Pub Date : 2024-11-06DOI: 10.1016/j.csite.2024.105348
Hanifa Hanif , Ruishi Liang , Rahimah Mahat
This research aims to increase the heat transfer capacity of a fluid flow over a Riga plate using ( ) hybrid nanoparticles. It will also explain how the hybrid nanofluid behaves in the presence of suction/injection and thermal slip parameters. Furthermore, fluid dynamics and heat transfer across a Riga plate will be compared to a normal plate. The modeled problem is solved umerically using the Crank–Nicolson method and the simulations are done in MATLAB. The numerical findings reveal that the drag forces can be controlled using a Riga plate over a normal plate. It is also observed that the tiny nanoparticles enhance the thermal performance. When considering the Riga plate, heat transfer rates of all fluids increased by approximately 5%. The heat transfer rate of is 4.2% and 0.2% greater than H2O and , respectively.
{"title":"Dynamics of Ag–TiO2/water hybrid nanofluid flow over a Riga plate","authors":"Hanifa Hanif , Ruishi Liang , Rahimah Mahat","doi":"10.1016/j.csite.2024.105348","DOIUrl":"10.1016/j.csite.2024.105348","url":null,"abstract":"<div><div>This research aims to increase the heat transfer capacity of a fluid flow over a Riga plate using ( <figure><img></figure> ) hybrid nanoparticles. It will also explain how the hybrid nanofluid behaves in the presence of suction/injection and thermal slip parameters. Furthermore, fluid dynamics and heat transfer across a Riga plate will be compared to a normal plate. The modeled problem is solved umerically using the Crank–Nicolson method and the simulations are done in MATLAB. The numerical findings reveal that the drag forces can be controlled using a Riga plate over a normal plate. It is also observed that the tiny nanoparticles enhance the thermal performance. When considering the Riga plate, heat transfer rates of all fluids increased by approximately 5%. The heat transfer rate of <figure><img></figure> is 4.2% and 0.2% greater than H<sub>2</sub>O and <figure><img></figure> , respectively.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105348"},"PeriodicalIF":6.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.csite.2024.105437
Jianwei Yue , Jiahui Liu , Xiao Song , Chao Yan
This study introduces a novel design methodology for composite insulation material aimed at reducing the operational energy consumption of buildings. Vacuum Insulation Panels (VIPs) are recognized for their excellent insulating properties due to their vacuum-sealed nature that minimizes thermal transmittance. However, VIPs are susceptible to damage from temperature stress and abrasion, which can compromise vacuum integrity and degrade performance over time. To mitigate this, a protective layer of rock wool board is adhered to the exterior of the VIP to create a composite insulation material. The thermal conductivity characteristics of the composite insulation materials are experimentally measured and then corroborated with simulations using ANSYS software to affirm the precision of finite element analysis methods. A composite Insulation wall model is constructed using ANSYS to analyze the impact of varying the thickness of the composite insulation materials and the pressure within the VIP on thermal performance. The findings demonstrate that the thermal transmittance coefficient of the composite insulated wall diminishes with increased insulation material thickness and rises with increased pressure within the VIP. Additionally, rock wool boards significantly enhance the durability of the composite insulation material.
