L/d (=9.9), Leff/d (=8.06) and wall thickness (δ=0.5mm) with surface roughness (Ra=3.89μm) was used in this work. The NBHT and the steady state CHFs of the subcooled water flow boiling for the HORIZONTAL SUS304 circular test tube were clarified at the flow velocities, u, ranging from 3.93–13.86m/s. The steady-state THT data, the NBHT ones and the steady state CHF ones were compared with the values calculated by authors’ THT correlation, their NBHT ones and their transient CHF ones against outlet and inlet subcoolings based on the experimental data for the VERTICAL circular test tubes with the flow velocities, u, ranging from 4.0 to 42.4m/s. The influences of test tube orientation on the THT, the NBHT and the subcooled flow boiling CHF are investigated into details and the widely and precisely predictable correlations of the THT, the NBHT and the transient CHFs against outlet and inlet subcoolings in a HORIZONTAL circular test tube are derived based on the experimental data. The THT correlation, the NBHT ones and the transient CHF ones for the HORIZONTAL test tube can describe the THT data, the NBHT ones and the subcooled flow boiling CHF ones for the wide ranges of ΔTsub,out, ΔTsub,inand u obtained in this work within ±15% difference.