Query:
学者姓名:王秋旺
Refining:
Year
Type
Indexed by
Source
Complex
Co-Author
Language
Clean All
Abstract :
Lee model is commonly accepted for modelling the mass transfer processes subject to both evaporation or condensation. However, the mass loss or mass excess always exist due to the mismatch of condensation and evaporation coefficients. Rare study focused on the proper ratio of them in closed systems. In present study, a dynamic correction model (named mass-conservation model) against to the condensation time relaxation coef-ficient is proposed, which can adjust the condensation coefficient in each time step considering the mass con-servation between the initial state and the current state. Three typical closed structures are introduced for model validation in which severe mass loss and temperature prediction deviation are recognized. Result shows that the mass variation calculated by present dynamic correction model is less than 0.5% while the maximum mass loss with other models could reach 48.31%. Meanwhile, the prediction error of the three Cases calculated with the present model is the smallest, with the maximum decrement of 29.73% compared with other models. It is also realized that the insufficient heat release and the mass non-conservation are the key factor resulting in the temperature prediction deviation, which is well solved by present correction model on condensation time relaxation coefficient.
Keyword :
Condensation coefficient Lee model Mass conservation Volume of fluid
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Tan, Zhoutuo , Cao, Zehan , Chu, Wenxiao et al. Dynamic correction on condensation time relaxation coefficient of Lee model based on mass conservation mechanism [J]. | INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER , 2023 , 142 . |
MLA | Tan, Zhoutuo et al. "Dynamic correction on condensation time relaxation coefficient of Lee model based on mass conservation mechanism" . | INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER 142 (2023) . |
APA | Tan, Zhoutuo , Cao, Zehan , Chu, Wenxiao , Wang, Qiuwang . Dynamic correction on condensation time relaxation coefficient of Lee model based on mass conservation mechanism . | INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER , 2023 , 142 . |
Export to | NoteExpress RIS BibTex |
Abstract :
In applications of solar energy, thermal ratcheting is a crucial topic connected to the periodic performance of dual-phase thermocline storage tank. In order to investigate this phenomenon, a detailed simulation of a ther-mocline reservoir that includes both the hybrid tank wall and the varied filling zone is necessary. The thermo-mechanical characteristic of the cascaded layers storage tank for parabolic trough power plants is examined in the current work using one parametric study (dimensionless temperature difference) to determine the impact of changing the melting temperature of the phase change material (PCMs) layers. Experimental work from earlier studies is utilized to validate the numerical outcomes currently being presented. The results showed that structures-VIII and XIV have acceptable thermal performance, but ineffective mechanical performance since the normalized stress values were greater than one. The structure-XIII has the best overall efficiency of 79.58%, followed by structures-II, III, and XI, with performance levels of 70.82%, 67.83%, and 66.85%, respectively. The lowest overall efficiency attains by structure-XII, which equals 22.21%. The energy retrieved, overall efficiency, capacity ratio, and utilization ratio for the best scenario "structures-XIII '' are 188.2 MWh, 79.58%, 44.34%, and 40.5%, respectively, based on the charging/discharging duration.
Keyword :
Cascaded layers tank PCM melting temperature Plastic deformation Solar power plant Thermal ratcheting
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Elfeky, Karem Elsayed , Mohammed, Abubakar Gambo , Ahmed, Naveed et al. Thermo-mechanical investigation of the multi-layer thermocline tank for parabolic trough power plants [J]. | ENERGY , 2023 , 268 . |
MLA | Elfeky, Karem Elsayed et al. "Thermo-mechanical investigation of the multi-layer thermocline tank for parabolic trough power plants" . | ENERGY 268 (2023) . |
APA | Elfeky, Karem Elsayed , Mohammed, Abubakar Gambo , Ahmed, Naveed , Wang, Qiuwang . Thermo-mechanical investigation of the multi-layer thermocline tank for parabolic trough power plants . | ENERGY , 2023 , 268 . |
Export to | NoteExpress RIS BibTex |
Abstract :
This article presents a fully three-dimensional numerical study on the process of melt pool evolution. To overcome the simplifications used in many existing studies, an enthalpy method is developed for the phase change, and an accurate interface capturing method, i.e., the coupled volume-of-fluid and level set (VOSET) method, is employed to track the moving gas-liquid interface. Meanwhile, corresponding experimental studies are carried out for validation. The obtained numerical results show the formed interface morphology during the process of melt pool with its typical sizes and are quantitatively consistent with those data measured in experiments. Based on the numerical results, the thermodynamic phenomena, induced by the interaction between heat and momentum exchange, occurring in the formation of melt pool are presented and discussed. Mechanisms of the melt pool evolution revealed in the present study provide a useful guidance for better controlling the process of additive manufacturing.
