Temperature non-uniformities and risk of overheating at a direct ohmic heating of foods

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F08%3A00217257" target="_blank" >RIV/68407700:21220/08:00217257 - isvavai.cz</a>

Výsledek na webu

<a href="http://bulletin-am.cz/index.php/vam/article/view/92/89" target="_blank" >http://bulletin-am.cz/index.php/vam/article/view/92/89</a>

DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Temperature non-uniformities and risk of overheating at a direct ohmic heating of foods

Popis výsledku v původním jazyce

This paper is concerned with temperature non-uniformities especially the estimation of the risk of runaway and overheating at direct ohmic heating of food. The runaway criterion Rw, reflecting the role of temperature dependent electric conductivity and thermal resistance, is suggested. The influence of cooling, singularities at electrodes and fouling layer are analyzed, assuming properties of typical food materials (meat, milk) and typical process parameters. Results indicate that the risk of runaway ata very fast heating can be reduced by cooling a part of surface perpendicular to the intensity of electric field (cooled electrodes). It is further shown, that even if a small irregularity of the electrode surface (e.g. natural roughness) has a strong effect on the local intensity of electric field, temperature effects are seen only if the height of irregularities is comparable with the distance of electrodes (>5%). On the other hand, even very thin fouling layer at an electrode causes

Název v anglickém jazyce

Temperature non-uniformities and risk of overheating at a direct ohmic heating of foods

Popis výsledku anglicky

This paper is concerned with temperature non-uniformities especially the estimation of the risk of runaway and overheating at direct ohmic heating of food. The runaway criterion Rw, reflecting the role of temperature dependent electric conductivity and thermal resistance, is suggested. The influence of cooling, singularities at electrodes and fouling layer are analyzed, assuming properties of typical food materials (meat, milk) and typical process parameters. Results indicate that the risk of runaway ata very fast heating can be reduced by cooling a part of surface perpendicular to the intensity of electric field (cooled electrodes). It is further shown, that even if a small irregularity of the electrode surface (e.g. natural roughness) has a strong effect on the local intensity of electric field, temperature effects are seen only if the height of irregularities is comparable with the distance of electrodes (>5%). On the other hand, even very thin fouling layer at an electrode causes

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

GM - Potravinářství

OECD FORD obor

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Projekt

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Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2008

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Bulletin of Applied Mechanics

ISSN

1801-1217

e-ISSN

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Svazek periodika

4

Číslo periodika v rámci svazku

14

Stát vydavatele periodika

CZ - Česká republika

Počet stran výsledku

7

Strana od-do

74-80

Kód UT WoS článku

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EID výsledku v databázi Scopus

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