干湿工况平直翅片传热传质特性数值模拟

Numerical Investigation of Heat and Mass Transfer Characteristics of Plain Fin Under Both Dry and Wet Condition

本文建立了湿工况条件下湿空气析湿换热的数值模型,对平直翅片在干湿工况的传热传质特性进行了数值模拟研究。研究结果表明,湿工况时传热系数增大,但翅片效率降低,对流换热量减小;干工况时,增大纵向管间距会导致传热系数降低,但湿工况时,纵向管间距对传热传质因子的影响可以忽略;传热因子随横向管间距增大而增大,随翅片间距和管排数的增大而减小;拟合得到了传热传质因子的多参数拟合公式。

Numerical model for heat transfer of wet air under dehumidifying condition is proposed in this paper. Numerical study for the characteristics of heat and mass transfer of plain fin under both dry and wet condition is carried out based on the model. Under wet condition, the plain fin has lager heat transfer coefficient and smaller fin efficiency when compared with dry condition. The convective heat flux is reduced when dehumidifying process occurs on fin surface. Larger longitudinal tube pitch leads to smaller heat transfer coefficient under dry condition. Under wet condition, the effect of longitudinal tube pitch on heat transfer coefficient is not significant. The heat transfer coefficient also increases with the increase of spanwise tube pitch and decreases with the increase of fin pitch. Based on the numerical simulation, correlations for both heat and mass transfer factors are proposed.