Keyword :
additive manufacturing evolution phenomena free surface heat transfer in manufacturing melting and solidification melt pool VOSET method
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Bian, Qingfei , Tian, Ke , Ling, Kong et al. Transport Phenomena and Evolution Mechanism of the Melt Pool During a Laser-Based Metal Melting Process [J]. | JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS , 2022 , 14 (12) . |
MLA | Bian, Qingfei et al. "Transport Phenomena and Evolution Mechanism of the Melt Pool During a Laser-Based Metal Melting Process" . | JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS 14 . 12 (2022) . |
APA | Bian, Qingfei , Tian, Ke , Ling, Kong , Chen, Yitung , Zeng, Min , Wang, Qiuwang . Transport Phenomena and Evolution Mechanism of the Melt Pool During a Laser-Based Metal Melting Process . | JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS , 2022 , 14 (12) . |
Export to | NoteExpress RIS BibTex |
Abstract :
The purpose of the present study is to simulate the continuous bend erosion process in different directions, using the dense discrete particle model (DDPM). The influence of the length of the straight pipe in the middle of the continuous bend is investigated. The Rosin-Rammler method is introduced to define the diameter distribution of erosion particles, which is theoretically closer to the actual engineering erosion situation. The numerical model is based on the Euler-Lagrange method, in which the continuous phase and the particle phase are established on a fixed Euler grid. The Lagrange model is used to track the particles, and the interaction between particles is simulated by particle flow mechanics theory. The velocity field distribution, pressure variation, and turbulent kinetic energy of gas-solid two-phase flow, composed of natural gas and gravel in the pipeline, are studied. The simulation results, using the one-way coupled DPM and the four-way coupled DDPM, are compared and analyzed. The results show that the DDPM has good accuracy in predicting the distribution of the continuous bend erosion processes in different directions. The erosion rates of particles with an average distribution size of 50 mu m are significantly increased (8.32 times), compared with that of 10 mu m, at the same gas transmission rate. It is also indicated that it is important to consider the impact between particles and the coupling between fluid and particles in the erosion simulation of the continuous elbow when using the CFD method.
Keyword :
DDPM-KTGF erosion modelling erosion reduction gas-solid two-phase flow Rosin-Rammler distribution
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Li, Bingcheng , Zeng, Min , Wang, Qiuwang . Numerical Simulation of Erosion Wear for Continuous Elbows in Different Directions [J]. | ENERGIES , 2022 , 15 (5) . |
MLA | Li, Bingcheng et al. "Numerical Simulation of Erosion Wear for Continuous Elbows in Different Directions" . | ENERGIES 15 . 5 (2022) . |
APA | Li, Bingcheng , Zeng, Min , Wang, Qiuwang . Numerical Simulation of Erosion Wear for Continuous Elbows in Different Directions . | ENERGIES , 2022 , 15 (5) . |
Export to | NoteExpress RIS BibTex |
Abstract :
Determining and modelling the effective thermal conductivity of nanofluids is always a concern of investigators. The effect of nanoparticles' shape on the effective thermal conductivity of nanofluids has not been accurately correlated with other influencing factors such as temperature and nanoparticle concentration. The main purpose of this study is to reveal the effects of influencing factors on the effective thermal conductivity of nanofluids by experimental investigation and artificial intelligence (AI). We prepared the TiO2/water nanofluids with four shapes of TiO2 nanoparticles (spherical, ellipsoidal, clubbed, and sheet) and measured the effective thermal conductivities of the samples with nanoparticles concentrations from 0.5 to 4.0 vol% as a function of temperature from 20 to 60 degrees