水在螺旋盘管内的换热及压降特性研究

西安科技大学 能源学院,陕西 西安 710054

螺旋盘管; 换热系数; 压降

Heat transfer and pressure drop characteristics for water flowing in spiral coil
ZHANG Xiao-yan,ZHAO Shan-yuan,HONG Shan-hu

(College of Energy Science and Engineering,Xi'an University of Science and Technology,Xi'an 710054,China)

spiral coil; heat transfer coefficient; pressure drop

备注

螺旋盘管及螺旋套管换热器因其优越的结构特性和高效的换热效率,在制冷、空调、热泵、化工等领域内都得到了广泛应用,研究水在这类换热器中的对流换热与压降具有重要的实用价值。文中对水在4种不同结构参数的螺旋盘管换热器内的换热及压降特性进行实验研究,工况范围:Re为4 000~9 000,水的体积流量为200~350 L/h,加热功率为80~350 W.实验结果表明:水的平均换热系数与压降均随Re的增加而增大,相同Re时,最大平均换热系数出现在SC型螺旋盘管中,这是因其最小的弯曲半径所致; 水在BE型螺旋盘管内的压降最大,SC型次之,这是因管长与弯曲半径共同影响所致。平均换热系数随加热功率的增加而增大,相同加热功率时,水在SC型螺旋盘管中的换热系数最大,BE型始终大于SE型,而BC型随水流量的不同而异。实验结果与计算结果的比较表明:螺旋盘管的换热强化作用随Re增大而逐渐减弱,在4种螺旋盘管中,SC型具有最佳的换热强化效果,这一结果与实验结果相吻合。研究结论为螺旋盘管及螺旋套管换热器在诸多领域内的应用提供了参考依据。

Because of their superior structure property and high heat exchange efficiency,the spiral coil and spiral tube in tube heat exchangers are widely used in refrigeration,air conditioning,heat pump,chemical and other fields,it has important practical value for the study of heat transfer and pressure drop characteristics for water flowing in such heat exchangers.The heat transfer and pressure drop characteristics for water flowing in four spiral coil heat exchangers with different shapes and different sizes were experimental studied.Reynolds number range from 4 000 to 9 000,volume flow rate range from 200 to 350 L/h and heating power range from 80~350 W.The experimental results indicate: the average heat transfer coefficient and pressure drop increase with increasing Re,and the greatest average heat transfer coefficient appears in SC spiral coil,which bending radius is smallest; the greatest pressure drop appears in BE spiral coil,the second is in SC spiral coil,because of the combined influence of tube length and bending radius.The heat transfer coefficients increase with increasing heating power,the greatest average heat transfer coefficient also appears in SC spiral coil,the heat transfer coefficient in BE is always greater than in SE,and the comparison results of heat transfer coefficient in BC is changing with flow rate.The comparison of calculations with experimental results indicate: heat transfer enhancement effect of spiral coils weaken with the increasing Re,the greatest heat transfer enhancement effect appears in SC spiral coil,this is according with experimental results.The conclusion of this paper provides reference for the application of spiral coil and spiral tube in tube heat exchangers in many areas.