Article
Thermodynamics
Obinna Uyanna, Hamidreza Najafi, Bhuvaneswari Rajendra
Summary: Effective design of thermal protection system (TPS) and health monitoring systems (HMS) for space vehicles relies on accurate flight data, surface heat flux estimation, and temperature dependent material properties. A solution approach based on Tikhonov regularization method is developed for real-time calculation of surface heat flux in a three-layer integrated thermal protection system (ITPS). Parametric study shows the solution's capability in evaluating surface heat flux with average RMS errors less than 5%. This proposed technique offers fast and accurate monitoring capabilities for space vehicles and industrial applications.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Multidisciplinary
Hui Wang, Tao Zhu, Xinxin Zhu, Kai Yang, Qiang Ge, Maogang Wang, Qingtao Yang
Summary: Compared with cold-wall heat flux measurement, hot-wall heat flux measurement provides more information on dynamic heat transfer and has become predominant in aerothermodynamic measurement field. A novel inverse estimation method using nonlinear artificial neural networks for hot-wall heat flux is proposed in this paper, which avoids certain difficulties in traditional methods and has been validated to work effectively.
Article
Engineering, Multidisciplinary
W. B. da Silva, J. C. S. Dutra, C. E. P. Kopperschimidt, D. Lesnic, R. G. Aykroyd
Summary: The paper successfully estimates the time-dependent HTC in two-dimensional transient inverse heat conduction problems by combining MFS and PF-SIR methods, confirming the synergy between the two approaches.
APPLIED MATHEMATICAL MODELLING
(2021)
Article
Thermodynamics
Zhi-Tian Niu, Hong Qi, Yu-Kun Ji, Shuang Wen, Ya-Tao Ren, Ming-Jian He
Summary: In this study, a novel method is proposed to introduce geometric analytical formulas into the multi-scale heat transfer problem of porous materials. The time-varying heat flux of different materials is reconstructed based on measurement information obtained from temperature sequence in a short time. The effects of photothermal properties, porosity, scattering albedo, and specularity parameter on the accuracy and stability of the reconstructed heat flux are investigated.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Rodrigo G. Dourado da Silva, Elisan S. Magalhaes, Luis Carlos M. Pires
Summary: This study presents a methodology to simulate heat transfer during the burning process of thermite in a wellbore. It estimates the heat flux using an inverse heat conduction problem, simplifying the physical model and reducing computational cost.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Environmental Sciences
Zhanat Karashbayeva, Julien Berger, Helcio R. B. Orlande, Bolatbek Rysbaiuly
Summary: In this study, the ground diffusivity was indirectly measured by solving an inverse problem. The conjugate gradient method with adjoint problem formulation was used to obtain stable and effective results, which were consistent with literature values.
Article
Thermodynamics
Obinna Uyanna, Hamidreza Najafi
Summary: A novel approach using Tikhonov regularization method and filter coefficients has been proposed, which can accurately estimate heat flux in a one-dimensional domain with moving boundary and temperature dependent material properties. The method is computationally efficient and offers real-time operation, making it suitable for applications such as ablative thermal protection systems for space vehicles.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Ananda S. Vaka, Suvankar Ganguly, Prabal Talukdar
Summary: A novel methodology using an inverse heat transfer technique based on Salp Swarm Algorithm (SSA) has been proposed to predict the variable interfacial heat flux of a three-dimensional mould domain. This method allows for a more accurate estimation of unknown boundary heat flux in a continuous casting process, particularly in corner heat flux aspects.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Tokuma Hikata, Hitoshi Fujimoto
Summary: Water-jet quenching is commonly used in steel-manufacturing industries for cooling hot solids. Evaluating the surface heat flux in the jet-impact region is necessary for precise temperature control. In this study, a method for evaluating the surface heat flux was developed, which showed high spatial resolution and was validated through experiments.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Pei Zhang, Chuang Sun, Xin-Lin Xia
Summary: The particle filter (PF) and improved algorithm (unscented particle filter (UPF)) are used for predicting transient heat flux (q(t)) on the boundary of participating medium. The study considers the temperature-dependent thermophysical properties and graded index medium. The UPF algorithm, with unscented Kalman filter, outperforms the PF algorithm in terms of stability and accuracy.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Camila F. Gomez, Rens Nieuwenhuizen, Cees W. M. van der Geld, Hans G. M. Kuerten, Mustafa Bsibsi, Bart P. M. van Esch
