Precooling of cylindrical food products

SUMMARYIn this paper, the development of new Fourier-Reynolds correlations for determining the cooling process parameters of products subject to air cooling, in terms of the half cooling times and seven-eighths cooling times is presented. The experimental data were taken from the author's previous work, processed and used in the development of new Fourier-Reynolds correlations and diagrams. These Fourier-Reynolds correlations are Fo & "42·465Re\ and Fo 1 "125·21Re\ for half cooling times and seven-eighths cooling times, respectively. The results of this study indicate that there is a strong relationship between the Fourier and Reynolds numbers, and the Fourier-Reynolds correlations and diagrams are simple and effective tools for determining the cooling process parameters for such objects cooled in air flows. It is believed that these could be beneficial to the refrigeration industry.

“…In order to verify the present correlations, the experimental cooling process data taken from Ansari and Afaq (1986) for carrots and Guemes et al (1988) for strawberries are employed.…”

Section: Examplesmentioning

confidence: 96%

New Fourier-Reynolds Correlations for Refrigeration Applications

Dinçer

1997

“…The experimental cooling coefficient values and Nusselt numbers for the products (i.e., tomatoes, pears, cucumbers, figs, and grapes) were taken from the literature (Dincer, 1993). Additionally, some experimental data for bananas and carrots were taken from Ansari and Afaq (1986), and the cooling coefficients were determined according to the methodology mentioned above.…”

Section: ( 3 )mentioning

confidence: 99%

“…( 6 ) Nu = (2.2893 X 10-4Dz'~0047) Banana ( z = 0015 m, Tu = 5.9"C) (Ansari and Afaq, 1986) 6.6 0.001 850 0 6344…”

Section: ( 5 )mentioning

confidence: 99%

See 1 more Smart Citation

Development of a new number (the Dincer number) for forced-convection heat transfer in heating and cooling applications

Dinçer

1996

In this article, a new number is developed for the use of forced-convection transient heat transfer to take place during heating and cooling of any solid object. This is called the 'Dincer number' which indicates the effect of the flow velocity of the surrounding fluid on the heating coefficient or cooling coefficient. It indicates that there is a strong relation between the Nusselt number and the Dincer number. For this reason, an application of this number was made and a new Nusselt-Dincer correlation, namely Nu = (2.2893 X 10-40i"0047 ) w as developed for food products exposed to forced-air cooling using the experimental data sets. It is therefore possible to determine the heat transfer coefficient from the Nusselt number after estimating the Dincer number. It can be concluded that the Dincer number brings a new approach to heating and cooling problems. Owing to their simplicity and effectiveness, development of the Nusselt-"Dincer correlations will be beneficial to scientists and industries concerned with heating and cooling applications.

“…A number of studies have been made in the past to relate the heat and mass transfer analysis during the cooling of food products (Ansari and Afaq, 1986;Ansari et al, 1984;Baird and Gaffney, 1976;Guemes et al, 1988; Hayakawa and Succar, 1982;and Sastry et al, 1985). Various methods developed for calculating heat and mass transfer in fruit and vegetables have been reviewed and discussed in detail (Gaffney et al, 1985).…”

Section: Introductionmentioning

confidence: 99%

An exact heat transfer analysis of spherical products subjected to forced-air cooling

Dinçer¹

1993

The thermal analysis of forced‐air cooling processes being of primary concern, an experimental and analytical study program was undertaken to investigate the heat transfer during the cooling of figs as spherical food products. The process conditions were analysed according to a mathematical model to gain a better understanding of the product's behaviour. The heat transfer between the product and air was influenced by conduction inside the product, convection outside the product, radiation, respiratory heat rate (internal heat generation), and moisture evaporation at the surface of the product. These situations were considered as three cases, such as h = hc, h = hc + hc, and h = hc, + hr + he. The four various air velocities of 1.1, 1.5, 1.75, and 2.5 m/s were applied in the experimental study. The results obtained by the mathematical model in the estimation of the heat transfer rates from the products were compared with the experimental data, and the best agreement was found for the third case (h = hc + hr + he). The fastest cooling was accomplished with the highest airflow velocity.