Internal Flow Field Of Reefer Containers With Hot Cargo Distribution And Optimization Study

As one of the main means of refrigerated transportation,refrigerated container plays an important role in hot cargo transportation.In recent years,with the increasing demand for fresh agricultural products and the emergence of new demand,the transportation demand has also increased significantly,which catalyses the vigorous development of the cold chain logistics industry as a whole.In the process of using refrigerated containers to transport hot loaded goods,due to the improper stacking method,the flow field in the container is uneven,the temperature difference is large,the goods are rotten or frostbitten,resulting in different degrees of damage,and the utilization rate of container capacity and the waste of cooling capacity.The damage of goods will make the owners suffer huge economic losses.Improper stacking method will also increase the cost of refrigeration and transportation.These are the problems that the owners need to solve urgently.Under this background,this paper studies the distribution and optimization of the internal flow field of refrigerated containers,analyzes the influence of different stacking methods on the internal flow field of refrigerated containers when transporting hot goods,and optimizes the matching relationship between different types of hot goods and different stacking methods based on the characteristics of the flow field,so as to reduce the cargo damage and transportation costs,and reduce the economic losses of owners.This paper uses ansys18.0 as the simulation tool.ICEM CFD is used to establish the mathematical and physical model of refrigerated container,and grid.Each stacking model is imported into FLUENT software for simulation iterative calculation.After the iteration,it is imported into CFD post software for postprocessing of the results.The temperature and velocity distribution nephogram on the special section and the temperature and velocity change curve on the special streamline are obtained to judge the cargo damage at the high temperature accumulation.Three sections,YZ,XZ and XY,and the temperature and velocity curves on the two streamlines are selected to verify the influence of different stacking methods on the flow field distribution inside the refrigerated container.The internal space utilization rate of integral stacking refrigerated container is the highest,but the cold air channel of this stacking mode is single,which is not conducive to the air circulation in the box to transport the heat out of the box,and it is easy to produce local high temperature,resulting in more damage to the hot goods.The temperature difference in the box is smaller than that of the whole stacking.Compared with the whole stacking and the horizontal and layered two-body stacking,the direction of the cold air channel is reasonable,which increases the contact area between the goods and the cold air,helps the cold air circulation,and increases the uniformity of the flow field distribution.With the increase of four body stacking cold air channels,the reserved two cold air channels can take away the heat in the refrigerated container in time,increase the circulation efficiency of cold air in the container,so that the cold energy can be more evenly and effectively transported to all parts of the refrigerated container,better avoid the local high temperature caused by the airflow vortex,and effectively reduce the cargo damage rate.The overall temperature difference in the box is small,the distribution of temperature and speed is uniform,there is no obvious high temperature area in the whole box,the cold air circulation is good,and the refrigeration effect is the best,which meets the transportation requirements of most hot goods.After simulation,the temperature difference in the box is 7.2 ℃ for integral stacking,5.4 ℃ for horizontal two-body stacking,3.3 ℃ for longitudinal two-body stacking,4.2 ℃ for layered two-body stacking and 2.3 ℃ for four body stacking.According to the simulation results,the location of local high temperature inside the refrigerated container is judged,the main damage points are found,and the advantages and disadvantages of various stacking methods are analyzed.Combined with the comprehensive consideration of the types of hot goods,loading and unloading conditions,and the length of transportation distance,the suitable stacking transportation forms of some hot goods are listed.On the premise of using the characteristics of flow field,the matching relationship between different types of hot cargo and stacking transportation mode is optimized,and the reasonable suggestions of stacking transportation are put forward.