外热源对立筒仓粮堆渗流通风控温系统性能影响的试验研究

Experimental research on the influence of external heat source on the performance of the seepage ventilation and temperature control system of silo grain bulk

为阐明太阳辐射对本研究所建立的粮堆渗流通风控温系统性能的影响,采用试验方法对具有仓顶外辐射热源的粮堆渗流通风控温过程进行监测分析。试验结果表明:在渗流通风控温过程中,提高通风量可强化粮堆上方空气层的隔热效果;通风量增大后,具有仓顶外辐射热源时高效降温段时长显著增加;渗流通风控温系统对粮堆外皮的控温效果优于粮堆内芯,具有仓顶外辐射热源时该现象更为显著;通风量由28.26m^(3)/h增大至35.95m^(3)/h时,具有仓顶外辐射热源的时粮堆外皮和内芯温度分别降低了1.56和0.70℃,无仓顶外辐射热源时下粮堆外皮和内芯温度分别降低了0.30和0.08℃,在有仓顶外辐射热源工况下增大通风量可提高粮堆渗流通风控温系统的局部控温性能。实际应用过程中,该系统日间应以低通风量运行,用以隔断外界传热;夜晚应以高通风量运行,用以降低粮堆温度。

In order to clarify the influence of solar radiation on the performance of the seepage ventilation and temperature control system of grain bulk established in this study,the seepage ventilation and temperature control process of grain bulk with radiation heat source outside the silo roof were monitored and analyzed by experimental method.The results show that:Increased ventilation can strengthen the heat insulation effect of air layer above grain bulk during the process of seepage ventilation and temperature control;With the increase of ventilation rate,the duration of high efficiency cooling section increases significantly under the condition of radiant heat source outside the silo roof;The temperature control effect of the seepage ventilation and temperature control system on the skin of the grain bulk is better than that of the core of the grain bulk,and this phenomenon is more significant when there is a radiant heat source outside the silo roof;When the ventilation rate increased from 28.26 m^(3)/h to 35.95 m^(3)/h,the temperatures of the outer skin and inner core of the grain bulk with external radiant heat source on the silo top decreased by 1.56 and 0.70℃,respectively.The temperature of the skin and core of the grain bulk without external radiant heat source on the silo top decreased by 0.30 and 0.08 ℃,respectively.In conclusion,increasing the ventilation rate in the working condition with radiant heat source outside the silo roof can improve the local temperature control performance of the grain bulk seepage ventilation and temperature control system.In the actual application process,the system should be operated with low ventilation in daytime to isolate external heat transfer,and with high ventilation at night to reduce the temperature of grain bulk.