Summary: This paper systematically investigates sources of inaccuracy in solving the IHCP and their impact on heat flux estimations, proposing two measures to avoid misinterpretations in quenching heat flux estimations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Naoko Iwata, Fabio Bozzoli, Luca Pagliarini, Luca Cattani, Pamela Vocale, Matteo Malavasi, Sara Rainieri
Summary: This study focused on the local heat flux distributions and heat transfer behavior of Pulsating Heat Pipes (PHPs), exploring characteristics such as fluid oscillation frequencies under different heat input conditions. The results provide valuable insights into the fundamental governing mechanisms of PHPs.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Jinghui Han, Long Xu, Kaiwei Cao, Tianxiang Li, Xianhua Tan, Zirong Tang, Tielin Shi, Guanglan Liao
Summary: This paper introduces a LSTM-based encoder-decoder scheme for online estimation of heat flux during turning, utilizing mathematical-physical models and finite element models to generate training datasets. Numerical tests and experimental validations demonstrate the potential of the LSTM-ED method for online heat flux monitoring in scientific research and industrial production, outperforming other artificial intelligence methods.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Roberto Baccoli, Amit Kumar, Anna Concas, Gianluca Gatto, Nicola Pintus, Andrea Medda, Giuseppe Rodriguez
Summary: In this study, an original experimental device coupled with an optimization technique was developed to determine the thermal diffusivity of solid materials. The inverse problem of the classical Fourier heat equation was successfully solved using numerical supervision and an optimization procedure. The results show that incorporating heat loss corrections significantly improves the estimation of thermal diffusivity and increases the agreement with experimental data.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Chengbo Zhang, Binbin Hou, Lei Shao, Zongshu Zou, Henrik Saxen
Summary: The undisturbed and well-controlled hearth state is crucial for the operation of an ironmaking blast furnace. A wear model was developed to estimate the hearth state of a three-taphole blast furnace. The model uses thermocouple readings and solves an inverse heat conduction problem to optimize the erosion and skull lines. The results showed excessive erosion in the hearth periphery and low permeability in the core of the deadman.
Article
Energy & Fuels
Mohadeseh Seyednezhad, Hamidreza Najafi
Summary: This study evaluates the performance of a TE-based radiant cooling and heating system for building applications in terms of energy and economics. The system has a higher initial cost compared to traditional systems, but offers potential attractiveness due to its benefits.
Article
Thermodynamics
Obinna Uyanna, Hamidreza Najafi
Summary: A novel approach using Tikhonov regularization method and filter coefficients has been proposed, which can accurately estimate heat flux in a one-dimensional domain with moving boundary and temperature dependent material properties. The method is computationally efficient and offers real-time operation, making it suitable for applications such as ablative thermal protection systems for space vehicles.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Energy & Fuels
Puyi Yang, Hamidreza Najafi
Summary: This paper compares four wake models selected from FLORIS by applying three classical WFLO scenarios. The results show that while the Jensen wake model is the fastest, it underestimates the velocity deficit, the multi-zone model requires additional tuning on the parameters, and the Gaussian-curl hybrid wake model does not provide significant improvement in the current study.
JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Energy & Fuels
Puyi Yang, Hamidreza Najafi
Summary: This paper compares two types of multi-stage methods for wind farm layout optimization problems and uses annual energy production as the objective function. The results show that the D-C models achieve an average increase of 0.67% in AEP and an average reduction of 6.2% in computational time compared to the H-G models.
JOURNAL OF ENERGY RESOURCES TECHNOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Energy & Fuels
Ahmad Golrokh Sani, Hamidreza Najafi, Seyedeh Shakiba Azimi
Summary: In this study, dynamic thermal modeling of a liquefied CO2 insulated-body tanker truck was conducted to provide a more precise estimation of heat leak quantity, pressure build-up, refrigeration cooling demand, and energy consumption.
Article
Energy & Fuels
Benjamin Kubwimana, Hamidreza Najafi
Summary: This paper presents a novel approach for the global optimization of building energy models (BEMs) using Python EnergyPlus. A Python-based script is developed to automate the data entry into EnergyPlus and simulate numerous possible designs. The resulting datasets are used to establish a surrogate BEM optimized through Bayesian optimization and a genetic algorithm. The proposed approach bridges the gap between physics-based building energy models and powerful optimization tools in Python, allowing for computationally efficient global optimization.
