白通通, 南晓红, 金宝红, 初正鹏. 竖壁贴附送风改善冷藏库内流场特性[J]. 农业工程学报, 2019, 35(22): 331-337. DOI: 10.11975/j.issn.1002-6819.2019.22.039
    引用本文: 白通通, 南晓红, 金宝红, 初正鹏. 竖壁贴附送风改善冷藏库内流场特性[J]. 农业工程学报, 2019, 35(22): 331-337. DOI: 10.11975/j.issn.1002-6819.2019.22.039
    Bai Tongtong, Nan Xiaohong, Jin Baohong, Chu Zhengpeng. Improvement on characteristics of air flow field in cold storage with vertical wall attached ventilation[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(22): 331-337. DOI: 10.11975/j.issn.1002-6819.2019.22.039
    Citation: Bai Tongtong, Nan Xiaohong, Jin Baohong, Chu Zhengpeng. Improvement on characteristics of air flow field in cold storage with vertical wall attached ventilation[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2019, 35(22): 331-337. DOI: 10.11975/j.issn.1002-6819.2019.22.039

    竖壁贴附送风改善冷藏库内流场特性

    Improvement on characteristics of air flow field in cold storage with vertical wall attached ventilation

    • 摘要: 果蔬贮藏期间,冷藏库内的气流分布是影响果蔬贮藏品质和送风能量利用率的关键因素,合理的气流组织对冷藏库内流场分布是至关重要的。该研究以某苹果冷藏库为研究对象,采用竖壁贴附送风方式,并对其流场建立了三维稳态的SST湍流模型来研究库内流场的分布特性以及货物的冷却效果,同时与传统的冷风机直吹送风的流场特性进行了对比。结果表明:在相同送风量下,相比冷风机直吹送风方式,竖壁贴附送风使得库内温度不均匀系数和速度不均匀系数分别降低了31%和47%。而且竖壁贴附送风使库内空气与货物的换热更加充分,进而使得送风的能量利用率提高了19%。因此,竖壁贴附送风方式应用于冷藏库是一种有效且节能的气流组织方式。

       

      Abstract: Abstract: During the storage of fruits and vegetables, the uniformity of air distribution inside the cold storage store is crucial to affect both the storage quality of fruits or vegetables and energy efficiency of supply air. In the traditional cooling fan direct blowing air supply mode, some local air velocities and temperatures are easily to be larger than those required for cargo area, which would greatly reduce the uniformity of air distribution and the storage quality of fruits and vegetables. Therefore, the reasonable airflow organization is critical to the air distribution of the cold storage and must be carefully considered. In order to improve the uniformity of indoor air distribution, the study introduced the vertical wall attached ventilation which originated applied for indoor climate control of public buildings. To investigate the flow characteristics of the vertical wall attached ventilation, a three-dimensional SST k-ω solution model was established to study the distribution characteristics of the flow field and the cooling effect of the stored cargo. According to the practical array of the stored apples, the cargo area was regarded briefly as porous medium zone. In order to ensure the accuracy of the numerical calculation and the rationality of the mathematical model, grid independence verification and experimental verification were carried out. The accuracy of numerical calculation was studied by comparison with some accepted correlations and the rationality of the mathematical model was proved. The velocity distribution and temperature distribution of typical sections were monitored to illustrate the air flow pattern and temperature distribution characteristics under the vertical wall attached ventilation mode. Meanwhile, compared with the traditional air supply by cooling fan for direct blowing, it was clarified that the vertical wall attached ventilation could form a more uniformly temperature distribution and velocity distribution on the monitoring section and monitoring line. However, the air distribution of monitoring section and monitoring line could not fully reflect the overall temperature and velocity distribution inside the cold storage. Furthermore, the air distribution evaluation index was introduced and calculated in order to fully understand the temperature distribution characteristics of the studied cold storage room. First of all, in order to reflect the uniformity of air distribution, the non-uniformity coefficient of temperature and non-uniformity of velocity were introduced. According to the temperature and velocity values of 40 measuring points in each stack, the velocity non-uniformity coefficient and temperature non-uniformity coefficient were calculated under two air distribution modes. It was manifested that the vertical wall attached ventilation enabled non-uniformity coefficient of temperature and non-uniformity of velocity to decrease by 31% and 47%, respectively at the same air supply flow rate and temperature. Secondly, to evaluate the energy utilization of the air supply, the energy utilization efficiency of the two modes was calculated from monitoring air supply temperature, air return temperature and average temperature in the cargo area. It was indicated that the vertical wall attached ventilation made the energy utilization increase by 19% due to the more sufficient heat exchange between the air and cargo. Since the vertical wall attached ventilation can form a more uniform air distribution under a higher energy utilization rate, it can effectively improve indoor air distribution characteristics and well meet the storage requirements of fruits and vegetables.

       

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