换热器内逆向折流板对螺旋管传热性能的影响

Effects of Reverse Baffles on the Heat Transfer Performance of Spiral Tubes in Heat Exchangers

为了提高换热器的综合传热能力,以逆向折流板螺旋管(RBST)换热器为研究对象,通过改变折流板与螺旋管的安装方式,获得了更高综合传热性能的RBST换热器;采用双向流-固耦合的计算方法,研究了不同流速和不同结构方案下流体诱导螺旋管振动对RBST换热器综合传热性能的影响,并探讨了螺旋管振动的有效性。结果表明:当RBST换热器内的折流板与螺旋管采用间隙安装时,螺旋管的振幅随入口速度的增加而增加,但其振动频率始终保持不变;螺旋管振动能够增强RBST换热器的综合传热性能,但是强化传热评价指标最高仅为1.0303,效果并不显著,且振动强化传热效果会随着入口速度的增加而削弱;当RBST换热器内的折流板与螺旋管采用无缝安装时,换热器综合性能评价指标最高为1.018,这既延长了螺旋管的使用寿命,又提升了换热器的综合传热性能。

In order to improve the comprehensive heat transfer capacity of heat exchangers,the reverse baffle spiral tube(RBST)heat exchanger is studied.By altering the installation method of the baffle and the spiral tube,a more efficient RBST heat exchanger with enhanced heat transfer performance is obtained.Using a bidirectional flow-solid coupling calculation method,the effect of fluid-induced spiral tube vibration on the comprehensive heat transfer performance of the RBST heat exchanger at different flow rates and under different structural schemes is investigated,and the effectiveness of the spiral tube vibration is discussed.The research findings reveal that that when the baffle and spiral tube are installed with a gap within the RBST heat exchanger,the amplitude of the spiral tube increases with the inlet velocity while its vibration frequency remains constant.The vibration of the spiral tubes can enhance the comprehensive heat transfer performance of the RBST heat exchanger.However,the maximum value of the enhanced heat transfer evaluation indicator is only 1.0303,indicating a modest impact.Furthermore,the effectiveness of intensified heat transfer weakens as the inlet velocity increases.In contrast,when the baffle and the spiral tube inside the RBST heat exchanger are seamlessly installed,the heat exchanger achieves its highest comprehensive performance evaluation indicator of 1.018.This installation not only extends the service life of the spiral tube but also enhances the overall heat transfer performance of the heat exchanger.