Article
Energy & Fuels
Benjamin Kubwimana, Mohadeseh Seyednezhad, Hamidreza Najafi
Summary: This paper presents a comprehensive investigation of the performance of a radiant cooling ceiling panel working on thermoelectric principles. The numerical modeling and analysis, along with experimental validation, show that the TE-based radiant cooling system can achieve the desired thermal comfort levels under various operating conditions.
Article
Agricultural Engineering
Hamidreza Najafi, Ahmad Golrokh Sani, Mohammad Amin Sobati
Summary: This study compared the quantitative and qualitative characteristics of sugarcane residues, focusing on their thermal decomposition. The suitability of the samples as feedstock for pyrolysis was evaluated using various analyses. The molecular structure and main fragments of the samples were compared and their interactions on the thermal stability were determined. The results provide reliable information for the design and optimization of thermal conversion processes using different sugarcane residues.
INDUSTRIAL CROPS AND PRODUCTS
(2023)
Article
Chemistry, Multidisciplinary
Reza Behmadi, Masoud Mirzaei, M. Reza Afshar, Hamidreza Najafi
Summary: This research focused on improving the morphology of molybdenum trioxide (MoO3) through the purification of molybdenite concentrate using nitric acid leaching. By conducting experiments with response surface methodology, the effects of temperature, time, and acid molarity were analyzed. The results showed that the leaching process significantly reduced the chalcopyrite content in the concentrate, leading to the enhancement of the length of purified MoO3 microfibers.
Article
Energy & Fuels
Reza Behmadi, Masoud Mirzaei, M. Reza Afshar, Hamidreza Najafi
Summary: The top-down approach was used to develop catalysts for higher alcohol synthesis. The process of chemical leaching and exfoliation successfully reduced impurities and improved the selectivity and activity of the catalysts.
Article
Thermodynamics
Hamidreza Najafi, John Constantinide, Bruce Lindsay
Summary: This article introduces the application of the ASHRAE Building EQ platform in various types of buildings and illustrates using a case study how it was used for conducting Level 1 Energy Audits and providing practical experience to engineering students.
Article
Thermodynamics
Mahsa Taghavi, Swapnil Sharma, Vemuri Balakotaiah
Summary: This study investigates the natural convection effects in the insulation layers of spherical storage tanks and their impact on the tanks' performance. The permeability and Rayleigh number of the insulation material are considered as key factors. The results show that as the Rayleigh number increases, new convective cells emerge and cause the cold boundary to approach the external hot boundary. In the case of large temperature differences, multiple solutions may coexist.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyang Xu, Fangjun Hong, Chaoyang Zhang
Summary: This study introduces a self-induced jet impingement device for enhancing pool boiling performance in high power electronic cooling. Through visualization and parametric investigations, the effects of this device on pool boiling performance are studied, revealing the promotion of additional liquid supply and vapor exhausting. The flow rate of the liquid jet is found to positively impact boiling performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Wenchao Ke, Yuan Liu, Fissha Biruke Teshome, Zhi Zeng
Summary: Underwater wet laser welding (UWLW) is a promising and labor-saving repair technique. A thermal multi-phase flow model was developed to study the heat transfer, fluid dynamics, and phase transitions during UWLW. The results show that UWLW creates a water keyhole, making the welding environment similar to in air laser welding.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Xingrong Lian, Lin Tian, Zengyao Li, Xinpeng Zhao
Summary: This study investigates the heat transfer mechanisms in natural fiber-derived porous structures and finds that thermal radiation has a significant impact on the thermal conductivity in low-density regions, while natural convection rarely occurs. Insulation materials derived from micron-sized natural fibers can achieve minimum thermal conductivity at specific densities. Strategies to lower the thermal conductivity include increasing porosity and incorporating nanoscale pores using nanosize fibers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Yasir A. Malik, Kilian Koebschall, Stephan Bansmer, Cameron Tropea, Jeanette Hussong, Philippe Villedieu
Summary: Ice crystal icing is a significant hazard in aviation, and accurate modeling of sticking efficiency is essential. In this study, icing wind tunnel experiments were conducted to quantify the volumetric liquid water fraction, sticking efficiency, and maximum thickness of ice layers. Two measurement techniques, calorimetry and capacitive measurements, were used to measure the liquid water content and distribution in the ice layers. The experiments showed that increasing wet bulb temperatures and substrate heat flux significantly increased sticking efficiency and maximum ice layer thickness.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinqi Hu, Tongtong Geng, Kun Wang, Yuanhong Fan, Chunhua Min, Hsien Chin Su