{"title":"Research on the design and thermal performance of vacuum insulation panel composite insulation materials","authors":"Jianwei Yue , Jiahui Liu , Xiao Song , Chao Yan","doi":"10.1016/j.csite.2024.105437","DOIUrl":"10.1016/j.csite.2024.105437","url":null,"abstract":"<div><div>This study introduces a novel design methodology for composite insulation material aimed at reducing the operational energy consumption of buildings. Vacuum Insulation Panels (VIPs) are recognized for their excellent insulating properties due to their vacuum-sealed nature that minimizes thermal transmittance. However, VIPs are susceptible to damage from temperature stress and abrasion, which can compromise vacuum integrity and degrade performance over time. To mitigate this, a protective layer of rock wool board is adhered to the exterior of the VIP to create a composite insulation material. The thermal conductivity characteristics of the composite insulation materials are experimentally measured and then corroborated with simulations using ANSYS software to affirm the precision of finite element analysis methods. A composite Insulation wall model is constructed using ANSYS to analyze the impact of varying the thickness of the composite insulation materials and the pressure within the VIP on thermal performance. The findings demonstrate that the thermal transmittance coefficient of the composite insulated wall diminishes with increased insulation material thickness and rises with increased pressure within the VIP. Additionally, rock wool boards significantly enhance the durability of the composite insulation material.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105437"},"PeriodicalIF":6.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.csite.2024.105406
Abdelwaheb Hadou , Ahmed Belaadi , Ibrahim M.H. Alshaikh , Djamel Ghernaout
This study evaluated the thermokinetic and thermodynamic properties of Dracaena draco fibers (DDFs) through thermogravimetric analysis (TGA). The DDFs underwent non-isothermal heating in a nitrogen atmosphere, with 5, 10, and 20 °C/min heating rates starting at 20 °C and reaching 800 °C. TGA analysis demonstrated that the pyrolysis of DDFs took place in three clearly defined phases: dehydration, devolatilization, and solid biochar. The thermokinetic and thermodynamic properties were computed for the devolatilization phase of mass reduction. The Coats-Redfern technique employed twenty-one separate kinetic equations derived from four fundamental solid-state reaction processes. Out of all the diffusivity models (DMs), the Ginstlinge-Brounshtein (DM5), Jander (3D diffusion) (DM7), and Ginstling models (DM8) had the best fit, as indicated by their highest coefficient of regression values (R2 > 0.990) across all the three heating rates. The activation energy values found by the DM5, DM7, and DM8 models are 76.5, 82.32, and 76.47 kJ/mol, respectively, for the 5 °C/min heating rate. The thermodynamic variables, including the entropy, free energy, and enthalpy change, were calculated based on the kinetic data. The study’s findings are significant for evaluating the DDFs' potential as an energy source, constructing reactors, producing chemicals, and understanding the DDFs’s features for composite synthesis.
{"title":"Pyrolysis features of Dracaena draco lignocellulosic fibers: Kinetic and thermodynamic analysis at various heating rates through coats-redfern method","authors":"Abdelwaheb Hadou , Ahmed Belaadi , Ibrahim M.H. Alshaikh , Djamel Ghernaout","doi":"10.1016/j.csite.2024.105406","DOIUrl":"10.1016/j.csite.2024.105406","url":null,"abstract":"<div><div>This study evaluated the thermokinetic and thermodynamic properties of <em>Dracaena draco</em> fibers (DDFs) through thermogravimetric analysis (TGA). The DDFs underwent non-isothermal heating in a nitrogen atmosphere, with 5, 10, and 20 °C/min heating rates starting at 20 °C and reaching 800 °C. TGA analysis demonstrated that the pyrolysis of DDFs took place in three clearly defined phases: dehydration, devolatilization, and solid biochar. The thermokinetic and thermodynamic properties were computed for the devolatilization phase of mass reduction. The Coats-Redfern technique employed twenty-one separate kinetic equations derived from four fundamental solid-state reaction processes. Out of all the diffusivity models (DMs), the Ginstlinge-Brounshtein (DM5), Jander (3D diffusion) (DM7), and Ginstling models (DM8) had the best fit, as indicated by their highest coefficient of regression values (<em>R</em><sup>2</sup> > 0.990) across all the three heating rates. The activation energy values found by the DM5, DM7, and DM8 models are 76.5, 82.32, and 76.47 kJ/mol, respectively, for the 5 °C/min heating rate. The thermodynamic variables, including the entropy, free energy, and enthalpy change, were calculated based on the kinetic data. The study’s findings are significant for evaluating the DDFs' potential as an energy source, constructing reactors, producing chemicals, and understanding the DDFs’s features for composite synthesis.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105406"},"PeriodicalIF":6.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.csite.2024.105447
Muhammad Shahbaz , Muddasser Inayat , Dagmar Juchelkov , Usama Ahmed , David Hughes , Imtiaz Ali , Salman Raza Naqvi
Managing high-ash sludge from tanneries is a significant challenge and requires investigating their conversion to valuable goods. This study explores the use of gasification processes to convert tannery waste into syngas and the use of syngas for power generation. In this respect, the integrated process thermal equilibrium simulation model has been developed using the Aspen Plus® V12. This model consists of (1) a steam gasification model for syngas production and (2) a power generation model for converting syngas into electricity. In addition, sensitivity analysis has been carried out to determine the effects of temperature (650–900 °C), steam flow (500–2000 kg/h), and CaO flow (0.1500 kg/h) on the composition and power generation of syngas. Changes in steam flow rate at constant temperature (cao flow rate 1500 kg/h) show an increase in H2 content to 80 % and a decline in CO and CH4 content. This increases total power output from 3680 kW to 4001 kW, temperature increases from 650 to 900 °C, and steam flow increases from 500 to 2000 kg/h from 3500 to 4600 kW. Finally, the impact of CaO as a sorbent is significant in electricity generation and CO2 mitigation, increasing to over 600 kW of energy output. This work could contribute to converting waste into energy, which could have a significant financial impact on the tannery industry.
