Effect of Aspect Ratio of Solar Chimney Cavity on Performance of Natural Ventilation and Smoke Exhaustion in Tunnel
In order to investigate the performance of solar chimney adopted at tunnel under natural ventilation and fire conditions,the numerical code was employed to simulate the airflow and smoke propagation in tunnel with varied ratio of cavity width to cavity gap. The variation law of volumetric flow rate at cavity inlet was analyzed. The solar radiation intensities varied from 400W/m2 to 1200W/m2. The ratios of cavity width to cavity gap of solar chimney was in range from 1.5 to 6 with same area of 24m2. The fire powers of 3MW,10MW,20MW were conducted. Results show that the absorbed heat power in per unit area increased with the solar radiation that induces the higher airflow velocity,and the airflow velocity linearly improves with q1/3. The volumetric flow rate at inlet linearly increases with 2/3 power of cavity gap and cavity width. The larger ratio of cavity width to cavity gap enhances the volumetric flow rate but weaken the smoke exhaustion. The smoke exhaustion rate increases with Q1/3 and hc1/2. The optimum chimney configuration with 12m width and 2m gap can exhaust all smoke from upstream. A modified model is developed for predicting the airflow rate and smoke exhaustion rate through solar chimney that the predictions fits in good agreement with numerical modelling. This study contributes to application of solar chimney in tunnel and guides extraction design.
Solar chimneyTunnel fireRenewable energySmoke exhaust shaftAirflow rate
万方数据
维普