C. Besides, 389 experimental datasets collected from literature and 80 datasets from our experiment were used to determine the optimum structure of AI-based models. Temperature, concentrations, shape factor, and thermal conductivity of nanoparticles were selected as independent variables, and the relative thermal conductivity of nanofluids was selected as the dependent variable. Six AI-based models were examined, including four artificial neural networks of multi-layer perceptron, cascade feedforward, radial basis function, and generalized regression neural network, adaptive neuro-fuzzy inference systems, and least-squares support vector machines, and the estimating performances were compared. The experimental results showed that increasing temperature and nanoparticles concentrations led to a remarkable improvement in the relative thermal conductivity of nanofluids, attributed to the intensified Brownian motion of nanoparticles with the high temperature and the effective collision of nanoparticles with the high concentrations. Besides, nanoparticles with a large aspect ratio provided the fast pathway with seldom crossing an interparticle boundary or junction point for effective heat transfer in the nanofluids, resulting in higher relative thermal conductivity of nanofluids. Statistical analyses confirmed that the cascade feed-forward neural network with ten hidden neurons and the Levenberg-Marquardt training algorithms was the optimized AI-based model for estimating the relative thermal conductivity of nanofluids. This model estimated allover experimental data by MSE = 0.0039, RMSE = 0.0622, AARD% = 2.66%, and R-2 = 0.9908. (C) 2021 Elsevier B.V. All rights reserved.
Keyword :
Artificial intelligence Experiment Nanofluids Nanoparticles shapes Thermal conductivity
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Cui, Wei , Cao, Zehan , Li, Xinyi et al. Experimental investigation and artificial intelligent estimation of thermal conductivity of nanofluids with different nanoparticles shapes [J]. | POWDER TECHNOLOGY , 2022 , 398 . |
MLA | Cui, Wei et al. "Experimental investigation and artificial intelligent estimation of thermal conductivity of nanofluids with different nanoparticles shapes" . | POWDER TECHNOLOGY 398 (2022) . |
APA | Cui, Wei , Cao, Zehan , Li, Xinyi , Lu, Lin , Ma, Ting , Wang, Qiuwang . Experimental investigation and artificial intelligent estimation of thermal conductivity of nanofluids with different nanoparticles shapes . | POWDER TECHNOLOGY , 2022 , 398 . |
Export to | NoteExpress RIS BibTex |
Abstract :
Gravity-driven granular flow has been the heat transfer mediums in moving bed heat exchangers, which play vital roles in industrial heat saving and solar energy utilization. However, the heat transfer mechanism of granular flow is still worth of investigating around the tube bank. In this work, the aligned tubes were arranged in the moving bed, and the heat transfer of metallurgical slag was experimentally tested. It was found that, the heat transfer coefficients are significantly sensitive to the flow rate in the slow granular flow. The smooth flow with particle mixing can improve the heat transfer, while the local particle lagging will worsen the heat transfer around aligned tubes. To predict heat transfer coefficients of granular flow, the contact thermal resistance and the penetration thermal resistance are built with empirical factors (chi, a and 1). In the near-wall region, x rep-resents the sensitivity of the contact thermal resistance to particle sizes. Meanwhile, the contact time can be modified by a and 1 for the penetration thermal resistance in the funnel flow structure. The values of a and 1 are affected by the granular flow pattern, which tend to decrease in the smooth flow with strong particle mixing. Verified with the present experimental results and the previous literature data, the thermal resistance model has great potentials to explain the heat transfer around the aligned tube bank.