{"title":"Analysis of syngas and power production from tannery waste via gasification process using integrated thermal equilibrium simulation model","authors":"Muhammad Shahbaz , Muddasser Inayat , Dagmar Juchelkov , Usama Ahmed , David Hughes , Imtiaz Ali , Salman Raza Naqvi","doi":"10.1016/j.csite.2024.105447","DOIUrl":"10.1016/j.csite.2024.105447","url":null,"abstract":"<div><div>Managing high-ash sludge from tanneries is a significant challenge and requires investigating their conversion to valuable goods. This study explores the use of gasification processes to convert tannery waste into syngas and the use of syngas for power generation. In this respect, the integrated process thermal equilibrium simulation model has been developed using the Aspen Plus® V12. This model consists of (1) a steam gasification model for syngas production and (2) a power generation model for converting syngas into electricity. In addition, sensitivity analysis has been carried out to determine the effects of temperature (650–900 °C), steam flow (500–2000 kg/h), and CaO flow (0.1500 kg/h) on the composition and power generation of syngas. Changes in steam flow rate at constant temperature (cao flow rate 1500 kg/h) show an increase in H<sub>2</sub> content to 80 % and a decline in CO and CH<sub>4</sub> content. This increases total power output from 3680 kW to 4001 kW, temperature increases from 650 to 900 °C, and steam flow increases from 500 to 2000 kg/h from 3500 to 4600 kW. Finally, the impact of CaO as a sorbent is significant in electricity generation and CO<sub>2</sub> mitigation, increasing to over 600 kW of energy output. This work could contribute to converting waste into energy, which could have a significant financial impact on the tannery industry.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105447"},"PeriodicalIF":6.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.csite.2024.105411
Muhammad Asif Zahoor Raja , Atifa Latif , Muntaha Khalid , Kottakkaran Sooppy Nisar , Muhammad Shoaib
This study aims to develop an efficient predictive model for Cattaneo-Christov heat and mass transformation of dissipative Williamson fluid with the effects of double stratification (CCHMT-DWF-DS) using the Levenberg-Marquardt Backpropagation (LMA-BP) algorithm. The under-consideration Williamson fluid flow is magneto-hydro-dynamic, incompressible and two-dimensional through a stretching sheet. The mathematical model of nonlinear partial differential equations for physical phenomena is transformed into ordinary differential equations by means of renowned similarity transformations. The solutions of physical problem are computed by bvp4c technique through MATLAB. The LMA-BP is employed to train a backward neural network capable of accurately predicting velocity, temperature, and concentration profiles under various physical conditions such as changes in the Hartmann number , Prandtl number , Schmidt number , Williamson parameter , the relaxation time of temperature , the relaxation time of concentration , temperature stratification , and concentration stratification for generating a variety of graphical outcomes and statistics. This research is significant for its innovative use of the LMA-BP in analyzing the complex dynamics of non-Newtonian fluids specifically the Williamson fluid, alongside the Cattaneo-Christov heat and mass flux model. The obtaining graphs have been discussed in detail. The thermal and solutal relaxation factors reduce heat and mass flow while fluid motion is delayed by the time-dependent parameter and further reduced by the Hartman number. The Cattaneo-Christov heat flux model enhances simulation accuracy by integrating temporal delays in heat transfer, proving beneficial for sophisticated industrial and scientific endeavors related to non-Newtonian fluids. This analysis offers a powerful predictive tool for applications in thermal management, industrial cooling systems, and biomedical fluid dynamics, advancing machine learning in fluid mechanics.
