直流锅炉垂直管圈水冷壁低流速自补偿特性的试验研究  

Experimental Study of the Low Flow Speed Self-compensation Characteristics of the Vertical Coil-tube Water Wall of an Once-through Boiler

作　　者：朱晓静[1] 毕勤成[1] 杨冬[1] 王建国[1] 

机构地区：[1]西安交通大学能源与动力工程学院,陕西西安710049

出　　处：《热能动力工程》2010年第4期418-422,共5页Journal of Engineering for Thermal Energy and Power

摘　　要：针对试验条件下结构为Φ28.6×5.8mm的四头优化内螺纹管,进行了垂直并联双管低质量流速下自补偿特性的试验研究,结果表明:垂直并联管组在试验参数范围内具有明显的自补偿特性;在管内工质的汽化过程中热负荷较小的支管内工质的质量流速随着吸热量的增加先减小再增大,当管内工质的干度随吸热量增加而达到较高时,管内工质的质量流速逐渐接近或超过平均质量流速,系统的自补偿特性渐渐消失。结果还表明:工质干度较低时,较大的热负荷偏差会强化系统的自补偿特性,而工质干度较高时,较大的热负荷偏差会减弱系统的自补偿特性;另一方面,工质干度较低时,系统压力的增大会减弱垂直管屏的自补偿能力;当工质干度较高时,系统压力的增大会导致两相摩擦压降减小,导致系统的自补偿特性增强。With φ28.6×5.8 4-head optimized inner threaded tubes serving as a structure under test conditions,experimentally studied were the self-compensation characteristics of two vertical parallel tubes at a low mass flow speed.The test results show that such a vertical parallel tube group enjoys conspicuous self-compensation characteristics within the test parameter range.During the vaporization of the working medium in the tubes,the mass flow speed in the branch tubes with a relatively small heat load will first decrease and then increase with an increase of the heat absorbed.When the dryness of the working medium in the tubes reaches a relatively high one with an increase of the heat absorbed,the mass flow speed of the medium in the tubes will gradually approach or exceed the average mass flow speed and the self-compensation characteristics of the system will gradually disappear.The test results also indicate that when the medium dryness is relatively low,a relatively big heat load deviation can strengthen the self-compensation characteristics of the system.When the medium dryness is relatively high,a relatively big heat load deviation can weaken the self-compensation characteristics of the system.On the other hand,when the medium dryness is relatively low,an increase of the system pressure may weaken the self-compensation capability of the vertical tube platen.When the medium dryness is relatively high,an increase of the system pressure may result in a decrease of the two-phase friction pressure drop,leading to an enhancement of the self-compensation characteristics of the system.

关 键 词：直流锅炉 自补偿特性 优化内螺纹管 低质量流速 

分 类 号：TK224.2[动力工程及工程热物理—动力机械及工程]