Heat Pump-high Voltage Electric Field Combined Drying Airflow Organization Simulation And Drying Characteristics Researc

Drying is an energy-intensive process,and the current trend is to encourage the use of more energy-efficient drying technologies from a policy perspective.Heat pump drying is an energy-saving drying method that requires less energy than traditional drying methods.However,in the heat pump drying process,if the temperature is too high,it can increase energy consumption,reduce system performance,and lower drying quality.This article cleverly combines heat pump drying system with electrichydrodynamics to dry materials,which can not only improve drying rate and quality but also reduce drying temperature,shorten drying time,and lower drying energy consumption.A study on the combined drying of heat pump and electrichydrodynamics using carrot slices as a representative of thermosensitive materials,and the main research work and results are as follows:（1）The physical field in the heat pump-electrohydrodynamics drying chamber was comprehensively numerically simulated and analyzed by simulation.The results showed that the uneven coefficients and ranges of variation of the material air speed under upper supply and bottom return mode were about 93.3%-94.3%and 81.6%-82.9%lower than that under the intermediate supply and intermediate return mode,respectively.The uneven coefficients and ranges of variation of the temperature under upper supply and bottom return mode were about 97.0%-97.8%and 72.6%-75.7%lower than that under the intermediate supply and intermediate return mode,respectively.（2）The effects of adjusting the drying temperature of heat pump,the voltage of electrichydrodynamics,and the supply and return air modes on the drying rate and energy consumption were studied.The results showed that combined heat pump-electrichydrodynamics drying could effectively reduce the drying temperature of heat pump,reduce specific energy consumption,and shorten drying time.This has significant research significance for thermosensitive materials.The drying time of the combined drying under the supply and return air mode was about 16.67-26.32%shorter than that of the single heat pump drying at the same temperature.As the voltage increased,the effective moisture diffusion coefficient(D_eff)also increased.The effective diffusion coefficient at 100 kV was about 1.2-1.5 times higher than that of the single heat pump drying at the same temperature.In the thermodynamic analysis,the enthalpy change（ΔH）gradually decreased with the increase of temperature and voltage,indicating that less energy was required for the drying process.Under the supply and return air modes,the averageΔH of the combined drying were 41.91%lower than that of the single heat pump drying.（3）The drying mathematical models were used to fit the moisture content curve of carrot slices during drying.The results showed that the improved model proposed in this paper,MR=aexp（-（kt）ⁿ）.It had an R² value range of 0.99996-1 under different conditions,indicating that it was the best model.This can also be seen from the verification of experimental and simulated values,showing that the model could well describe the variation of moisture content.（4）The content ofβ-carotene in carrot slices under different drying conditions was determined and qualitatively analyzed.The results showed that the contents ofβ-carotene were higher at lower temperatures,and gradually decreased with the increase of temperature at each voltage.The overall contents ofβ-carotene during upper supply and bottom return drying were higher than that during intermediate supply and intermediate return.This study aims to provide practical guidance for the application of heat pump-electrohydrodynamics combined drying system to thermosensitive materials,and optimize the process of drying carrot slices using heat pump-electrohydrodynamics.