{"title":"Intelligent predictive networks for Cattaneo-Christov heat and mass transfer dissipated Williamson fluid through double stratification","authors":"Muhammad Asif Zahoor Raja , Atifa Latif , Muntaha Khalid , Kottakkaran Sooppy Nisar , Muhammad Shoaib","doi":"10.1016/j.csite.2024.105411","DOIUrl":"10.1016/j.csite.2024.105411","url":null,"abstract":"<div><div>This study aims to develop an efficient predictive model for Cattaneo-Christov heat and mass transformation of dissipative Williamson fluid with the effects of double stratification (CCHMT-DWF-DS) using the Levenberg-Marquardt Backpropagation (LMA-BP) algorithm. The under-consideration Williamson fluid flow is magneto-hydro-dynamic, incompressible and two-dimensional through a stretching sheet. The mathematical model of nonlinear partial differential equations for physical phenomena is transformed into ordinary differential equations by means of renowned similarity transformations. The solutions of physical problem are computed by bvp4c technique through MATLAB. The LMA-BP is employed to train a backward neural network capable of accurately predicting velocity, temperature, and concentration profiles under various physical conditions such as changes in the Hartmann number <span><math><mrow><mi>H</mi><mi>a</mi></mrow></math></span>, Prandtl number <span><math><mrow><mi>Pr</mi></mrow></math></span>, Schmidt number <span><math><mrow><mi>S</mi><mi>c</mi></mrow></math></span>, Williamson parameter <span><math><mrow><mi>λ</mi></mrow></math></span>, the relaxation time of temperature <span><math><mrow><msub><mi>γ</mi><mn>1</mn></msub></mrow></math></span>, the relaxation time of concentration <span><math><mrow><msub><mi>γ</mi><mn>2</mn></msub></mrow></math></span>, temperature stratification <span><math><mrow><msub><mi>δ</mi><mn>1</mn></msub></mrow></math></span>, and concentration stratification <span><math><mrow><msub><mi>δ</mi><mn>2</mn></msub></mrow></math></span> for generating a variety of graphical outcomes and statistics. This research is significant for its innovative use of the LMA-BP in analyzing the complex dynamics of non-Newtonian fluids specifically the Williamson fluid, alongside the Cattaneo-Christov heat and mass flux model. The obtaining graphs have been discussed in detail. The thermal and solutal relaxation factors reduce heat and mass flow while fluid motion is delayed by the time-dependent parameter <span><math><mrow><mi>λ</mi></mrow></math></span> and further reduced by the Hartman number. The Cattaneo-Christov heat flux model enhances simulation accuracy by integrating temporal delays in heat transfer, proving beneficial for sophisticated industrial and scientific endeavors related to non-Newtonian fluids. This analysis offers a powerful predictive tool for applications in thermal management, industrial cooling systems, and biomedical fluid dynamics, advancing machine learning in fluid mechanics.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105411"},"PeriodicalIF":6.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659786","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.csite.2024.105404
Nurul Syakirah Nazri , Ahmad Fudholi , Muslizainun Mustapha , Mohd Fadhli Shah Khaidzir , Muhamad Hafiz Hamsan , Kar Keng Lim , Afifuddin Husairi Hussain , Ubaidah Syafiq , Amir Azirul Bin Narulhizam , Masita Mohammad , Nurul Nazli Rosli , Kamaruzzaman Sopian
This research evaluates the performance of a hybrid thermal-thermoelectric photovoltaic air collector system (PV/T-TE) through experimental investigations. By integrating photovoltaic (PV) panels with thermoelectric (TE) modules, the system aims to enhance efficiency and energy output by converting waste heat into additional electricity. The study examines the impact of radiation intensity, ranging from 455.65 to 795.18 W/m2, on the system's performance, utilizing output temperature (To) and plate temperature (Tp) as key metrics. Managing waste heat in PV technology remains a challenge, impacting efficiency. Traditional PV/T systems generate both electricity and thermal energy but suffer efficiency losses due to inadequate heat management. Integrating TE modules into PV/T systems offers a promising solution, but optimal configurations and performance impacts under varying conditions are underexplored. Limited research focuses on PV/T-TE hybrid systems, with most studies addressing PV-TE systems. The objectives of this research are to experimentally assess the impact of integrating TE modules on the thermal and electrical efficiency of PV/T systems under varying radiation intensities and air mass flow rates. The methodology involves setting up a PV/T-TE hybrid system, conducting experiments under controlled conditions, and analyzing key performance metrics. The study explores optimal TE module configurations and installation techniques to maximize heat transfer and electricity generation. Comparative analysis with conventional PV/T systems establishes the superiority of the hybrid system. Findings indicate significant benefits from incorporating TE modules, enhancing energy output and efficiency by maintaining optimal PV panel temperatures.
