| Maize is one of the important merchandise grain of our country. Because Jilin province lies north of China, the harvest-time of maize is almost in October when the weather temperature begins to decline .The moisture content of maize is general about 25%-30%,some even reach 36%.In order to enhance income and soil output, more and more peasants begin to plant high yield and late mature maize neglecting the weather that the maize requires. For this reason ,the maize is nont total ripe in October and the moisture content is very high. This kind of maize is not safe for storage and long-distance transportation. It is necessary to desecrate this kind of maize by drier to reach the safe moisture content.For dire maize ,both appearance and inner quality exist difference, the drying equipment being used are mostly traditional equipments which is only intent on reduce moisture and neglecting the criterion of control quality. Such as umber grain, crack rate, crash rate and so on.With the opening of farm produce market in our country. The maize quality is becoming one of the important problems that affect the quality of dried maize and the crack rate is an important one. According to some materials, the crack rate increases the crash rate during the transportation, decreases the quality rate of maize and affects the economy income. From 60s a lot of experiments and theory analysis have been made on the maize crack during frying process by west countries. They also established some relative criteria for crack rate. While in our country there is a few study in this field and mostly limit in theory study so that it can not instruct people's practice. In practice, in order to reduce stress crack to minimum, we need choose fine drying parameters in order to satisfy the requirement of moisture reduction and the minimal stress crack rate.In recent years, there were some reports about the mathematics model of corn drying model, but most of them were concentrate on how to found a theory model. There were very little study on the produce practice, especially on considering more factors and more level condition. Experimentation used method of the combination design of orthogonal rotating. Regarding five main corn drying technology parameters (grain depth (x1), drying time (x2), hot air temperature (X3), hot air velocity (X4), reprieve time (x5) as decisive varieties. We study the effect on drying character of corn of differ original containing water rate under effect of five factors we mentioned, understanding the five factors' affect. Ensure the demand rang of moisture reduction choose the fine drying technology parameters, in this way can we provide the reference evidence for the theory design.The method of the combination design of orthogonal rotating regression can predigest experiment times, optimize manufactured ethnics parameters, and provide reference evidence for produce practice and theory design.Through analyzing each factor ,we can definitude every factor's influence trend and work out the contribution rate to moisture reduction of different original moisture content.When the original moisture content is 24%,the order is hot air temperature, grain depth, drying time, hot air velocity, reprieve time. When the original moisture content is 30%,the order is grain depth, hot air temperature, drying time, hot air velocity, reprieve time.We can conclude from every factor's contribution rate to moisture reduction that when the corn's original moisture content is low, the drying time has a greater affection for the range of moisture reduction. With the increasing of the original moisture content, grain depth and hot air temperature gradually become the main factors. That affect the range of moisture reduction. When the corn having a lower original moisture content is dried, the water's humidity grads that diffuse outwardly is weak. We must increase the temperature of hot air to increase temperature grades, accelerate heat exchange between air and corn. Grain depth is a main factor that affects air heat exchange and it di...
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