MATHEMATICAL MODELING OF HEAT TRANSFER IN THE WORKING ZONE OF A FLOUR MILL ROLLER
DOI:
https://doi.org/10.32718/agroengineering2025.29.161-165Keywords:
thermal contact zone, temperature distribution, flour mill roller, Peclet number, heat transfer, analytical modeling, roller cooling, thermal regime, mechanical grinding of grain, energy efficiencyAbstract
The article presents an extended analytical and numerical study of heat transfer processes occurring in the working zone of a flour milling roller, where intensive and spatially non-uniform heat generation arises during the interaction between the grain mass and the metallic roller surface. It is demonstrated that heat produced by friction, plastic deformation, and partial fracture of grain accumulates within the contact region and strongly determines the temperature rise on the roller surface, ultimately influencing product quality. Based on Jaeger’s classical theory of moving heat sources, an analytical model is developed to describe the temperature distribution in dimensionless coordinates, enabling the application of the results to rollers of various sizes and structural configurations. The influence of the Peclet number, thermal conductivity, geometric characteristics of the contact zone, and heat flux intensity on the formation of the temperature field is analyzed in detail. The study shows that the maximum temperature occurs near the trailing edge of the contact zone, where the cumulative thermal effect is the strongest. Increasing the Peclet number reduces the peak temperature, yet considerably extends the downstream heated region, reflecting a shift in the balance between heat diffusion and roller surface velocity. Numerical simulations based on double integration of the heat-release distribution validate the analytical model across a wide range of milling regimes. The effectiveness of internal liquid cooling is investigated, revealing that it reduces the average temperature but provides only limited mitigation of local overheating within the contact area. Several strategies for improving thermal management are proposed, including pre-cooling of the grain, optimization of rotational parameters, and the use of localized high-intensity cooling methods. The results obtained contribute to improving the thermal stability, operational efficiency, and product quality in roller milling systems.
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