Research Progress on Convective Heat Transfer Characteristics of Supercritical Fluids in Curved Tube

Liu, Xinxin; Li, Shuoshuo; Liu, Liang; He, Chao; Sun, Zhuang; Özdemir, Faruk; Aziz, Muhammad; Kuo, Po-Chih

doi:10.3390/en15228358

Cited by 7 publications

(4 citation statements)

References 115 publications

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“…Using the same material, various combinations of working medium, such as AA/Air and AA/He, have different EHTC values. Additionally, the temperature amplitude ΔT in Equation (36) appears on the denominator, so its variations are the opposite of Equation (27). The frequency and the thermal diffusion coefficient of the fluid both influence the EHTC of the gas, as Figure 19 suggests.…”

Section: The Ehtc Under Oscillationmentioning

confidence: 98%

“…When the thermal diffusi coefficient is large, the heat conducts more quickly and the homogeneity of the temper ture distribution is be er; therefore, the change rate of the curve is relatively small. According to Equation (27), at the fluid-solid coupling wall, the temperature amp tude changes with the frequency when different combinations of materials and worki medium are present. Figures 13a,b illustrate how the wall temperature amplitude vari when the material remains unchanged and the working medium is changed.…”

Section: Heat Transfer Characteristics Of the Fluid-solid Coupling Su...mentioning

confidence: 99%

“…According to Equation (30), when r = R 1 , the heat of the fluid is the same as that of the solid on the surface. Equation (31) expresses the fluid heat Q rw (R 1 ) when r = R 1 , where the heat transfer area S is related to diameter R 1 and length L; τ denotes the heat transfer time; and ∆T is the temperature amplitude, as shown in Equation (27). Thus, the EHTC K is:…”

Section: The Ehtc Under Oscillationmentioning

confidence: 99%

“…The aim is to solve the temperature, velocity, and heat distribution and to accurately satisfy the thermal conduction differential equation and the conditions of the definite solution at all internal points. In the past, researchers paid more attention to the study of the single media of a fluid or solid, while heat transfer of the fluid-solid coupling surface was largely ignored [25][26][27]. Therefore, it is necessary to further study the oscillating flow within the low-temperature differences with the low-flow resistance of a normal hexagonal bundle regenerator.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Fluid-Solid Coupling Radial Heat Transfer Characteristics in a Normal Hexagonal Bundle Regenerator under Oscillating Flow

Wang,

Zhang,

et al. 2023

Energies

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The main purpose of this paper is to analyze the heat transfer mechanism of a new type of regenerator with a low temperature difference and low current resistance under oscillatory flow at room temperature. Taking the single tube of the regenerator as the research object, the exact analytical solution of the radial heat transfer characteristics of the regenerator is obtained by studying its analytical model. The factors affecting the heat transfer characteristics are analyzed, and then the regenerator is optimized to improve the performance and efficiency of the regenerator system. In this study, we systematically analyzed the radial heat transfer characteristics of a regenerator under isochoric process conditions. A closed-system physical model of the incompressible isochoric process under oscillating flow was established. Then, the radial analytical solutions of pressure fluctuation, fluid velocity, fluid-solid temperature, and heat were derived in the complex number field. Furthermore, the fluid velocity, fluid-solid coupling wall temperature, heat, and equivalent heat transfer coefficient were assessed. Furthermore, the influences of frequency, inner diameter R1 of the regenerator, and different working medium and materials on the above parameters were discussed. It was found that the analysis and evaluation of fluid velocity, fluid-structure coupling wall temperature, heat, and equivalent heat transfer coefficient are helpful in understanding the dynamic characteristics of radial heat transfer in a regenerator system. Through the study of radial heat transfer under oscillating flow, it was found that the working medium, frequency, inner diameter of the regenerator, and material quality of the regenerator are helpful for the design optimization of the regenerator. Furthermore, our investigations established that the variation law of wall fluid-solid coupling temperature amplitude could be divided into three parts: the unidirectional flow part; the low-frequency part, where the temperature amplitude falls rapidly with increasing frequency; and the high-frequency part, where the temperature amplitude increases with the frequency. In addition, the variation of radial heat transfer of the fluid-solid coupling surface is similar to the changes in the temperature amplitude. We also discovered that the equivalent heat transfer coefficient of the fluid-solid surface is related to thermal conductivity of the material. Specifically, larger thermal conductivity values result in greater equivalent heat transfer coefficients. Based on the research into the radial heat transfer characteristics, the new regenerator has great application potential in the Stirling air conditioning system at room temperature.

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Section: The Ehtc Under Oscillationmentioning

confidence: 98%

Section: Heat Transfer Characteristics Of the Fluid-solid Coupling Su...mentioning

confidence: 99%

Section: The Ehtc Under Oscillationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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