本研究通过实验研究评估了热电混合光伏空气集热器系统（PV/T-TE）的性能。该系统将光伏（PV）面板与热电（TE）模块集成在一起，旨在通过将废热转化为额外的电力来提高效率和能量输出。研究利用输出温度（To）和板温（Tp）作为关键指标，考察了辐射强度（455.65 至 795.18 W/m2）对系统性能的影响。光伏技术中的余热管理仍然是一项挑战，会影响效率。传统的 PV/T 系统既能发电又能产生热能，但由于热量管理不足而导致效率损失。将 TE 模块集成到 PV/T 系统中提供了一个很有前景的解决方案，但最佳配置和不同条件下的性能影响还未得到充分探索。针对光伏/TE 混合系统的研究有限，大多数研究都是针对光伏-TE 系统。本研究的目标是通过实验评估在不同辐射强度和空气质量流量条件下，集成 TE 模块对 PV/T 系统热效率和电效率的影响。研究方法包括建立光伏/TE 混合系统，在受控条件下进行实验，并分析关键性能指标。该研究探讨了 TE 模块的最佳配置和安装技术，以实现传热和发电的最大化。与传统 PV/T 系统的对比分析证明了混合系统的优越性。研究结果表明，采用 TE 模块具有显著优势，可通过保持最佳光伏板温度来提高能量输出和效率。
{"title":"Bridging the gap: A comparative analysis of indoor and outdoor performance for photovoltaic-thermal-thermoelectric hybrid systems","authors":"Nurul Syakirah Nazri , Ahmad Fudholi , Muslizainun Mustapha , Mohd Fadhli Shah Khaidzir , Muhamad Hafiz Hamsan , Kar Keng Lim , Afifuddin Husairi Hussain , Ubaidah Syafiq , Amir Azirul Bin Narulhizam , Masita Mohammad , Nurul Nazli Rosli , Kamaruzzaman Sopian","doi":"10.1016/j.csite.2024.105404","DOIUrl":"10.1016/j.csite.2024.105404","url":null,"abstract":"<div><div>This research evaluates the performance of a hybrid thermal-thermoelectric photovoltaic air collector system (PV/T-TE) through experimental investigations. By integrating photovoltaic (PV) panels with thermoelectric (TE) modules, the system aims to enhance efficiency and energy output by converting waste heat into additional electricity. The study examines the impact of radiation intensity, ranging from 455.65 to 795.18 W/m<sup>2</sup>, on the system's performance, utilizing output temperature (T<sub>o</sub>) and plate temperature (T<sub>p</sub>) as key metrics. Managing waste heat in PV technology remains a challenge, impacting efficiency. Traditional PV/T systems generate both electricity and thermal energy but suffer efficiency losses due to inadequate heat management. Integrating TE modules into PV/T systems offers a promising solution, but optimal configurations and performance impacts under varying conditions are underexplored. Limited research focuses on PV/T-TE hybrid systems, with most studies addressing PV-TE systems. The objectives of this research are to experimentally assess the impact of integrating TE modules on the thermal and electrical efficiency of PV/T systems under varying radiation intensities and air mass flow rates. The methodology involves setting up a PV/T-TE hybrid system, conducting experiments under controlled conditions, and analyzing key performance metrics. The study explores optimal TE module configurations and installation techniques to maximize heat transfer and electricity generation. Comparative analysis with conventional PV/T systems establishes the superiority of the hybrid system. Findings indicate significant benefits from incorporating TE modules, enhancing energy output and efficiency by maintaining optimal PV panel temperatures.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105404"},"PeriodicalIF":6.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.csite.2024.105433
Vineet Tirth , Amina , Muhammad Kamran , Salhah Hamed Alrefaee , A.M. Quraishi , Dilsora Abduvalieva , Albandary Almahri , Naseem Akhter , Noureddine Elboughdiri , Rawaa M. Mohammed , Ali Algahtani , Hassan Alqahtani , N.M.A. Hadia , Abid Zaman
To identify a promising alternative to lead-based materials for solar cell application, we investigated the different physical properties of K2ScCoX6 (X = F, Cl) perovskites. Both materials have ferromagnetic ground state. The obtained optimize lattice constants are found to be 8.48 Å and 10.04 Å for K2ScCoF6 and K2ScCoCl6 respectively. Our finding indicate that these materials exhibit excellent structural, mechanical, the thermal stability, as evidenced by their Goldsmith's tolerance factor, elastic parameters, and negative formation energies. The formation energy is found to be -2.4 and -2.1 eV/atom for K2ScCoF6 and K2ScCoCl6 respectively. The electronic properties reveals that both materials have semiconducting nature. Notably, we observed low direct bandgap of 0.93 eV for K2ScCoF6 and 1.22 eV for K2ScCoCl6, which contrast with the typically large bandgap values reported for most halide double perovskite. The calculated values of Poisson's and Pugh's ratios, along with positive Cauchy's pressure, suggest a ductile nature for these compounds. Additionally, the optical properties show high absorption and optical conductivity, coupled with low reflectivity and minimal energy loss in lower energy ranges. These results suggest that the halogen-based double perovskite materials have significant potential as photovoltaic absorber materials in solar cell applications. Furthermore, their higher Seebeck coefficients, power factors and low thermal conductivity at room temperature underscore their potential for thermoelectric applications.
