间断热辐射对钢板仓中稻谷温度和水分影响的模拟研究

SIMULATED THE EFFECT OF INTERMITTENT HEAT RADIATION ON THE TEMPERATURE AND MOISTURE CONTENT OF PADDY IN A STEEL BIN

运用远红外电热幕对装有0.8m3稻谷的钢板仓进行热辐射,研究太阳辐射对钢板仓中粮温传递的影响。稻谷初始湿基水分含量为14.75%±0.35%,辐射时控制模拟仓辐射面温度分别为30℃、45℃和60℃,每个条件试验周期为6d,辐射时间为8:00到20:00。结果表明,距辐射面相同粮层温度上升速率随辐射温度上升而增大;相同辐射条件下升温速率随粮层厚度增大而下降。距辐射面5cm和15cm粮层受环境温度影响,粮温白天上升夜间下降;25cm、35cm和55cm粮层在整个试验过程中粮温持续缓慢上升;75cm粮层从第36h开始温度缓慢上升,相同辐射条件下不同粮层升温速率差异性显著(p<0.05)。拟合得到时间(T)和粮层厚度(S)的二元二次粮温上升速率方程:V=a-bT-cS+dT2+f(T-72)(S-0.35)-g(S-0.35)(T2-6336),a、b、c、d、f、g为常数,R2≥0.832,该方程可预测不同时间、不同粮层厚度的升温速率。

Paddy temperature significant increase in a steel bin and then leads to the deterioration of paddy quali- ty, this can happen easily due to the high solar radiation in summer of several major paddy producing prov- inces in China. To study the effect of solar radiation on the transfer of grain temperature in a steel bin, far infrared electric heating curtain were used to make thermal radiation for a steel bin with 0.8m^3 paddy. Initial wet basis moisture content was 14.75%＋0.35% of the paddy was used for the experiment, the tem-perature of the radiating surface was controlled to 30℃, 45℃ and 60℃ respectively during the period of radiation, 6 days were set as the test cycle for each condition, 8 ： 00 to 20 ： 00 was set as the radiation time. The results showed that the temperature rising rate of the same layer increased with the increasing of the radiation temperature; the heating rate decreased with the increasing of the paddy layer thickness under the same radiation conditions. The temperature of 5cm and 15cm paddy layers away from the radiating surface increased during the day and decreased at night because of the influence of ambient temperature; the tem- perature of 25cm, 35cm and 55cm paddy layers continued to slow rising in the whole test process; the tem- perature of 75cm paddy layer rose slowly from the first 36 hours of the start of the experiment. The tem- perature rising rate of different grain layers was significantly different under the same radiation condition （p〈0.05）. About Time （T） and paddy layer thickness （S） of binary quadratic paddy temperature rise rate equation： V=a-bT-cSnt-dT^2＋f （T-72） （S-0.35）-g（S-0.35） （T^2- 6336） was obtained by fitting, in the equation a, b, c, d, f, g were constants, R^2≥0. 832, the equation to predict the rate of temperature rise at different times, different paddy layer thickness.