شبيه سازي عددي فرايند انتقال حرارت ماكروويو در صنايع غذايي

چكيده انگليسي :

mathematical simulation of heat transfer process in the food industry Faramarz Kahbandeh f kahbandeh@me iut ac ir Date of Submission 2017 01 11 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor ahmad saboonchi ahmadsab@cc iut ac irAbstract Identify and control the process temperature changes and homogeneous distribution in a heating orcooking process is particularly important in the final quality of the product Therefore solving equationsand finding identical and homogeneous temperature distribution that can accurately predict these changes contributed greatly to this issue In previous research solving equations and factors of food is thoroughlyinvestigated Factors that affect how the heat transfer is achieved for various foodstuffs In the design ofhousehold microwave ovens geometry not considered to more homogeneous and faster increase distributionof temperature food In this study In addition to predict temperature distribution in various foods inhousehold microwave studied geometry suitable for the microwave heated combined with direct heattransfer is investigated In the present work according to the need and the lack of analytical solution ofequations finite element method has been used for discretize equations which Comsol commercialsoftware is used Simulation Microwave ovens for two and three dimensional geometry simulation was conducted comparing the results of two and three dimensional geometry was observed that the two dimensional modelresults are totally unacceptable In a three dimensional model results compared with experimental data andgood agreement is observed for numerical and experimental the maximum error of 5 percent was observed By comparing the different modes of grid grid size of a quarter wave amplitude results were independent ofthe grid According to internal generation of heating food in microwave Convection heat transfer from fooddid not has any effect on calculation The average maximum temperature in addition to reducing cooking time also creates a favorable quality In addition to reducing cooking time homogeneous temperature is important for avoiding raw food incooking Entrance area of electromagnetic waves in different conditions compared and it was observed thatwhen the width of the inlet microwave is equal to the dielectric object maximum average temperature ofthe object is created With increasing area of opening more than size of dielectric body temperaturedistribution will be more heterogeneous But in the case of a dielectric body height if the height of the inletwas equal with the dielectric body heigh the most homogeneous temperature is created which is also thedesired mode In microwave cooking it was shown that in higher temperature imaginary part of dielectric property willincrese and it means dielectric material lose more waves and got warmer For having more efficency inmicrowave heating microwave can be used in combined with heat system In this study combinationmicrowave cooking and direct heat transfer has taken place In this case part of the dielectric body has ahigher temperature compare to the whole object at the beginning of cooking The maximum temperature inmicrowave cooking and combined mode were the same but the average temperature distribution at eachtime step in combined cooking was more than microwave cooking Baking with more homogeneoustemperature distribution is desirable Keywords Microwave Dielectric properties Microwave cooking

كاه بنده، فرامرز

شبيه سازي عددي فرايند انتقال حرارت ماكروويو در صنايع غذايي

خاصيت دي الكتريك , پخت مايكروويو , الكترومغناطيس