Numerical evaluation for cooling performance of a composite measure on expressway embankment with shady and sunny slopes in permafrost regions

Ma, Qinguo; Luo, Xiaoxiao; Jian-qiang, Gao; Sun, Weiyu; Lan, Tianli

doi:10.1016/j.energy.2022.123194

Cited by 19 publications

(6 citation statements)

References 35 publications

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“…We consider the error function 𝐸(𝑦) = 𝑔(𝑦) − 𝐼 𝑔(𝑦) , where 𝑔(𝑦) is the exact solution and 𝐼 𝑔(𝑦) is the approximate solution of a given problem obtained from the pseudospectral Chebyshev method. Then, from (35), we have…”

Section: Error Analysis For New Base Functionsmentioning

confidence: 99%

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Novel Numerical Investigations of Some Problems Based on the Darcy–Forchheimer Model and Heat Transfer

Akyildiz,

Alshammari,

Tunç

2024

Mathematics

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In this study, we introduced a new type of basis function and subsequently a Chebyshev delta shaped collocation method (CDSC). We then use this method to numerically investigate both the natural convective flow and heat transfer of nanofluids in a vertical rectangular duct on the basis of a Darcy–Brinkman–Forchheimer model and the electroosmosis-modulated Darcy–Forchheimer flow of Casson nanofluid over stretching sheets with Newtonian heating problems. The approximate solution is represented in terms of Chebyshev delta shaped basis functions. Novel error estimates for interpolating polynomials are derived. Computational experiments were carried out to corroborate the theoretical results and to compare the present method with the existing Chebyshev pseudospectral method. To demonstrate our proposed approach, we also compared the numerical solutions with analytic solutions of the Poisson equation. Computer simulations show that the proposed method is computationally cheap, fast, and spectrally accurate and more importantly the obtained approximate solution can easily be used by researchers in this field.

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Section: Error Analysis For New Base Functionsmentioning

confidence: 99%

“…But more recently, other methods have also been used in heating problems; for example, Athith, T. S., et al in [32] used a genetic algorithm and an artificial neural network in a heat exchanger with a partially filled different high-porosity metal foam problem. For other studies, we refer to the works [33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Novel Numerical Investigations of Some Problems Based on the Darcy–Forchheimer Model and Heat Transfer

Akyildiz,

Alshammari,

Tunç

2024

Mathematics

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“…During rainfall, evaporation and freezing-thawing process, the water within unsaturated soil migrates in the form of liquid water and vaporous water (Philip and De Vries, 1957;Saito et al, 2006). The convective effect of water influences the heat transfer in the unsaturated soil (Ma et al, 2022a;Ma et al, 2022b).…”

Section: Effect Of Sand Layer On Heat Convectionmentioning

confidence: 99%

The hydrothermal process of aeolian sand and its thermal effect on permafrost in Qinghai-Tibetan Plateau considering rainfall and evaporation under climate warming

Lan

Xia

et al. 2022

Front. Environ. Sci.

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As the heat exchange interface between atmosphere and permafrost, land cover regulates the influence of climate warming on permafrost. With the development of desertification on the Qinghai-Tibetan Plateau (QTP), aeolian sand has emerged as a significant environmental factor influencing the hydrothermal process of permafrost. To reveal the hydro-thermal process within aeolian sand layer and the thermal effect of sand layer on permafrost in the QTP, a coupled hydro-thermo-vapor model considering rainfall and evaporation was established, and the long-term hydrothermal variation of stratum covered by aeolian sand were analyzed. The results show that: 1) Aeolian sand layer is conducive to alleviating permafrost degradation. The alleviation effect is related to the thickness of sand layer. 2) Water redistribution in sand layer and water accumulation in stratum are connected to thickness of sand layer. For the thin sand layer, the water content is low and remains unchanged in different years. The thick sand layer, acting as a permeability diode, makes the degree of water accumulation in sand layer considerable and the water storage of the stratum increase continuously. 3) When the sand layer becomes thicker, the increment of the equivalent thermal conductivity in cold season is larger than that in warm season, which will lead to the decrease of annual conductive heat. 4) In thin sand layer, heat convection and heat conduction are relatively small in the early stage, and heat conduction is the primary mode in the long term. In thick sand layer, heat transfer is dominated by heat convection and heat conduction in the early stage, but it is primarily reliant on heat convection in the long term.

