Uniform TitleNumerical simulation of thermal transport in a high hydrostatic pressure food processing vessel
NameKhurana, Meenakshi (author), Karwe, Mukund (chair), Yam, Kit (internal member), Takhistov, Paul (internal member), Jaluria, Yogesh (internal member), Rutgers University, Graduate School - New Brunswick,
DescriptionHigh Hydrostatic Pressure Processing (HHPP) is a novel non-thermal food processing technology for producing safe, high quality food products, with minimum detrimental effects of thermal processing such as loss of original flavor and color. The high pressure range used for processing food products is 100 to 1000 MPa. Clams are high pressure processed in the range of 200-350 MPa and fruit juices between 300-600 MPa. Spores, found mainly in low acid foods, and prions need even higher pressures for inactivation.
When pressure is applied on a food product using liquid medium, adiabatic heat generation occurs due to compression of the pressurizing medium and the food product, which results in increase in their temperatures. This increase in temperature is different for different foods. For example, water heats up by 2-3°C per 100 MPa increase in pressure. Oils and fats heat more (6-9°C) due to their higher compressibility, lower thermal conductivity, and lower heat capacity.
In a high pressure process, the heat generated by adiabatic compression is continuously dissipated to the thick metal wall of the vessel during pressurization and pressure hold stages. The heat loss at the wall and the natural convection flow near the vessel wall give rise to non-uniform temperature distribution within the pressurization medium. Therefore, the objective of this research was to carry out numerical simulation of thermal transport in pressurizing medium (water) during HHPP (at room temperature and higher initial temperature) to predict the temperature distribution. Numerical predictions were validated using experimental data. The impact of the response time of the high pressure thermocouple assembly on the measured transient temperature response was taken into account.
Results obtained from the numerical simulation showed that the temperature distribution in the pressurizing medium became non-uniform during the high pressure process and this non-uniformity increased with increasing initial temperatures. Also, increasing the vessel size and inserting an insulating sleeve in the vessel decreased the non-uniformity in temperature.
Non-uniformity in temperature in the pressurizing medium can lead to non-uniform microbial inactivation and is of most relevance when a combination of high pressure and high temperature is used to inactivate spores.
NoteIncludes bibliographical references (p. 101-106).
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.