Optimal Design And Load Mitigation Analysis Of A Novel Dry Coal Shed Balancing Ventilation And Dust Suppression Effects

In order to prevent coal dust pollution,dry coal sheds are commonly used in power plant coal yards.Closed gable walls are adopted in traditional dry coal sheds,which is beneficial in enhancing the dust suppression rate,but the natural ventilation rate is greatly reduced;when the gable walls are completely open,the natural ventilation rate is improved,but the dust suppression effect is very limited under specific wind direction.However,the natural ventilation effect is improved,the dust disturbance caused by ventilated flow in the dry coal shed is enhanced.Therefore,the ventilation rate and dust suppression rate of the dry coal shed are factors that acts oppositely.Moreover,it is important to ensure a certain ventilation capacity as well as a good dust suppression performance.In order to balance the ventilation and dust suppression effects,this study proposes a new type of coal shed with porous gable walls.The porous gable walls can balance the ventilation and dust suppression effects,as well as mitigate the wind load at an optimal permeability rate.However,the existing studies are not addressed on how the dust suppression effect is affected by the gable permeability.And,the research on the effect of ventilation in dry coal shed with porous gable walls are also lacking.Moreover,the dry coal shed is a large-span structure with strong sensitivity to wind load,the effect of porous walls on the wind load of the new dry coal shed is rarely studied.Therefore,this study investigates the ventilation rate and dust suppression rate of the new dry coal shed with different permeability of porous walls by using wind tunnel test and CFD numerical simulation,the optimal permeability rate of porous walls is determined by analyzing the comprehensive performance of ventilation and dust suppression under different permeability rates,so as to provide the theoretical basis for the optimal design of the new dry coal shed.Finally,the effect of wind load on the dry coal shed with different permeability of gable walls was studied by wind tunnel test.The main research contents and results are as follows:(1)The dry coal shed with porous gable walls has superior ventilation performance.The ventilation characteristics joint action of wind and heat pressure is similar to the wind pressure ventilation,and the ventilation effect of dry coal shed is more closely related to the form of gable walls and the permeability of porous gable walls,and the top ventilator can effectively increase the heat pressure ventilation effect of dry coal shed.Under the optimal permeability of the gable walls,the natural ventilation rate can be increased from 0.7 times/hour to more than 3.0 times/hour compared with the closed gable walls.(2)Closed storage of dry coal sheds can effectively reduce the amount of dust emission.A fully enclosure exhibits the best dust suppression performance.A new dry coal shed ventilation and dust suppression optimization design guideline with the objective of maximizing the ventilation and dust suppression factor is proposed,and the optimal gable walls permeability rate is determined as 30%.Under the optimal permeability of the gable walls,the dust suppression rate of the dry coal shed can be increased from 56% to 80%,and combined with regular spraying can further effectively control dust,making the dust suppression rate reach more than 90%.(3)Porous permeable panels can significantly enhance the flow of airflow and reduce the suction force caused by separated flow.and the average and extreme lift coefficients on the roof edge,top ventilator and gable walls are significantly reduced,but the regional values of average and peak wind pressure coefficients are not sensitive to the porosity of porous gable walls.The use of porous gable walls instead of closed/open gable walls reduced the peak suction on the gable walls by more than 70%and the peak suction in the central area of the roof and top skylight by about 20%.The new dry coal shed with porous gable walls can effectively reduce the wind load Thus,providing a economic construction plan.