折边螺旋折流板电加热器换热强化  

Heat Transfer Enhancement of Folded Helical Baffle Electric Heaters

作　　者：王明超[1] 陈亚平[1] 吴嘉峰[1] 

机构地区：[1]东南大学能源与环境学院,能源热转换及其过程测控教育部重点实验室,南京210096

出　　处：《工程热物理学报》2016年第10期2206-2210,共5页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.51276035)

摘　　要：对倾斜角为20°、25°、30°单头及30°双头"斜日字"单元环形布管方式的周向重叠三分折边螺旋折流板电加热器方案进行了热力性能模拟,并与相同布管方式板间距为200、250 mm的弓形折流板电加热器方案进行了数值模拟结果对比。结果表明,倾斜角为25°的折边螺旋折流板方案的换热系数较高,综合指标最高,同时加热管表面平均温度较低。而弓形折流板方案中板间距越大,其换热系数和压降越低,平均温度越高。与板间距200 mm的弓形折流板方案S200相比,三分折边螺旋折流板方案H25°的传热系数与综合性能指标h.△p^(-1/3)分别提高了18.3%和29.8%,同时压降及加热管表面平均温度分别下降了24.3%和45.6 K。Flow and heat transfer property simulation was performed on both helical and segmental baffle electric heaters of equilateral tube layout with one-plus-two U-tube units,including four helical baffle electric heaters which have folded circumferential overlapped baffles with inclined angles of20°,25° and 30° single thread and 30° dual threads respectively and two segmental ones which have baffle plate spans of 200 and 250 mm respectively.Simulation results show that the scheme with inclined angle of 25° has the highest comprehensive index and high heat transfer coefficient with low tube surface temperature;while the segmental baffle scheme with greater span has lower heat transfer coefficient and pressure drop but higher tube surface temperature.Compared with those of segmental scheme with baffle span of 200 mm,the heat transfer coefficient and the comprehensive index h·△p^-1/3 of helical electric heater with inclined angle of 25° increase by 18.3%and 29.8%respectively,while the pressure drop and the average temperature on tube surface reduced by 24.3%and 45.6 K respectively.

关 键 词：电加热器 三分螺旋折流板 端部折平 综合指标 表面温度 

分 类 号：TK172[动力工程及工程热物理—热能工程]