Keyword :
Contact time Granular flow Heat transfer Moving bed heat exchanger Thermal resistance model
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Guo, Zhigang , Tian, Xing , Wu, Zhihong et al. Heat transfer of granular flow around aligned tube bank in moving bed: Experimental study and theoretical prediction by thermal resistance model [J]. | ENERGY CONVERSION AND MANAGEMENT , 2022 , 257 . |
MLA | Guo, Zhigang et al. "Heat transfer of granular flow around aligned tube bank in moving bed: Experimental study and theoretical prediction by thermal resistance model" . | ENERGY CONVERSION AND MANAGEMENT 257 (2022) . |
APA | Guo, Zhigang , Tian, Xing , Wu, Zhihong , Yang, Jian , Wang, Qiuwang . Heat transfer of granular flow around aligned tube bank in moving bed: Experimental study and theoretical prediction by thermal resistance model . | ENERGY CONVERSION AND MANAGEMENT , 2022 , 257 . |
Export to | NoteExpress RIS BibTex |
Abstract :
In this paper, the flow condensation heat transfer characteristics of R32 in a horizontally oriented tube with a horizontal U-bend (HUB tube) and a horizontally oriented tube with a vertical U-bend (VUB tube) were numerically investigated. The volume of fluid (VOF) multiphase model with the mass transfer assumption by Lee is adopted to simulate the flow condensation behavior of R32, which are validated by well-known empirical correlations. The influence of structural parameters, mass flux and vapor quality on the heat transfer coefficient (HTC) and liquid film distribution is investigated. Meanwhile, the local liquid film thickness (LLFT) and local heat transfer coefficient (LHTC) are also depicted. The phase transition at the U-bend section is captured. Results show that the U-bend has remarkable disturbance on the flow pattern and LHTC due to the effect of centrifugal force where the LLFT is changed, inducing strong secondary flow. The LHTC is increased by a maximum of 8.47% and 11.86% in VUB tube and HUB tube, respectively, when compared to the case in a horizontally straight oriented tube at the same operating conditions.
Keyword :
film thickness heat transfer coefficient R32 flow condensation VOF model
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Cao, Zehan , Zhang, Hao , Mei, Haohan et al. Numerical Study on R32 Flow Condensation in Horizontally Oriented Tubes with U-Bends [J]. | ENERGIES , 2022 , 15 (13) . |
MLA | Cao, Zehan et al. "Numerical Study on R32 Flow Condensation in Horizontally Oriented Tubes with U-Bends" . | ENERGIES 15 . 13 (2022) . |
APA | Cao, Zehan , Zhang, Hao , Mei, Haohan , Yan, Gang , Chu, Wenxiao , Wang, Qiuwang . Numerical Study on R32 Flow Condensation in Horizontally Oriented Tubes with U-Bends . | ENERGIES , 2022 , 15 (13) . |
Export to | NoteExpress RIS BibTex |
Abstract :
Phase change materials (PCMs) have been considered suitable energy materials to address the mismatch between energy demand and supply to improve the utilization efficiency of the latent heat thermal energy storage (LHTES) system. However, the relatively low thermal conductivity of PCMs leads to an undesirable thermal response rate of the LHTES system. Among the common methods to improve the heat transfer performance of PCMs, the employment of metal foam (MF) has attracted growing attention as an effective strategy. Plenty of studies have investigated thoroughly the vital parameters of MF impacting the phase change process, while a corresponding discussion of the situations and limitations of the known technologies is still lacking. In this re-view, a total of 476 literature derived since 2000 are visualized based on scientometric analysis to exhibit the attractive spotlights and new trends. The impact factors on the heat transfer performance of PCMs embedded with MF (PCMs/MF) are presented in-depth. Besides, the developments of hybrid heat transfer enhancement techniques based on the MF are overviewed comprehensively. Combined with the thermal characteristics of typical applications, systematic information on PCMs/MF in these applications is summarized, and the suitability of these technologies is discussed. Finally, ongoing challenges of PCMs/MF are identified, and developmental tendencies and opportunities for further research work to address them are discussed. This review provides helpful information to facilitate the development of innovative and feasible PCMs/MF in the LHTES system and encourage and attract researchers and scholars to get some advancement in their future work.