{"title":"Structural, electronic, magnetic, optical and thermoelectric properties of ferromagnetic double perovskites K2ScCoX6 (X = F, Cl): A first-principles study","authors":"Vineet Tirth , Amina , Muhammad Kamran , Salhah Hamed Alrefaee , A.M. Quraishi , Dilsora Abduvalieva , Albandary Almahri , Naseem Akhter , Noureddine Elboughdiri , Rawaa M. Mohammed , Ali Algahtani , Hassan Alqahtani , N.M.A. Hadia , Abid Zaman","doi":"10.1016/j.csite.2024.105433","DOIUrl":"10.1016/j.csite.2024.105433","url":null,"abstract":"<div><div>To identify a promising alternative to lead-based materials for solar cell application, we investigated the different physical properties of K<sub>2</sub>ScCoX<sub>6</sub> (X = F, Cl) perovskites. Both materials have ferromagnetic ground state. The obtained optimize lattice constants are found to be 8.48 Å and 10.04 Å for K<sub>2</sub>ScCoF<sub>6</sub> and K<sub>2</sub>ScCoCl<sub>6</sub> respectively. Our finding indicate that these materials exhibit excellent structural, mechanical, the thermal stability, as evidenced by their Goldsmith's tolerance factor, elastic parameters, and negative formation energies. The formation energy is found to be -2.4 and -2.1 eV/atom for K<sub>2</sub>ScCoF<sub>6</sub> and K<sub>2</sub>ScCoCl<sub>6</sub> respectively. The electronic properties reveals that both materials have semiconducting nature. Notably, we observed low direct bandgap of 0.93 eV for K<sub>2</sub>ScCoF<sub>6</sub> and 1.22 eV for K<sub>2</sub>ScCoCl<sub>6</sub>, which contrast with the typically large bandgap values reported for most halide double perovskite. The calculated values of Poisson's and Pugh's ratios, along with positive Cauchy's pressure, suggest a ductile nature for these compounds. Additionally, the optical properties show high absorption and optical conductivity, coupled with low reflectivity and minimal energy loss in lower energy ranges. These results suggest that the halogen-based double perovskite materials have significant potential as photovoltaic absorber materials in solar cell applications. Furthermore, their higher Seebeck coefficients, power factors and low thermal conductivity at room temperature underscore their potential for thermoelectric applications.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105433"},"PeriodicalIF":6.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-05DOI: 10.1016/j.csite.2024.105416
Ziyu Li, Yonggang Yu, An Chen
The modular charge is a novel charge system designed to cooperate with the automation of large-caliber guns. Using Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM), the motion and distribution of cylindrical particles driven by high-temperature, high-pressure gas during ignition and flame spreading were simulated in a two-module charge. Model validation was achieved through comparison with experimental data from simulated ignition experiments. Different ullage distributions were achieved by varying the axial distance between the primer and the first module. The results indicate that while maintaining a constant axial ullage between Module 1 and Module 2 (D2), increasing the axial distance between Module 1 and the primer (D1) leads to distinct changes in the particle packing structure. Particles stabilize in horizontal and steep slope accumulations from the breech to the front end of the combustion chamber in a stable state. However, the axil length of horizontal accumulation decreases linearly with increasing D1, and the axil length of steep slope accumulation shows a second-order polynomial relationship with D1. The inclination angle of the steep slope initially decreased and then increased. Axial ullage distribution affects the forces on the particles, velocities, and trajectories, resulting in uneven distribution within the combustion chamber.
