亞熱帶散裝稻穀倉儲通風作業熱質傳速率之研究

Study on the Heat and Moisture Transfer Rates of Aerating Rough Rice in Bulk Storage

陳加忠(Chia-Chung Chen)

《農業機械學刊》 7卷1期 (1998/03) Pp. 1-19

https://doi.org/10.30062/JAM.199803.0001

摘要

在美國與歐州等溫帶氣候國家，利用低溫低溼的大氣進行通風可降低穀物溫度，並有部份幹燥效果，在亞熱帶氣候，由於大氣相對溼相當高，利用高溼空氣進行通風對穀物之影響需要加以研究。Banks曾推導多孔隙性吸溼介質之熱傳與質傳現象，以探討溫度與水份傳遞速率。在此研究中採用其原理並加以修正，將其模式假設條件依實際通風作業之情況加以改良。由此建立數組方程式以量化通風倉內溫度與水份之鋒面運動現象，並利用國內稻穀品種的平衡含水率模式以改良模式之準確性。試驗設計包括溫度與水份鋒面運運動之量影響。其影響因包括大氣的溫度與溼度，穀物的溫度與含水率，及通風量等。一具小型通風試驗倉用以裝填稻穀以模擬穀倉，並利用微氣候控制箱以代表大氣狀況。在各種通風狀況下收集的實驗數據用以改良與驗證Banks理論與原建立之方程式。量測數據與已知文獻資料均證實此模式之適用性。此通風模式進行敏感性分析，以建立高相對溼度氣候下的通風策略。而此策略可結合已發展完成之通風設備以執行適切的通風作業。

關鍵字

通風 ； 亞熱帶 ； 溫度鋒面 ； 含水率鋒面

並列摘要

Due the low temperature and relative humidity of atmosphere in temperate region such as USA and Europe, the aeration can cool the grain temperature and result in partly drying effet. Because the relative humidity of ambient air is pretty high in subtropic climate as Taiwan, the study of the aeration effect on grain quality is needed by using ambient air with higher relative humidity. The analysis of heat amd mass transfer in porous hygroscopic media was developed by Banks' to study the temperature and moisture transfer rate. The same theory is adopted and modified in this study. Several equations are proposed to describe and quantify the temperature and moisture movement front in an aerated grain bulk. An ERH/EHC model for the rough rice of local variety was selected to improve the accuracy of this model. Experimental design was proposed to test the temperature and moisture movement front which effect factors include the temperature and relative humidity of atmosphere, temperature and moisture content of grain, and the airflow rates. The small experimental cyclinder bin filled with rough rice was used to simulate the bulk bin. An environmental control chamber was adopted to represent the condition of ambient air. The experimental data were collected to modify and validate the Banks' theory. The measured data and previous information from literatures were adequate to validate model. The aeration model can use to proceed the sensitive analysis and to establish the strategy for ambient air with high humidity air. This strategy can be served as the control sofeware combining with the developed hardware system for proper aeration.

並列關鍵字

Aeration ； Subtropic ； Temperature front ； Moisture front