A Calculation Method of Convective Heat Transfer Coefficient in Ventilation Tunnels

The ventilation tunnel is an essential structure for ventilation and heat dissipation in underground buildings. Research on the calculation method of convective heat transfer coefficient in ventilation tunnels is of great significance for energy conservation in underground buildings. By comparing the theoretical equation for calculating convective heat transfer coefficient in pipes and the correlation equation for convective heat transfer coefficient in underground air ducts, a new correlation equation for calculating convective heat transfer coefficient in ventilation tunnels considering the thermal entrance effect is proposed. Through the analysis of measured data from a ventilation tunnel of hydropower Station in Guiyang and experimental data from a ventilation tunnel of a hydroelectric power station in Jiangxi mentioned, it is demonstrated that the proposed correlation equation is more accurate than the previous one. Simultaneously, the energy saving potential of multi-entrance ventilation tunnels is proved by the analysis of measured data, and the effect of heat transfer gain on the main ventilation tunnel caused by the secondary ventilation tunnel is proved by the proposed correlation equation.