CAJ | 학술논문

温度是果蔬贮藏环境最重要的参数.为了研究果蔬进库过程中影响货物温度稳定性的因素,该文以西安某苹果冷藏库为研究对象,建立冷库环境三维非稳态数值求解模型,模拟了进货过程中新进货物摆放间距、进货温度和进货量对达到贮藏条件货物温度稳定性的影响.模拟结果表明,在实际运行管理中,存在适宜的进货温度和进货量,可使苹果贮藏环境受进货过程影响最小,进货效率最高;增大进货间距可以减小对货物温度场的影响,进货摆放间距并不是越大越好.该文研究的冷库,进货过程中货物应先预冷到3℃再进库,进货摆放间距为0.5 m,进货量不大于10%.
온도시과소저장배경최중요적삼수.위료연구과소진고과정중영향화물온도은정성적인소,해문이서안모평과랭장고위연구대상,건립랭고배경삼유비은태수치구해모형,모의료진화과정중신진화물파방간거、진화온도화진화량대체도저장조건화물온도은정성적영향.모의결과표명,재실제운행관리중,존재괄의적진화온도화진화량,가사평과저장배경수진화과정영향최소,진화효솔최고;증대진화간거가이감소대화물온도장적영향,진화파방간거병불시월대월호.해문연구적랭고,진화과정중화물응선예랭도3℃재진고,진화파방간거위0.5 m,진화량불대우10%.
Temperature is one of the most important environmental parameters for fruit or vegetable cold storage. During loading process of fruits or vegetables into cold storage, the new loading goods will influence the temperature stability of goods already settled in the storage room which have reached the storage requirements. Obtaining temperature variation and distribution characteristics in a cold storage during the loading process can provide theoretical reference for optimal design of the cold storage and improve its practical operation and management. To study the factors on the stability of goods temperature during the loading process of fruits and vegetables into cold storage, a combination of CFD (computational fluid dynamics) calculation and experimental study was carried out to further understand the complicated phenomenon of air flow and heat transfer in cold storage. A 3D (three-dimensional) unsteady numerical calculation model of storage environment was developed for a real cold storage with 50 t volume for apples in Xi'an. A ceiling air cooler was equipped in the cold storage. Thek-ε turbulent model was considered as CFD model. The apple zone was regarded as porous medium zone. The influences of the spacing of goods, loading temperature and loading quantity on the temperature stability of goods were numerically studied under the condition that the door was closed and the ceiling air cooler was running. The simulation results were validated by experimental results. The experimental system consisted of temperature sensor and temperature illustration cabinet. The temperature sensor was set at ceiling air cooler's air outlet and connected to the temperature illustration cabinet at test room. The temperature was measured and analyzed once every 2 h. In this study, the reliability of the simulation data was verified by the data of the temperature variation within 24 h after the new goods entered the cold storage. The numerical results were in good agreement with the measured results. The non-uniformity coefficient of temperature was introduced to evaluate the temperature stability of the cold storage. Simulation results showed that during the loading process of fruits and vegetables into the cold storage, increasing the spacing of new loading goods could reduce non-uniformity coefficient fluctuation range of temperature. But almost the same value of non-uniformity coefficient of temperature was obtained at the spacing of 0.8 and 0.5 m, which meant that the loading spacing was not the larger the better. The larger loading spacing would increase additional workload for settling apples. Thus, there existed a reasonable small space to ensure the storage quality of goods. Pre-cooling could be helpful to reduce the goods' cooling load. When the loading temperature was decreased from 281.15 to 276.15 K, the maximum value of non-uniformity coefficient of temperature was reduced by 50.3%. The impact of loading quantity on indoor thermal environment was also investigated with 5%, 10% and 15% of storage amount, respectively. When the loading quantity was decreased from 15% to 5%, the maximum cooling time was reduced by 23 h and the maximum value of non-uniformity coefficient of temperature was reduced by 73.7%. The reasonable loading measure should be "small quantity and multiple batches" which can effectively reduce the goods cooling load and the cooling time for the practical operation and management of the cold storage. For the cold storage, the reasonable loading condition is proposed to be 3℃ for loading temperature, 0.5 m for loading spacing and less than 10% for loading quantity.