Keyword :
Heat transfer enhancement Metal foam Phase change materials Thermal energy storage
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Cui, Wei , Si, Tianyu , Li, Xiangxuan et al. Heat transfer enhancement of phase change materials embedded with metal foam for thermal energy storage: A review [J]. | RENEWABLE & SUSTAINABLE ENERGY REVIEWS , 2022 , 169 . |
MLA | Cui, Wei et al. "Heat transfer enhancement of phase change materials embedded with metal foam for thermal energy storage: A review" . | RENEWABLE & SUSTAINABLE ENERGY REVIEWS 169 (2022) . |
APA | Cui, Wei , Si, Tianyu , Li, Xiangxuan , Li, Xinyi , Lu, Lin , Ma, Ting et al. Heat transfer enhancement of phase change materials embedded with metal foam for thermal energy storage: A review . | RENEWABLE & SUSTAINABLE ENERGY REVIEWS , 2022 , 169 . |
Export to | NoteExpress RIS BibTex |
Abstract :
由于成本低,运行稳定,重力驱动移动床在高温固体散料余热回收领域应用潜力较大.然而,相关强化传热技术目前仍待完善.本文基于离散单元法,对颗粒流外掠翅片单元的流动换热特性进行了数值研究.研究表明:通过翅片增加换热面,可以显著提高传热量,但不同翅片单元外颗粒流传热特性不同.颗粒流与不同表面的换热,由颗粒更新、颗粒接触、颗粒竞争掺混以及表面面积共同决定.总体来说,在迎流区,倾斜平表面能扩大面积并确保颗粒更新,更有利于换热增强.而对于背流区,竞争掺混与颗粒接触的影响更大,采用圆弧表面更有优势.
Keyword :
翅片单元 颗粒流 离散单元法 强化传热 重力驱动移动床
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | 郭志罡 , 杨剑 , 田兴 et al. 不同翅片单元外颗粒流换热特性的数值研究 [J]. | 工程热物理学报 , 2021 , 42 (4) : 1015-1020 . |
MLA | 郭志罡 et al. "不同翅片单元外颗粒流换热特性的数值研究" . | 工程热物理学报 42 . 4 (2021) : 1015-1020 . |
APA | 郭志罡 , 杨剑 , 田兴 , 谈周妥 , 王秋旺 . 不同翅片单元外颗粒流换热特性的数值研究 . | 工程热物理学报 , 2021 , 42 (4) , 1015-1020 . |
Export to | NoteExpress RIS BibTex |
Abstract :
Due to the low cost and the stable operation condition, the gravity-driven moving bed has great application potentials in the waste heat recovery of hot solid granule. However, the relevant technology of heat transfer enhancement is still in advancing. In this work, discrete element method (DEM) was applied to investigate the heat transfer of granular flow around different fin elements. It was found that, the fin can increase the heat transfer area so that the heat transfer is significantly improved, while the detailed characteristics of granular flow will differ with the fin element. The heat transfer between the granular flow and different surfaces, is integrated by the particle update, the particle contact, the competitive particle mixing as well as the surface area. In general, in the upstream side, the inclined plane can increase the area with the relatively smooth flow. Therefore, it is more beneficial to improve the heat transfer. By contrast, the arc surface has more advantages in the downstream, because the particle contact and the competitive particle mixing will account for more roles here. © 2021, Science Press. All right reserved.
Keyword :
Confined flow Finite difference method Fins (heat exchange) Granular materials Heat transfer Mixing Waste heat Waste heat utilization
Cite:
Copy from the list or Export to your reference management。
GB/T 7714 | Guo, Zhi-Gang , Yang, Jian , Tian, Xing et al. Numerical Study on Heat Transfer Characteristic of Granular Flow Around Different Fin Elements [J]. | Journal of Engineering Thermophysics , 2021 , 42 (4) : 1015-1020 . |
MLA | Guo, Zhi-Gang et al. "Numerical Study on Heat Transfer Characteristic of Granular Flow Around Different Fin Elements" . | Journal of Engineering Thermophysics 42 . 4 (2021) : 1015-1020 . |
APA | Guo, Zhi-Gang , Yang, Jian , Tian, Xing , Tan, Zhou-Tuo , Wang, Qiu-Wang . Numerical Study on Heat Transfer Characteristic of Granular Flow Around Different Fin Elements . | Journal of Engineering Thermophysics , 2021 , 42 (4) , 1015-1020 . |
Export to | NoteExpress RIS BibTex |
Export
Results: |
Selected to |
Format: |