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“…Climate warming has led to the warming and thawing of permafrost at a global scale [1,2]. To alleviate the road settlement caused by permafrost degradation, a PRL, which has excellent and stable heat transfer performance, is widely used to maintain the thermal stability of road embankments in cold regions, such as along the Qinghai-Tibet Railway (QTR) in China, Baikal-Amur Railway in Russia, Inuvik-Tuktoyaktuk and Yukon Highway in northern Canada, and Taylor Highway in Alaska, USA [3][4][5][6][7]. However, climate change and frequent human activities have led to serious degradation and desertification of the grassland on the Qinghai-Tibet Plateau (QTP) [8].…”

Section: Introductionmentioning

confidence: 99%

“…Our study aims to: (1) understand the heat transfer laws of a PRL in aeolian sand environments; (2) find out the necessary conditions under which a PRL can maintain subgrade stability under the dual effects of climate warming and aeolian sand; (3) provide a scientific basis for the evaluation of the long-term stability of a PRL applied to frozen-soil engineering in the aeolian sand environment of the QTP. The PRL structure has excellent air convection and "thermal semiconductor" characteristics and has become the mainstream technology for maintaining the thermal stability of embankments in the permafrost zone of the QTP [3,7,11]. In recent years, the heat transfer mechanism of PRLs has undergone comprehensive exploration using diverse technical methods, including field monitoring, laboratory model tests, and numerical simulations [12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Heat Transfer of Porous Rock Layers in Cold Sandy Regions

Qiu,

Huang,

Han

et al. 2023

Atmosphere

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The heat transfer characteristics of porous rock layers (PRLs) have significant seasonal differences. This feature has been used to protect the permafrost subgrade under highways and railways from degeneration. However, in cold sandy environments, the transformation law of heat transfer characteristics of PRLs on account of climate warming and aeolian sand filling needs to be solved. This work developed a coupled heat transfer model for the soil–PRL system aimed at analyzing the convective heat transfer process and mechanism of a closed PRL. Furthermore, the impact of climate warming and sand filling on the cooling performance of the PRL under different mean annual air temperatures (MAATs) of −3.5, −4.5, and −5.5 °C was quantified. The numerical results indicated that the natural convection of the closed PRL occurred only in winter, and the effective convective height of the rock layer decreased with the sand-filling thickness. As the thickness of sand filling increased, the critical temperature difference for the occurrence of natural convection increased, accompanied by decreases in the Rayleigh number, the duration, and intensity of natural convection. When the sand-filling thickness exceeded 80 cm, natural convection would not occur in the PRL. Under a warming scenario of 0.052 °C·a−1, the cooling performance of the PRL could offset the adverse impact of climate warming and raise the permafrost table in the first 20 years. Moreover, the closed PRL can be more effective in permafrost regions with colder MAATs. For cold sandy permafrost zones, sand-control measures should be taken to maintain the long-term cooling performance of the PRL. This study is of great significance in guiding porous rock embankment design and road maintenance along the Qinghai–Tibetan Railway.

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Numerical evaluation for cooling performance of a composite measure on expressway embankment with shady and sunny slopes in permafrost regions

Cited by 19 publications

References 35 publications

Novel Numerical Investigations of Some Problems Based on the Darcy–Forchheimer Model and Heat Transfer

Novel Numerical Investigations of Some Problems Based on the Darcy–Forchheimer Model and Heat Transfer

The hydrothermal process of aeolian sand and its thermal effect on permafrost in Qinghai-Tibetan Plateau considering rainfall and evaporation under climate warming

Numerical Simulation of Heat Transfer of Porous Rock Layers in Cold Sandy Regions

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