套管对空温式气化器传热的影响

在空温式气化器翅片管内加装套管，将翅片管与套管作为整体建立传热计算模型，采用计算流体力学(CFD)数值模拟空温式气化器的传热过程，获得不同内径( φ6、φ8、φ10 mm)套管气化器流速、温度、气含率、传热系数的分布规律。搭建套管结构空温式气化器实验平台，通过实验验证数值模拟结果的可靠性。结果表明：模拟的气化器出口温度和实验结果误差为4.75%~6.46%，翅片表面的温度误差在7%以内，验证了数值模拟所采用假设的准确性；套管对传热管内流体的流动特性具有扰动作用，并提高了其换热能力；3种规格套管中  φ6 mm套管翅片表面温度最高，其气含率比无套管结构提高4%，强化传热效果最优。

Effect of Double-wall Heat Transfer Tube on Heat Transfer of Ambient Air Vaporizer

 A heat transfer calculation model was established by adding a double-wall heat transfer tube inside the finned tube of air temperature vaporizer. The heat transfer process of ambient air vaporizer was simulated by computational fluid dynamics (CFD), thus obtaining the distribution of gas velocity, temperature, gas holdup and heat transfer coefficient of the vaporizers incorporating double-wall heat transfer tubes with different inner diameters (  φ6, φ8, φ10 mm). An experimental platform for ambient air vaporizer with double-wall heat transfer tube was built to verify the reliability of numerical simulation results through experiments. The results show that the error between the simulated and experimental results of the outlet temperature of ambient vaporizer is 4.75%—6.46%, and the error in fin surface temperature is within 7%, which verifies the accuracy of the assumptions used in numerical simulation. The double-wall heat transfer tube has a disturbing effect on the fluid flow in the plate-fin heat transfer tube, and accordingly improve the heat exchange capability. Among the three specifications of double-wall heat transfer tube, the φ6 mm tube has the highest surface temperature and the best heat transfer enhancement effect, and its gas holdup is 4% higher than that of the ordinary heat transfer tube.