{"title":"Effect of axial ullage distribution of modular charges on the dynamic behavior of cylindrical particles in the combustion chamber","authors":"Ziyu Li, Yonggang Yu, An Chen","doi":"10.1016/j.csite.2024.105416","DOIUrl":"10.1016/j.csite.2024.105416","url":null,"abstract":"<div><div>The modular charge is a novel charge system designed to cooperate with the automation of large-caliber guns. Using Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM), the motion and distribution of cylindrical particles driven by high-temperature, high-pressure gas during ignition and flame spreading were simulated in a two-module charge. Model validation was achieved through comparison with experimental data from simulated ignition experiments. Different ullage distributions were achieved by varying the axial distance between the primer and the first module. The results indicate that while maintaining a constant axial ullage between Module 1 and Module 2 (<em>D</em><sub>2</sub>), increasing the axial distance between Module 1 and the primer (<em>D</em><sub>1</sub>) leads to distinct changes in the particle packing structure. Particles stabilize in horizontal and steep slope accumulations from the breech to the front end of the combustion chamber in a stable state. However, the axil length of horizontal accumulation decreases linearly with increasing <em>D</em><sub>1</sub>, and the axil length of steep slope accumulation shows a second-order polynomial relationship with <em>D</em><sub>1</sub>. The inclination angle of the steep slope initially decreased and then increased. Axial ullage distribution affects the forces on the particles, velocities, and trajectories, resulting in uneven distribution within the combustion chamber.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105416"},"PeriodicalIF":6.4,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-05DOI: 10.1016/j.csite.2024.105415
Gan Cui , Yixuan Li , Qiaosheng Zhang , Juerui Yin , Di Wu , Xiao Xing , Jianguo Liu
As an ideal energy source, hydrogen is highly susceptible to spontaneous ignition once leaked, which is an urgent issue that needs to be addressed. Based on the shock tube model, this paper investigates flame propagation under various pressures, tube lengths, and diameters by employing the LES approach and a detailed hydrogen/air combustion mechanism. The results indicate that within the tube, the ignition kernels gradually evolve into tulip flames when specific conditions are satisfied. As pressure and tube length increase, the likelihood of forming a complete flame rises significantly; with the increase of tube diameter, the flame front is flatter and the flame intensity is more uniformly distributed. Furthermore, this paper develops a model to predict the formation of a complete flame: . Outside the tube, once the intact flame passes out of the tube and evolves into a jet flame, structures such as flame envelopes and jet vortices will appear. Higher release pressures make it more difficult for the flame to propagate steadily, whereas increasing tube length and diameter promotes combustion and sustains the flame outside the tube.
作为一种理想的能源，氢一旦泄漏极易自燃，这是一个亟待解决的问题。本文以冲击管模型为基础，采用 LES 方法和详细的氢气/空气燃烧机理，研究了不同压力、管子长度和直径下的火焰传播。结果表明，在满足特定条件的情况下，管内的点火核会逐渐演变成郁金香火焰。随着压力和管道长度的增加，形成完整火焰的可能性显著提高；随着管道直径的增加，火焰前沿更加平坦，火焰强度分布更加均匀。此外，本文还建立了一个预测完全火焰形成的模型：Pb/Pa=570.64(L/D)−0.6.在管外，完整火焰一旦冲出管外并演变成喷射火焰，就会出现火焰包络和喷射涡流等结构。较高的释放压力会使火焰更难稳定传播，而增加管道长度和直径则会促进燃烧并使火焰在管外持续燃烧。
{"title":"Study on characterization of flame propagation of spontaneous ignition caused by high-pressure hydrogen leakage","authors":"Gan Cui , Yixuan Li , Qiaosheng Zhang , Juerui Yin , Di Wu , Xiao Xing , Jianguo Liu","doi":"10.1016/j.csite.2024.105415","DOIUrl":"10.1016/j.csite.2024.105415","url":null,"abstract":"<div><div>As an ideal energy source, hydrogen is highly susceptible to spontaneous ignition once leaked, which is an urgent issue that needs to be addressed. Based on the shock tube model, this paper investigates flame propagation under various pressures, tube lengths, and diameters by employing the LES approach and a detailed hydrogen/air combustion mechanism. The results indicate that within the tube, the ignition kernels gradually evolve into tulip flames when specific conditions are satisfied. As pressure and tube length increase, the likelihood of forming a complete flame rises significantly; with the increase of tube diameter, the flame front is flatter and the flame intensity is more uniformly distributed. Furthermore, this paper develops a model to predict the formation of a complete flame: <span><math><mrow><msub><mi>P</mi><mi>b</mi></msub><mo>/</mo><msub><mi>P</mi><mi>a</mi></msub><mo>=</mo><mn>570.64</mn><msup><mrow><mo>(</mo><mrow><mi>L</mi><mo>/</mo><mi>D</mi></mrow><mo>)</mo></mrow><mrow><mo>−</mo><mn>0.6</mn></mrow></msup></mrow></math></span>. Outside the tube, once the intact flame passes out of the tube and evolves into a jet flame, structures such as flame envelopes and jet vortices will appear. Higher release pressures make it more difficult for the flame to propagate steadily, whereas increasing tube length and diameter promotes combustion and sustains the flame outside the tube.