Anomalous Behavior of Liquid-Nitrogen Drops in Film Boiling

Baumeister, K. J.; Keshock, E. G.; Pucci, D. A.

doi:10.1007/978-1-4757-0244-6_55

Cited by 6 publications

(2 citation statements)

References 2 publications

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“…Evaporation of individual liquid nitrogen droplets on a metal plate was studied by Keshock & Bell (1970), Baumeister, Keshock & Pucci (1971), Schoessow, Chmielewski & Baumeister (1978). Hassan (1981) and Awonorin (1982) measured evaporation times and droplet size in contact with food.…”

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Heat transfer coefficient for nitrogen droplets film‐boiling on a food surface

Awonorin

Lamb

1988

Int J of Food Sci Tech

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A method of measuring heat transfer rates from a solid food surface to liquid nitrogen droplets on it has been developed using 0.5 sec repeat-shot photography. Droplet diameters were varied from 0.1 to 2.5 mm and food surface temperatures from +30 to -100°C. All measurements were carried out at atmospheric pressure.The mean heat transfer coefficients were determined using an energy balance for the droplets. An empirical dimensionless correlation equation was established, and the significance of the results for food freezing by liquid nitrogen sprays is critically discussed. KeywordsHeat transfer rates, liquid nitrogen food freezing, nitrogen droplets.

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confidence: 99%

Heat transfer coefficient for nitrogen droplets film‐boiling on a food surface

Awonorin

Lamb

1988

Int J of Food Sci Tech

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“…They attributed this increase to the shorter vaporization times of droplets, vapour instabilities, low latent heat of vaporization and convection effects. Baumeister, Keshock and Pucci (1971) further developed expressions for the heat transfer coefficient by taking account of the latent heat of vaporization for liquid nitrogen, but the measured vaporization times were still lower than those predicted theoretically. Schoessow, Chmielewski and Baumeister (1978) concluded that contamination of nitrogen by ice at the early stages of droplets' formation, and convection effects account for approximately 20% of the vaporization times.…”

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confidence: 95%

A model for heat transfer in cryogenic food freezing

Awonorin

1989

Int J of Food Sci Tech

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An experimcntal study of the heat transfer between liquid nitrogen sprays and a model food (a gelatine slab) was carried out under conditions similar to those in a cryogenic freezer. Measurements of heat flux and local mass flow rates of the spray were made at various liquid N2 pressures and various temperature differences between the spray and the food surface.At higher spray pressures, the heat transfer doefficient increases with the mass flux density of the liquid available at the food surface. The quantity of liquid nitrogen sprayed onto the solid surface, the mean droplet size, spray velocity, surface coverage and the mean temperature difference between the boiling nitrogen and the food surface are major factors influencing the rate of heat transfer during the freezing process. Although the heat transfer coefficients at the food surface are much less than those obtained for individual droplets, the model provides useful data.The results are critically discussed in relation to cryogenic freezing of foods.

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