Airflow Analysis Of Marine Air-Conditioning Unit Cabinet

The air-conditioning unit cabinet adopts advanced air-conditioning technology to comprehensively adjust the storage environment of fruits and vegetables by reducing temperature,controlling humidity and adjusting oxygen concentration.This will help to achieve longer preservation time,freshness maintenance of fruits and vegetables,and reduction of dry loss.At the same time,featuring small volume,easy installation and reduced interaction between fruits and vegetables,the air-conditioning unit cabinet is preferred on ocean-going vessels.It is practically important for enriching the crew's diet,ensuring balanced nutrition and the health of the personnel.Therefore,by the application of computational fluid dynamics software,this paper,taking the marine air-conditioning unit cabinet as the research object,focuses on the study of the airflow organization of the unit cabinet refrigeration process and the personnel entering and leaving process.Based on the calculation results,it provides a reference for the engineering practice.The main work is as follows:A unit cabinet model is built via Airpak software.numerical simulation Numerical simulation was carried out according to the experimental conditions,and the correctness of the turbulence model was verified by comparing the experimental data with the simulation results;The unit cabinet model is established,including setting different fan installation schemes,air-supplying speed and fruit and vegetable basket gap,to study the temperature field,velocity field and relative humidity field distribution of the internal airflow organization of the unit cabinet under different working conditions.Through the analysis of the calculation results,the most suitable conditions for the preservation of fruits and vegetables are selected.Because the low oxygen concentration of the air-conditioning unit cabinet during the refrigeration process,it is necessary to charge the low-temperature air to ensure the absolute safety of the personnel.By studying the correspondence between different wind speeds and the time required for the oxygen concentration in the unit cabinet to reach the safety value,it provides certain references for safety management;When the unit cabinet is not occupied,it needs to be filled with nitrogen to reduce the oxygen concentration.The correspondence between the wind speed and the time required for the oxygen concentration in the unit cabinet to reach the target value provides a reference for the engineering practice.During the refrigeration process,it is better to air the cabinet through the long side of two air coolers from the same direction,rather than the opposite air supply or the reverse air supply mode.When the power of the air cooler is stationary,the air supply temperature will increase if the wind speed up,which will result in lower humidity inside the cabinet.When the gap between the fruit and vegetable baskets increases,the temperature in the fruit and vegetable areas will decrease,and the temperature and relative humidity in the cabinet will be more evenly distributed.During the process of personnel entering and leaving,when the wind speed exceeds 2m/s,the influence of the air supply speed on time is gradually reduced;when the air supply speed exceeds 4m/s,the time difference of reaching the target concentration at different wind speeds is small.In engineering practice,the wind speed can be adjusted within the range of 2m/s-7m/s according to actual needs.