Numerical Simulation Of Convection And Heat Transfer In Large Span Coal Shed Structure

At present,thermal power generation is still the main form of power generation in China,and coal as its main fuel,often needs to be placed in the coal shed for supply in advance.Therefore,large-span coal shed has been widely constructed and applied.Due to the requirement of energy conservation,environmental protection and the strict restriction of building land,the piling of coal must be closed storage.The air quality in the confined space is decreased due to the emission of machines in the coal shed and the oxidization and heat release of coal itself,which may threaten the safety and health of workers.The inner environment of the coal shed is mainly affected by heat and dust.The chemical reaction between the coal heap and the air generates heat,and the coal will produce dust in the transportation,screening and other industrial operations,which has a great impact on the air quality in the coal shed.Firstly,the paper investigates and studies the working environment and physical parameters in the coal shed,and obtains relevant data to ensure that the simulation conforms to the reality.Secondly,CFD numerical simulation was used to establish an accurate mathematical model for the structure,set relevant boundary conditions and parameters,and use Fluent software to solve the problem,thus completing the numerical simulation of natural convection and mixed convection processes in the coal shed.Finally,the paper studies the air distribution form in the large-span coal shed,summarizes the convection heat transfer law,and provides the basis and reference for the optimization design of the industrial coal shed’s convection ventilation and the personal safety of workers.In the process of natural convection simulation,the large-span coal shed is in a closed state.By changing the shape,height,temperature and quantity of the internal heat source,the flow state of the air flow in the structure is studied.However,it can be roughly summarized into three layers: in the first layer,within the range below theheight of the heat source of the structure,the buoyancy plume generated by the heat source is disorderly and upward,and the temperature at the bottom of the structure is relatively low.The second layer has obvious stratification and large temperature gradient from the same height of heat source to the upper middle height.The third layer is a transition zone in a small range at the top of the structure with a small temperature gradient.The temperature in the middle of the two heat sources is slightly higher than the temperature on both sides,and the personnel working in this position need to change shifts after a short period of workCoal shed in summer or transition season in the form of natural ventilation,can save building energy of mixed convection of simulation,by changing the opening of the doors and Windows as well as internal and external to the speed of the wind research structure of convective heat transfer,it is concluded that temperature within a Windows and doors open when the structure has obvious drop,different external wind speed for temperature inside the structure used by the decline in the same time,into the structure of the airflow motion path is almost similar.