低压省煤器H型鳍片管优化传热数值研究

为研究低压省煤器H型鳍片管的传热特性及阻力特性,采用realizable湍流模型数值研究H型鳍片管管束外烟气的流动传热特性。研究结果表明:H型鳍片管具有均匀气流的作用,在管壁面形成的漩涡能够加强通道内绕流作用,利于强化传热;当烟气的流速越高,H型鳍片管传热系数越大,流动阻力逐渐增大;当鳍片节距增加,H型鳍片管传热系数增加,流动阻力逐渐降低;在节距为18 mm时,鳍片管传热系数较高,流动阻力最小,选用18 mm的鳍片节距最为经济。

Numerical simulation on heat transfer optimization of H-type finned tube in the low pressure economizer

In order to investigate heat transfer and resistance characteristics of H-type finned tube in the low pressure economizer, realizable turbulence model was adopted to analyze flow and heat transfer characteristics of flue gas covered by H-type finned tube. The results show that the H-type finned tube can make the airflow become uniform; the vortexes formed on the wall are favorable to enhance heat transfer because of detouring flow in the channel; the higher velocity of flue gas is, the larger heat transfer coefficient of H-type finned tube and flow resistance will be; with the increase of pitch of the finned tube, the heat transfer coefficient increases, flow resistance decreases; when the pitch of H-type finned tube is 18 mm, the value of heat transfer coefficient reaches a peak and flow resistance is smallest. Therefore, the selection of 18 mm-pitches H-type finned is most economical.