Summary: This study experimentally examined the heat dissipation of vibrating fans and demonstrated its inherent mechanism through numerical simulation. The results showed that the flow fields induced by the vibrating blades exhibited pulsating features and formed large-scale and small-scale vortical structures, significantly improving heat dissipation. The study also identified the impacts of different blade structures and developed a trapezoidal-folding blade, which effectively reduced the maximum temperature of the heat source and alleviated high-temperature failure crisis.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Dan-Dan Su, Xiao-Bin Li, Hong-Na Zhang, Feng-Chen Li
Summary: The boiling heat transfer of low-boiling-point working fluid is a common heat dissipation technology in electronic equipment cooling. This study analyzed the interfacial boiling behavior of R134a under different conditions and found that factors such as the initial thickness of the liquid film, solid-liquid interaction force, and initial temperature significantly affect the boiling mode and thermal resistance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyi Wu, Dongke Sun, Wei Chen, Zhenhua Chai
Summary: A unified lattice Boltzmann-phase field scheme is proposed to simulate dendrite growth of binary alloys in the presence of melt convection. The effects of various factors on the growth are investigated numerically, and the model is validated through comparisons and examinations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shaokun Ge, Ya Ni, Fubao Zhou, Wangzhaonan Shen, Jia Li, Fengqi Guo, Bobo Shi
Summary: This study investigated the temperature distribution of main cables in a suspension bridge during fire scenarios and proposed a prediction model for the maximum temperature of cables in different lane fires. The results showed that vehicle fires in the emergency lane posed a greater thermal threat to the cables.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shuang-Ying Wu, Shi-Yao Zhou, Lan Xiao, Jia Luo
Summary: This paper investigates the two-phase flow and heat transfer characteristics of low-velocity jet impacting on a cylindrical surface. The study reveals that the heat transfer regimes are non-phase transition and nucleate boiling with the increase of heat transfer rate. The effects of jet impact height and outlet velocity on local surface temperatures are pronounced at the non-phase transition stage. The growth rates of heat transfer rate and liquid loss rate increase significantly from the non-phase transition to nucleate boiling stage.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Emad Hasani Malekshah, Wlodzimierz Wlodzimierz, Miros law Majkut
Summary: Cavitation has significant practical importance and can be controlled by air injection. This study investigates the natural to ventilated cavitation process around a hydrofoil through numerical and experimental methods. The results show that the location and rate of air injection have a meaningful impact on the characteristics of cavitation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Feriel Yahiat, Pascale Bouvier, Antoine Beauvillier, Serge Russeil, Christophe Andre, Daniel Bougeard
Summary: This study explores the enhancement of mixing performance in laminar flow equipment by investigating the generation of chaotic advection using wall deformations in annular geometries. The findings demonstrate that the combined geometry can achieve perfect mixing at various Reynolds numbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Hui He, Ning Lyu, Caihua Liang, Feng Wang, Xiaosong Zhang
Summary: This study investigates the condensation, frosting, and defrosting processes on superhydrophobic surfaces with millimeter-scale structures. The results reveal that the structures can influence the growth and removal of frost crystals, with the bottom grooves creating a frost-free zone and conical edges promoting higher frost crystal heights. Two effective methods for defrosting are observed: hand-lifting the groove and airfoil retraction contraction on protruding structures. This research provides valuable insights into frost formation and defrosting on millimeter-structured superhydrophobic surfaces, with potential applications in anti-frost engineering.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Thiwanka Arepolage, Christophe Verdy, Thibaut Sylvestre, Aymeric Leray, Sebastien Euphrasie
Summary: This study developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, the desired local density-heat capacity product and anisotropic thermal conductivities were achieved. The homogenized thermal conductivities were obtained from finite element simulations and cylindrical symmetry consideration. A 3D concentrator was fabricated using 3D metal printing and characterized using a thermal camera. Compared to devices that solely consider anisotropic conductivities, the time evolution characteristics of the metadevice designed with coordinate transformation were closer to those of an ideal concentrator.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Liangyuan Cheng, Qingyang Wang, Jinliang Xu
Summary: In this study, we investigated the supercritical heat transfer of CO2 in a horizontal tube with a diameter of 10.0 mm, covering a wide range of pressures, mass fluxes, and heat fluxes. The study revealed a non-monotonic increase in wall temperatures along the flow direction and observed both positive and negative wall temperature differences between the bottom and top tube. The findings were explained by the thermal conduction in the solid wall interacting with the stratified-wavy flow in the tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
