Mechanism Study Of Heat Conduction In The Biological Fermentation Bedding

This thesis analysis the mechanism and regularity of heat conduction,to provide a reference to address the fermentation bed management problems in the bio-fermentation pigs cultivation technology.First by bonding theory of heat transfer,analysis the hierarchical structure of the bedding,combined with the actual cultivation conditions,the heat transfer process inside the bedding were analyzed,and take the issue of the bedding system as a steady-state heat conduction for studying.Followed by the experimental determination of the physical parameters of the bedding parts.As pores exist inside the bedding,we can consider bedding as a porous medium.The presence of water and air in the pore,such bedding structure determines the thermal conductivity will vary as porosity and moisture content varies.Using heat transfer knowledge,the temperature distribution formula of bedding model is deduced.The next step,using software ANSYS to build three-dimensional physical model of laboratory bedding,the internal temperature distribution of bedding in a specific fermentation temperature is calculated.By comparison and analysis,we have the results as follow:As the presence of a heat source,the temperature inside the bedding has a descending process from the center to the edge.In the range of 30-80?,the temperature distribution is substantially the same tendency.Establishing a bedding model in the laboratory,select a specific bedding matrix composition,use hot plate heated simulated fermentation temperature,measure the changes within the bed and bedding mat surface temperature in different fermentation temperatures.1.The internal temperature and ambient temperature of the bedding have the same trend,but showed lag.In the transmission of the bedding,the temperature on the center axis higher than the temperature of the edge.2.The temperature difference in the interior of the bedding measurement points closely related to the surrounding environment,the internal temperature higher than ambient temperature.3.Under natural conditions the surface temperature distribution of bedding is generally even.When there is heat source,the surface temperature will be affected by the fermentation temperature and rise,but the effect is not obvious.Model simulation of steady state heat conduction point temperature did not significantly different from the point temperature in the experiment measured,only a slight difference made,indicating that the model is reliable.Through theoretical analysis,research and numerical simulation combination,heat transfer mechanism inside the bedding is systematically studied,which laid the theoretical foundation for the promotion of bio-fermentation pigs cultivation technology,and has certain reference value for fermentation bed research of combination of different litter.