Research On Multi-fields Coupling Model Of Wheat Grain And Condensation Prediction

Grain storage safety is very important. The grain is living body. The influence factors ingrain storage ecosystem are abundant, however the change process of the grain bulk statuscouldn’t be described precisely by researching on only one factor. Otherwise, thecondensation is a critical factor which is related to grain storage status. The temperature,humidity, micro-airflow and equilibrium moisture content of grain are the importantinfluencing factors of condensation. So, to study the condensation mechanism, themulti-coupling fields which are described by constructed models could predict the change ofgrain status and provide theoretical basis for laying down effective regulation measures torealizing safe grain storage.In the paper, the multi-coupling theory is used and the multi-fields coupling model ofthe wheat bulk is established. Thus, the process of grain condensation can be simulated andpredicted by them.1. The change process of wheat bulk condensation was simulated by the multi-fieldscoupling theory. A mini grain micro-airflow observation experimental facility (GMAOEF)and a1m3small grain condensation simulation study platform (GCSSP) were designed andestablished. The micro-airflow velocity of wheat test, wheat bulk condensation simulationexperiment and related to tests were done. They could offer data support for the multi-fieldscoupling model construction.2. The physical parameters, such as equivalent diameter, porosity of the wheat and soon, were measured. Then the water transport pathway, heat and humidity transmissionmechanism of grain bulk were known. As hygroscopic and unsaturated porous media, thewheat multi-fields coupling model was built by adding buoyancy as well as WU model.3. The wheat condensation process in certain temperature difference was simulated bybuilt model. The position and time of wheat bulk condensation were obtained by model. Theresults were the same with reproduced results and experiment results.4. The wheat bulk state of Dongli grain reserves depot in Tianjin City, North ChinaDistrict was described by model. The simulation results were verified. Therefore the positionand time of wheat bulk condensation could be done by multi-fields coupling model.The research results showed that the grain storage status could be obtained bymulti-fields coupling theory, the position and time of grain bulk condensation could bepredicted precisely by the multi-fields coupling model of the wheat bulk. It would lay thefoundation for biological fields influence on grain storage ecosystem.