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105415"},"PeriodicalIF":6.4,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-05DOI: 10.1016/j.csite.2024.105412
Mehmet Onur Karaağaç
In rapidly developing economies, the increasing energy demand and fossil fuel consumption have made the need for renewable energy sources and efficient thermal energy storage (TES) solutions more urgent than ever. This study focuses on enhancing the thermal energy storage capabilities of paraffin-based phase change materials (PCMs) by incorporating Al2O3, MgO, and CuO nanoparticles. The evaluation of nano-enhanced PCMs focused on their melting temperatures, thermal storage capacities, thermal conductivities, and charge/discharge times. The experimental results revealed significant changes in the thermal properties of the nano-enhanced PCMs compared to pure paraffin. The melting temperature was raised by 2 °C due to Al2O3 nanoparticles, whereas CuO and MgO nanoparticles decreased it by 1.7 °C and 1.8 °C, respectively. Compared to pure paraffin, Al2O3-PW, MgO-PW, and CuO-PW exhibited improvements of 13 %, 39 %, and 48 % in thermal conductivities, respectively. CuO-doped paraffin showed an 11.8 % decrease in discharge time, suggesting its suitability for rapid heat transfer applications like defrosting systems or thermal management in electronics. On the other hand, paraffin doped with MgO showed a minimal 2.24 % reduction in discharge time, indicating its effectiveness in applications requiring heat retention, particularly for improved thermal insulation in building materials. The results highlighted the potential of nano-enhanced PCMs in energy storage and construction is underlined, offering a sustainable approach to improving energy efficiency in various sectors.
{"title":"Performance evaluation of nano-enhanced phase change materials for thermal energy storage: An experimental study","authors":"Mehmet Onur Karaağaç","doi":"10.1016/j.csite.2024.105412","DOIUrl":"10.1016/j.csite.2024.105412","url":null,"abstract":"<div><div>In rapidly developing economies, the increasing energy demand and fossil fuel consumption have made the need for renewable energy sources and efficient thermal energy storage (TES) solutions more urgent than ever. This study focuses on enhancing the thermal energy storage capabilities of paraffin-based phase change materials (PCMs) by incorporating Al<sub>2</sub>O<sub>3</sub>, MgO, and CuO nanoparticles. The evaluation of nano-enhanced PCMs focused on their melting temperatures, thermal storage capacities, thermal conductivities, and charge/discharge times. The experimental results revealed significant changes in the thermal properties of the nano-enhanced PCMs compared to pure paraffin. The melting temperature was raised by 2 °C due to Al<sub>2</sub>O<sub>3</sub> nanoparticles, whereas CuO and MgO nanoparticles decreased it by 1.7 °C and 1.8 °C, respectively. Compared to pure paraffin, Al<sub>2</sub>O<sub>3</sub>-PW, MgO-PW, and CuO-PW exhibited improvements of 13 %, 39 %, and 48 % in thermal conductivities, respectively. CuO-doped paraffin showed an 11.8 % decrease in discharge time, suggesting its suitability for rapid heat transfer applications like defrosting systems or thermal management in electronics. On the other hand, paraffin doped with MgO showed a minimal 2.24 % reduction in discharge time, indicating its effectiveness in applications requiring heat retention, particularly for improved thermal insulation in building materials. The results highlighted the potential of nano-enhanced PCMs in energy storage and construction is underlined, offering a sustainable approach to improving energy efficiency in various sectors.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"64 ","pages":"Article 105412"},"PeriodicalIF":6.4,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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