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1、编号：时间：2021年x月x日书山有路勤为径，学海无涯苦作舟页码：第1页 共1页Int. Agrophysics, 2001, 15, 247-254 INTERNATIONALAgrophysicswww.ipan.lublin.pl/int-agrophysicsEffect of the triticale grain moisture content on the spontaneous heating of grain and on the pressure against the silo wall E. Kusinska Department of Engineering and
2、 Machinery,University of Agriculture, Doswiadczalna 44, 20-236 Lublin Received October 9, 2000; accepted May 29, 2001 Abstract.The author presents the results of studies on the temperature and horizontal pressure of triticale grain in a model silo. The studies included grain with an initial moisture
3、 content of 13, 16 and 18% w.b. The grain storage duration was 25 days. The study showed that grain temperature is affected by its initial moisture content. The highest temperature values were observed in grain with an initial moisture content of 18% w.b. Also, a higher initial moisture content resu
4、lts in greater increases in pressure. Keywords: triticale, moisture content, silo, heating INTRODUCTIONTemperature and moisture content are the most important factors affecting grain quality in the course of its storage. Seasonal and diurnal variation in temperature have a negative effect on stored
5、grain, cause water migration and changes in its distribution within the material stored. The accurate prediction of moisture content and the temperature of grain in storage is necessary for the effective control of the process of ventilation, applied to provide optimum storage conditions for grain a
6、nd the minimizing of conditions for infestation by insects 2. The free migration of water depends on a number of factors -the kind and quality of grain in storage, the size and shape of the grain, its temperature, initial moisture content, and atmospheric conditions. It also depends on the duration
7、of storage, as well as on the sorptive and diffusive properties of the grain. Those factors cause the process of water migration to be unstable. Water tends to migrate from warmer to cooler areas within grain mass. The migration rate is faster in grain with a higher moisture content than in dry grai
8、n 10. EFFECTS OF WATER MIGRATION IN PLANT MATERIALSNumerous authors have tried to describe the phenomenon of water migration. Holman and Carter 10 studied the process in over a dozen soybean varieties with different bean sizes. They showed that water migration takes place in all soybean varieties, w
9、hich results from water accumulation in higher layers of material in storage. Schmidt 19 conducted experiments involving measurements of the wheat grain moisture content during storage. He found that water migration generally begins in the second half of September or at the beginning of October. Hel
10、levang and Hirning 9 performed a study on 16 varieties of beans of various sizes during the period from April to August. They observed an average moisture content drop by 2.56% in the upper layer and a 0.45% increase in the layer located 0.6 to 1.8 m below. Knowledge of changes occurring in the cour
11、se of cereal grain storage is very important for practical purposes. The application of a suitable model for the calculation and determination of the quantitative and qualitative distribution of water and temperature within the grain mass in storage, the grain being a commercial commodity, can help
12、the proper storage of various cereals under a variety of climatic conditions. A numerical model for the calculation of water migration within grain mass in storage has been developed by Khankari 11. He derived non-linear equations describing the temperature, moisture and rate of free convection, usi
13、ng current weather data. The numerical model for the calculation of water migration was used for the calculation of temperature and moisture distribution in grain, for conditions prevalent in Minnesota. The model was based on the assumption that natural air convection is the prevalent phenomenon wit
14、hin grain mass. The mathematical model was then tested experimentally 13. For the tests, Khankari used a cylindrical silo, 10 m high and 10 min diameter, in which he stored maize grain with an average moisture content of 14% at an average temperature of 25C for the period of one year, beginning from
15、 October, without ventilation. Values of thermal conductivity calculated by means of the model conformed to the results of the experiment. Khankari et al. 12 also gave the values of the other parameters of diffusion for maize grain. They found that water migration increases with increasing temperatu
16、re. During the initial period of storage, i.e., during the autumn rainy period and early winter, water migration is limited to areas close to the silo walls. The effect of natural convection on water flow appears at the end of December and at the beginning of January, when temperatures reach the maximum levels. Therefore, water migration rate is the fastest in winter. The studies showed that the increased therm
