An experimental investigation was performed on the convective boiling heat transfer of the annular flow in concentric and eccentric annuli with a central heating rod in an unheated tube. Advanced measurement techniques including laser-induced fluorescence (LIF) and confocal chromatic sensor (CCS) were applied to acquire the dynamics and instabilities of the liquid thin film on the tube. The boundary conditions were as follows: heating rod heat flux from 167 kW/m² to 201 kW/m² and mass flow rate from 58 g/s to 155 g/s. The annuli which the flow occurred has a hydraulic diameter of 15.5 mm. As indicated previously by the research on isothermal annular flow in bare tubes, the vapor superficial velocity is the primary factor that influences the liquid film dynamics including the base film thickness and wave amplitude. The liquid film thickness in the eccentric geometry was observed to be constant for liquid superficial velocities from 0.15 m/s to 0.34 m/s and vapor superficial velocities from 6.5 m/s to 13.2 m/s. The heat transfer coefficient ranged from 2.734 kW/m²∙K to 4.279 kW/m²∙K for the concentric geometry and 2.063 kW/m²∙K to 3.096 kW/m²∙K for the eccentric geometry. An increasing trend of the heat transfer coefficient was observed as the liquid superficial velocity increased, whereas the reverse trend was observed for the vapor superficial velocity. When the measured heat transfer coefficient was exceptionally low (< ~2.0 kW/m²∙K), the boiling condition was assumed to be the dry out. An extended range of boundary conditions reported in this study (from the annular flow to the dry out regime) can provide useful data sets for validating computer codes. In particular, the detailed information on liquid film thickness, wave characteristics, and heat transfer coefficient provided in the present paper can help develop annular flow boiling models in computational fluid dynamics.

通过在未加热管中的中心加热棒，对同心和偏心环形空间中环形流的对流沸腾传热进行了实验研究。先进的测量技术包括激光诱导荧光（LIF）和共焦色度传感器（CCS）被用于获取管上液体薄膜的动力学和不稳定性。边界条件如下：加热棒热通量从167 kW / m ²到201 kW / m ²质量流量从58 g / s到155 g / s。发生流动的环的水力直径为15.5 mm。正如先前对裸管中的等温环形流动的研究所表明的那样，蒸汽表观速度是影响液膜动力学的主要因素，包括基膜厚度和波幅。对于从0.15m / s至0.34m / s的液体表面速度和从6.5m / s至13.2m / s的蒸气表面速度，观察到偏心几何形状中的液膜厚度是恒定的。传热系数从2.734千瓦/米不等² ∙K至4.279千瓦/米² ∙K为同心的几何形状和2.063千瓦/米² ∙K至3.096千瓦/米²∙K用于偏心几何。随着液体表观速度的增加，观察到传热系数的增加趋势，而对于蒸气表观速度则观察到相反的趋势。当测得的传热系数极低（<〜2.0 kW / m ² ∙K）时，沸腾条件被认为是干燥的。在这项研究中报道的边界条件的扩展范围（从环形流到干态）可以为验证计算机代码提供有用的数据集。特别是，本文提供的有关液膜厚度，波特性和传热系数的详细信息可以帮助开发计算流体动力学中的环形流沸腾模型。