内置双螺旋结构换热管金属氢化物反应器的传热性能

针对金属氢化物反应器传热性能较差的问题，提出了更紧凑高效的双螺旋结构换热管。建立了内置螺旋管的金属氢化物反应器的三维数学模型，研究了换热流体入口平均流速对反应器传热性能的影响，确定了模拟中入口平均流速的范围，对比分析了单、双螺旋结构对反应器性能的影响。结果表明：在换热流体入口平均流速大于0.5m/s以后，能达到较好的换热效果，换热流体的平均真实温升趋于稳定。减小螺旋导程可以明显提高换热流体的平均真实温升和反应器的传热性能。对于导程为60mm的单、双螺旋结构管，床层平均温度降至300K所用时间从7000s缩短到3000s。导程为30mm的双螺旋结构管的单位重量输出?功率比导程为15mm的单螺旋结构管更高，可见内置双螺旋结构管反应器的传热性能优于内置单螺旋结构管反应器。双螺旋结构管具有更大的换热面积，在反应器床层内的位置分布更加均匀，从而提高了反应器的传热性能。

Heat Transfer Performance of Metal Hydride Reactor Incorporating a Heat Exchange Tube with Double Helix Structure

Given unsatisfactory heat transfer performance of the metal hydride reactors, a more compact and efficient heat exchanger tube with double helix structure was proposed. A three-dimensional model was established for the metal hydride reactors incorporating helically coiled tubes. The influences of the inlet mean velocity of the heat transfer fluid on the heat transfer performance of the reactors were investigated, and the range of the inlet mean velocity in the simulation was determined. Furthermore, the effects of the single and double helix structures were analyzed. The results show that when the inlet mean velocity of the heat transfer fluid is greater than 0.5 m/s, the heat transfer performance reaches a desirable level, and the average true temperature boost of the heat transfer fluid tends to stabilize. Furthermore, the average true temperature boost of the heat transfer fluid and the heat transfer performance of the reactors are significantly improved by reducing the helical pitch. For the single and double helix tubes with a 60 mm helical pitch, the time for reducing the average bed temperature to 300 K is shortened from 7000 s to 3000 s. Besides, the double helix tube with a 30 mm helical pitch has the higher gravimetric exergy-output rate than the single helix tube with a 15 mm helical pitch. These results suggest that the reactor with double helix tube has better heat transfer performance than the one with single helix tube. The double helix tube has a larger heat transfer area, and is more uniformly distributed in the metal hydride beds, thereby improving the heat transfer performance of the reactors.