Thermal test and numerical simulation of cooling stave with internal ribbed tube

A new type of cooling stave with internal ribbed tube was proposed,and the heat transfer performance of the stave was studied by means of thermal test and numerical simulation.The temperature of cooling stave was monitored in the conditions of furnace gas temperature of 200-700 C and cooling water velocity of 0.2-1.0 m/s.The thermal test results show that the internal rib structure can form swirl in the water pipe and improve the cooling capacity of the cooling stave.The higher the furnace temperature or the lower the cooling water flow rate,the more obvious the advantage of the cooling stave with internal ribbed tube.The mathematical model of the cooling stave with internal ribbed tube was established by FLUENT software,and the influence of the internal rib structure parameters on the heat transfer performance of the cooling stave was discussed.It is suggested that the parameters of the internal ribbed tube should be 4 ribs,1 mm in height,5-7 mm in width,and 20-30 mm in lead.In the same common working conditions of the cooling stave,the maximum temperature of the newly designed cooling stave with internal ribbed tube is reduced by 5.6%compared with that of common cooling stave with round tube.The water flow rate in the internal ribbed tube only needs 0.9 m/s to reach the cooling effect of 2 m/s in the common tube cooling stave,which can save 55%of water.In case of water shortage accident of cooling stave,the maximum temperature of the cooling stave with internal ribbed tube is decreased by 22.4%compared with that of common round tube,which can effectively reduce the harm of water shortage and protect the cooling stave.

全封闭扇冷式电机风路优化设计

文章介绍了一种采用复合风路的全封闭扇冷式(TEFC)电机。通过在普通TEFC电机筋冷式机座上四个圆周均布的通风道内,增设若干圆形冷却管,从而以从外风扇处导入冷却风的形式,提升内循环的热交换容量;通过在筋冷式机座圆周均布的散热筋之间的楔形空间中增设冷却管,提升外风路的热交换面积。复合风路的应用有效提升了TEFC电机的散热能力,大幅提升了TEFC电机的功率密度。

超临界压力下内螺纹管摩擦阻力特性研究

该文研究了国产６００ Ｍ Ｗ 直流锅炉水冷壁内螺纹管在超临界压力下的摩擦阻力特性。试验段为２８ ×５ ．４１ｍ ｍ 的四头１２ Ｃｒ１ Ｍｏ Ｖ 内螺纹管，试验参数为压力 Ｐ＝ ２３ ～２７ Ｍ Ｐａ ，质量流速 Ｇ＝ ６００ ～１８００ｋｇ／ｍ ２·ｓ，工质焓ｈ ＝ ６００ ～２６００ｋ Ｊ／ｋｇ ，雷诺数 Ｒｅ ＝ ５ ×１０４ ～１ ×１０６ 。通过试验，得到了内螺纹管的摩擦阻力系数及其随压力、质量流速、工质焓和雷诺数变化的规律。根据试验数据，总结出了超临界压力下内螺纹管的摩擦阻力系数经验关系式。为锅炉的设计和运行提供了可靠的依据。图８ 表１

亚临界压力区内螺纹管汽水流动摩擦压降特性对比

在9-22 MPa亚临界压力区,基于Fortran程序针对不同螺纹结构的垂直上升内螺纹管汽水单相和两相流动的摩擦压降特性进行数值对比研究.研究表明:螺纹结构对内螺纹管的流动特性有显著影响;与光管相比,内螺纹管有较大的摩擦系数,摩擦系数随着内螺纹管螺纹当量N的增加而增大;内螺纹管的两相摩擦压降倍率φl02在低干度值时受N值影响较小,压强越大,差距越小;φl02随压力增大而减小,随蒸汽干度χ增加2l0φ先增加,随后增幅减小,在χ>0.9时有下降的趋势.研究结果为动力工程中内螺纹管的优化提供理论依据.

螺纹管冷却壁传热分析及结构优化研究

将螺纹管应用于高炉冷却壁,利用Fluent软件建立螺纹管冷却壁数学模型,通过数值模拟对螺纹结构进行了优化。建议螺纹管结构参数:肋条数4,肋高1 mm,肋宽5~7 mm,导程20~30 mm。与普通圆管冷却壁的对比研究表明:在冷却水流速为2 m/s工况下,螺纹管冷却壁热面最高温度下降5.6%,但水管进出口压差增长1.69倍;同等冷却效果下,螺纹管冷却壁可节省冷却水量55%;发生缺水事故时,螺纹管冷却壁热面最高温度下降22.4%,能有效降低缺水危害,保护冷却壁。