| With the rapid development of the cold chain logistics market,automated stereoscopic cold storage has come into being.At present,the cold storage operated in the market generally has the problem of low utilization of land area and energy.In contrast,the emerging automated stereoscopic cold storage has a high utilization rate per unit area,can effectively control the phenomenon of running cold,the temperature fluctuations in the storage range is small,and other characteristics,so it has efficient operation and the practicality of creating a stable low-temperature storage environment.Domestic airflow organization of small cold storage research is more adequate,but the stereoscopic cold storage chiller cooling airflow distribution characteristics of the current study is still relatively small.At present,there is arbitrariness in the selection of airflow organization design scheme of the completed stereoscopic cold storage,so it is important to carry out research on airflow organization of stereoscopic cold storage.In this paper,the airflow organization of an automated stereoscopic cold storage is studied by using Computational Fluid Dynamics(CFD)technology,and the effects of different air velocities,air supply temperatures,installation locations of chillers and different stacking forms,palletizing heights and layering spacing of goods on the flow field are analyzed.The main research contents are as follows:The heat load calculation and simulation model based on the building structure of the stereoscopic cold storage were carried out and verified using literature experimental data and empirical formulas,and the accuracy met the requirements.The study was carried out on the unloaded cold storage with different air supply velocities of chillers,different air supply temperatures and different installation positions,and the cold storage capacity and the ability to maintain temperature stability of the stereoscopic cold storage were analyzed.The results showed that the air supply speed was 12.7 m/s,and the airflow organization in the warehouse was distributed regularly,which could ensure the cooling rate and temperature field uniformity.The cooling time is positively correlated with the air supply temperature,and the effect of changing the air supply temperature on the airflow organization is not significant;the chiller adopts the mainstream backward type,which can reduce the mutual interference of the airflow,and the velocity field of the airflow organization in the warehouse is zigzag distribution,and the temperature distribution of the central cargo field is uniform,which can improve the freezing effect of the cold storage and realize rapid and balanced pre-cooling.A porous media model is used for the goods,and the airflow organization in the warehouse is simulated from the different placement forms,palletizing heights and layering spacing of the goods.The results show that the shelves are placed horizontally in the form of air flow from the chiller,the flow field is evenly distributed,and the cooling performance is improved by nearly 8%;the shelves are placed in the form of one-line without division to improve the space utilization without affecting the cooling performance;when the height of cargo palletizing is 13 layers,the space volume utilization is 0.45,and the temperature field uniformity is improved by 13.04% year-on-year.Under the condition of loading goods in the cold storage,when the air supply speed is 12.7 m/s,the pre-cooling time is reduced by90.42%,the temperature unevenness is 0.011,the uniformity is nearly doubled,and the cooling speed of goods surface is basically the same.The results of this paper provide a reference for the design scheme of airflow organization in stereoscopic cold storage,which is conducive to improving the cooling performance of cold storage and the cold storage quality of goods,and lays the foundation and makes a useful attempt to study the energy-saving and cost-reducing measures of cold storage. |
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