A new partitioned 1D LTNE continuum model for the simulation of 3D-shaped honeycomb absorbers

Broeske, Robin Tim; Schwarzbözl, Peter; Hoffschmidt, Bernhard

doi:10.1016/j.solener.2022.02.024

Cited by 10 publications

(5 citation statements)

References 25 publications

(31 reference statements)

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“…The proposed formula was validated using a numerical method on the DLR computer model. The computational model was built in the OpenFOAM Version 6 open-source software environment and included 4164 Nusselt number calculations for various configurations of the StepRec2 absorber, each with different input parameters [ 21 ]. Below are validation graphs ( Figure 5 , Figure 6 , Figure 7 , Figure 8 and Figure 9 ) comparing calculations using the proposed formula with those using the standard engineering method outlined in HeatAtlas [ 16 ].…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, in Figure 1 , the range Re ∈ [5;150] is chosen. The data obtained using a numerical model for high-temperature solar receivers [ 21 ] (based on the numerical LTNE method) are listed as the “numerical DLR method”. “Numerical DLR method front” is a Nusselt calculation for the flow perpendicular to the porous medium (used for the surface of a porous absorber).…”

Section: Methods Of Contemporary Models Of Convective Heat Transfer C...mentioning

confidence: 99%

“…An attempt is made to calculate the Nusselt numbers in the channel of a porous absorber by the classical method of determining the coefficients of dependence of the Nusselt number on the Reynolds number using data from the numerical method [ 21 ]. The channel of the porous absorber StepRec2 is shown in Figure 2 .…”

Section: Methods Of Contemporary Models Of Convective Heat Transfer C...mentioning

confidence: 99%

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Analytical Determination of Nusselt Numbers for Convective Heat Transfer Coefficients in Channel Macroporous Absorbers

Cheilytko,

Schwarzbözl,

Broeske

2024

Materials

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This article introduces a novel analytical equation for computing the Nusselt number within the macroporous structures of channel absorbers utilized in high-temperature solar receivers. The equation incorporates heat and mass transfer processes occurring within boundary layers as fluid flows through complex-shaped macroporous absorber channels. The importance of accounting for the length of the thermodynamic boundary layer within channel-type macroporous media when calculating heat transfer coefficients using the Nusselt equation is demonstrated. By incorporating proposed indicators of porosity and flow characteristics, this method significantly enhances the accuracy of heat transfer coefficient calculations for such media. Discrepancies observed in existing calculation relationships and experiments are attributed to the omission of certain proposed values in the Nusselt number for macroporous media. To address this, empirical coefficients for the Nusselt number are derived using statistical methods. The resulting semi-empirical equation is applied to macroporous absorbers in solar receivers. The findings enable more accurate predictions of future absorber characteristics, enhancing their efficiency. The derived equation is successfully validated against numerical data across various geometric structures of absorbers in concentrated solar power plants.

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Section: Resultsmentioning

confidence: 99%

Section: Methods Of Contemporary Models Of Convective Heat Transfer C...mentioning

confidence: 99%

Section: Methods Of Contemporary Models Of Convective Heat Transfer C...mentioning

confidence: 99%

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Analytical Determination of Nusselt Numbers for Convective Heat Transfer Coefficients in Channel Macroporous Absorbers

Cheilytko,

Schwarzbözl,

Broeske

2024

Materials

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“…StepRec2 absorber with different input parameters [21]. Below are the validation graphs for five sections for different section lengths of the StepRec2 model with a comparison of the calculation with standard engineering method in accordance with HeatAtlas [16] (green point in Figure 5-Figure 9).…”

Section: Resultsmentioning

confidence: 99%

“…Reynolds for engineering problems of determining heat transfer in absorbers of high-temperature solar receivers using data from the numerical method [21]. The channel of the porous absorber…”

Section: 𝑋 = 𝐿 𝑑 𝑒 𝑅𝑒𝑃𝑟mentioning

confidence: 99%

Analytical Determination of Nusselt Numbers for Convective Heat Transfer Coefficients in Macroporous Absorbers of High-Temperature Solar Receivers

Cheilytko,

Schwarzbözl,

Broeske

2023

Preprint

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The article presents a new analytical equation for calculating the Nu number in a macroporous structure of channel absorbers for high- temperature solar receivers. This equation is characterized by including the processes of heat and mass transfer in the boundary layers when the flow passes through a macroporous absorber channel of complex shape. The necessity of considering the length of the thermodynamic boundary layer in a macroporous medium of channel type, when calculating the heat transfer coefficient according to the Nusselt equation, is shown. Including the proposed indicators of porosity and flow characteristics in a macroporous channel significantly increases the accuracy of calculations of the heat transfer coefficient for macroporous channel media. The lack of consideration of certain of the proposed values in the Nusselt number for macroporous media explains the discrepancies in the existing calculation relationships and experiments. The empirical coefficients for the Nusselt number are proposed and obtained by the statistical method. The new semi-empirical equation obtained for macroporous channel media is applied to macroporous absorbers of solar receivers. The obtained results will help to predict the characteristics of future macroporous absorbers much more accurately than before to make them more efficient. The obtained equation for calculating the Nusselt number for channel-like macroporous absorbers has been successfully tested for the receiver of concentrated solar power plants with different geometric structure of the absorber.

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Micro-scaling numerical model coupled with experimental validation of the pressure drop for dense wire mesh

Sanchez-Señoran,

Reyes-Belmonte,

Farchado

et al. 2024

International Journal of Heat and Mass Transfer

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A new partitioned 1D LTNE continuum model for the simulation of 3D-shaped honeycomb absorbers

Cited by 10 publications

References 25 publications

Analytical Determination of Nusselt Numbers for Convective Heat Transfer Coefficients in Channel Macroporous Absorbers

Analytical Determination of Nusselt Numbers for Convective Heat Transfer Coefficients in Channel Macroporous Absorbers

Analytical Determination of Nusselt Numbers for Convective Heat Transfer Coefficients in Macroporous Absorbers of High-Temperature Solar Receivers

Micro-scaling numerical model coupled with experimental validation of the pressure drop for dense wire mesh

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