On the rate of cooling of aerated food grains

Thorpe, Graham

doi:10.1016/j.biosystemseng.2022.08.001

Cited by 7 publications

(5 citation statements)

References 22 publications

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“…Under a condition of constant pressure the specific enthalpy, h , can be expressed as h = h(w, T) and by employing the chain rule of partial differentiation, Eqs. 2.1 and 2.3 become and 3 The Velocities of Moisture and Temperature Waves Thorpe (2022) provides a detailed demonstration of the solution of Eqs. 2.4 and 2.5 by means of a classical application of the method of characteristics presented by Rhee et al (2013).…”

Section: Mathematical Backgroundmentioning

confidence: 99%

“…Conversely, (𝜕H∕𝜕h) 2 < 𝜎 corresponds to the temperature wave propagating with a relatively high velocity through beds of hygroscopic porous media, and this occurs along the more rapidly travelling temperature wave, PB. Along moisture and temperature waves Thorpe (2022) shows that Equation 3.3 has a simple form that provides insights into the behaviour of ventilated beds of hygroscopic porous media. However, it is necessary to evaluate ( w∕ T) j and ( W∕ T) j .…”

Section: Mathematical Backgroundmentioning

confidence: 99%

“…However, we shall observe that Toth's isotherm predicts the formation of a discontinuity in the moisture wave. Thorpe (2022) demonstrates that the thermodynamic states on either side of a discontinuity in a ventilated bed of hygroscopic porous media are governed by the following relationship…”

Section: Discontinuitiesmentioning

confidence: 99%

“…Chakraborty et al (2009) demonstrate how the sorption properties influence the apparent specific heat of silica gel (Type 125). When considering heat and mass transfer in stored food grains Thorpe (2022) noted that subsuming H W ∕ T into the specific heat of the solid phase is necessary when sorption data are incomplete, or internally inconsistent.…”

Section: Physical Propertiesmentioning

confidence: 99%

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Heat and Mass Transfer in Hygroscopic Porous Media: Consequences of Invoking Tóth’s Sorption Isotherm

Thorpe

2023

Transp Porous Med

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The thermal performance of ventilated beds of hygroscopic porous media depends strongly on the sorption properties of the solid phase. Furthermore, the published literature shows that the predicted performance of ventilated beds of hygroscopic porous media is extremely sensitive to the form and accuracy of the sorption isotherm. This is particularly apparent under idealized conditions when thermodynamic equilibrium is deemed to exist between the solid and fluid phases. When Tóth’s isotherm is invoked in an equilibrium model used to analyse the performance of a bed of initially warm and dry silica gel ventilated with cool, humid air, it is predicted that a shock wave develops downstream of air entering the bed. In contrast, it is shown that non-equilibrium solutions result in a transfer wave, the width of which decreases as the velocity of the interstitial air decreases. The Tóth isotherm gives rise to erroneous values of the integral heat of wetting of silica gel. Previously published studies of simultaneous heat and mass transfer in beds of hygroscopic materials refer to conceptual difficulties in interpreting the results, and some published mathematical analyses are somewhat terse. A secondary aim of this work is to assuage these difficulties by detailing the analyses in Supplementary Information.

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Section: Mathematical Backgroundmentioning

confidence: 99%

Section: Mathematical Backgroundmentioning

confidence: 99%

Section: Discontinuitiesmentioning

confidence: 99%

Section: Physical Propertiesmentioning

confidence: 99%

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Heat and Mass Transfer in Hygroscopic Porous Media: Consequences of Invoking Tóth’s Sorption Isotherm

Thorpe

2023

Transp Porous Med

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“…In a study conducted to understand and measure the factors determining the cooling rate of stored food grains, it was observed that the hygroscopic properties of food grains change the specific heats of grain and air [13].…”

Section: Introductionmentioning

confidence: 99%

Effect of Geometry Upon Cooling Characteristics of Wafer Block Coolers

Bitkin¹,

Tazegül²,

Okumuşer³

et al. 2023

adeletters

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The product formed after the cream is spread between the wafer sheets is called a wafer block. The wafer block can have a minimum of 3 layers (2 sheets, 1 cream) and a maximum of 9 layers (5 sheets, 4 creams). The temperature of the wafer block before entering the cooling tower is 30-35°C. After the cooling process is completed, it cannot be reduced to the outlet temperature (~16°C) and the temperature is not homogeneously distributed. Especially the middle regions are hot. In this paper, the homogeneous temperature distribution is aimed at by using the CFD method. CFD analysis of three predetermined designs was performed using Solidworks / Flow Simulation software. The first design is the one currently used. In the second design, a design improvement has been made to reduce the effect of vortices in dead zones. In the third design, a design improvement was made to positively affect the flow rate in the upper region where the evaporator and fan are located. In the second design, the temperature difference on the wafer block is reduced by 0.02°C compared to the current design. The third design decreases by 0.13°C compared to the second design.

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