Mathematical Modelling of the Heat Transfer and Microbial Inactivation During a Meat Pet Food Sterilization in Retortable Pouches

2012 ◽  
Vol 7 (6) ◽  
Author(s):  
Frampton Franklin Santana ◽  
Pedro Esteves Duarte Augusto ◽  
Marcelo Cristianini
Keyword(s):  
Heat Transfer ◽  
Mathematical Modelling ◽  
Process Evaluation ◽  
Thermal Process ◽  
Food Preservation ◽  
Microbial Inactivation ◽  
Pet Food ◽  
Analysis Model ◽  
Finite Elements Analysis ◽  
Experimental Values

Thermal process is still the most used and safer method for food preservation. Although the mathematical modelling of heat transfer has been used for thermal process evaluation, microbial validation is rarely carried out, and the evaluation of retortable stand up pouch processes were not studied. The present work employed a finite elements analysis model (FEA) for the evaluation of a conductive meat pet food process sterilization in stand up retortable pouches. The results obtained by the model showed good agreement with the experimental values, for both temperature histories and microbial inactivation comparison. The results obtained demonstrate the utility of using mathematical models for describing the heat transfer and microbial inactivation in food thermal process, and reinforce that it can be a powerful tool in food process evaluation and design.

Evaluation of Boundary Conditions for CFD Simulation of Liquid Food Thermal Process in Glass Bottles

2012 ◽  
Vol 7 (6) ◽  
Author(s):  
Pedro Esteves Duarte Augusto ◽  
Marcelo Cristianini
Keyword(s):  
Boundary Condition ◽  
Boundary Conditions ◽  
Temperature Profile ◽  
Thermal Process ◽  
Cfd Simulation ◽  
Convective Heat Transfer Coefficient ◽  
Food Products ◽  
Food Preservation ◽  
Heating Water ◽  
Experimental Values

The growing demand for safer and high-quality food products creates the need for better knowledge of the processes involved in food production. The computational fluid dynamics (CFD) have been widely used to better understand food thermal process, one of the safest and most frequently used methods for food preservation. However, no consistency in mathematical models has been observed, especially on the boundary conditions definition. The present study has evaluated four methodologies for the definition of boundary conditions for heating water in two commercial bottles: (M1) temperature profile of heating water (T∞) and convective heat transfer coefficient (h), (M2) T∞ as boundary condition for the outside package wall, (M3) T∞ as boundary condition for the outside heated liquid edge, and (M4) internal temperature profile (T=T(x,y,z,t)), previously measured in the inner package wall, as boundary condition for the outside heated liquid edge. Models that considered the measured value of h e T∞ as boundary condition showed good agreement with experimental values, compared by thermal history and sterilization value (F). The models that considered the temperature profile of the heating water or the inner package wall as boundary conditions, showed faster heating. By over-estimating the product heating rate, those models are not appropriated for thermal process modelling, as it compromises the safety and preservation of food products.

Determining the Convective Heat Transfer Coefficient (h) in Thermal Process of Foods

2011 ◽  
Vol 7 (4) ◽  
Author(s):  
Pedro Esteves Duarte Augusto ◽  
Marcelo Cristianini
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Thermal Process ◽  
Convective Heat Transfer Coefficient ◽  
Food Preservation ◽  
Thermal Processes ◽  
Water Steam

Thermal processing is the most important and utilized method for food preservation, being those carried out with the food inside the package the most appropriated for safety consumption guarantee. During processing, the packaged food is surrounded by a heat transfer medium, in general a fluid as water, steam, air or its mixtures. Therefore, the definition of the convective heat transfer coefficient (h) is important for several process studies, although the available data is scarce, especially in food thermal processes. Although there is several methods for determining the h values, the non-regular food geometries and transient characteristics of thermal processes, makes difficult using most of the methods. This work aimed to describe an appropriated method to determining the convective heat transfer coefficient (h) in thermal process of foods.

Theoretical Post-Dryout Heat Transfer Model

2018 ◽  
Vol 1 (1) ◽  
pp. 142-150
Author(s):  
Murat Tunc ◽  
Ayse Nur Esen ◽  
Doruk Sen ◽  
Ahmet Karakas
Keyword(s):  
Heat Transfer ◽  
Droplet Diameter ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Operating Pressure ◽  
Vertical Pipe ◽  
Two Phase ◽  
Experimental Values ◽  
Reactor Operating ◽  
Coolant System

A theoretical post-dryout heat transfer model is developed for two-phase dispersed flow, one-dimensional vertical pipe in a post-CHF regime. Because of the presence of average droplet diameter lower bound in a two-phase sparse flow. Droplet diameter is also calculated. Obtained results are compared with experimental values. Experimental data is used two-phase flow steam-water in VVER-1200, reactor coolant system, reactor operating pressure is 16.2 MPa. On heater rod surface, dryout was detected as a result of jumping increase of the heater rod surface temperature. Results obtained display lower droplet dimensions than the experimentally obtained values.

scholarly journals Testing algorithm for heat transfer performance of nanofluid-filled heat pipe based on neural network

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 751-760
Author(s):  
Lei Lei
Keyword(s):  
Neural Network ◽  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Performance ◽  
Volume Fraction ◽  
Heat Pipes ◽  
Transfer Performance ◽  
Analysis Model ◽  
Accurate Analysis ◽  
Testing Algorithm

AbstractTraditional testing algorithm based on pattern matching is impossible to effectively analyze the heat transfer performance of heat pipes filled with different concentrations of nanofluids, so the testing algorithm for heat transfer performance of a nanofluidic heat pipe based on neural network is proposed. Nanofluids are obtained by weighing, preparing, stirring, standing and shaking using dichotomy. Based on this, the heat transfer performance analysis model of the nanofluidic heat pipe based on artificial neural network is constructed, which is applied to the analysis of heat transfer performance of nanofluidic heat pipes to achieve accurate analysis. The experimental results show that the proposed algorithm can effectively analyze the heat transfer performance of heat pipes under different concentrations of nanofluids, and the heat transfer performance of heat pipes is best when the volume fraction of nanofluids is 0.15%.

Mathematical Modelling of Deciduous Tree Ignition by Ground Lightning Discharge Taking into Account Localization of Reactive Wood

2011 ◽  
Vol 6 (4) ◽  
pp. 95-106
Author(s):  
Nikolay Baranovskiy ◽  
Geniy Kuznetsov
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Mathematical Modelling ◽  
Lightning Discharge ◽  
Deciduous Tree ◽  
Tree Trunk ◽  
Mathematical Statement ◽  
Cylindrical System ◽  
Typical Range

Physical and mathematical statement and results of the numerical simulation of a problem about deciduous tree (birch) ignition by ground lightning discharge are presented. The problem is considered in flat statement in cylindrical system of coordinates. Heat transfer features taking into account localization of reactive wood are considered. The parametrical analysis is carried out and conditions of tree trunk ignition in a typical range of parameters of influence of positive discharges are obtained

Time–Temperature Integrators for Thermal Process Evaluation

2005 ◽  
pp. 597-620
Author(s):  
Antonio Mart√≠nez ◽  
P Fern√°ndez ◽  
D Rodrigo ◽  
M Ocio
Keyword(s):  
Process Evaluation ◽  
Thermal Process
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