Thermal Science最新文献_第2页

Cattaneo-Christov heat flux effect on Sakiadis MHD boundary layer transport phenomena in the Jeffrey fluid Cattaneo-Christov热通量对Jeffrey流体中sakadiis MHD边界层输运现象的影响

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci221013214o

Zarith Othman, Zailan Siri, Muhamad Aziz, Kohilavani Naganthran

{"title":"Cattaneo-Christov heat flux effect on Sakiadis MHD boundary layer transport phenomena in the Jeffrey fluid","authors":"Zarith Othman, Zailan Siri, Muhamad Aziz, Kohilavani Naganthran","doi":"10.2298/tsci221013214o","DOIUrl":"https://doi.org/10.2298/tsci221013214o","url":null,"abstract":"This study aims to perform a numerical simulation of the boundary flow with the characteristic Sakiadis flow of the magnetohydrodynamic (MHD) Jeffrey fluid under the Cattaneo-Christov heat flux model over the horizontal plate. The similarity transformation for the local similarity solution was used to reduce the set of governing equations to non-linear ordinary differential equations. The equations were solved by using ?dsolve? command with the numeric option for the boundary value problem in Maple. Simulations have been carried out for different values of the relaxation to retardation times, the Deborah number, the magnetic field parameter, the heat flux relaxation time, the Prandtl number, and the Schmidt parameter. A comparative study of the numerical results from the previously published paper with the present result for the dimensionless velocity gradient over the horizontal plate shows excellent agreement. It has been found that the growth of the Deborah number leads to the dimensionless velocity gradient enhancement, while the increment of the relaxation to retardation times parameter and the magnetic field parameter indicates the opposite trend. The heat transfer rate noticeably decreased with an increment in the Prandtl number and thermal relaxation time at the fluid regime. Also, fluid concentration decreases with larger values of the Schmidt parameter.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136005808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of internally mounted helical fins on the separation performance of a cylindrical gas-solid cyclone separator 内装螺旋翅片对圆柱形气固旋风分离器分离性能的影响

4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci230527204f

Zeming Fu, Huagen Wu, Baohua Gao, Mengtao Liang, Guanghua Wu, Shuo Shang, Xin Zhang, Hongye Huang, Siwei Chen

{"title":"Effect of internally mounted helical fins on the separation performance of a cylindrical gas-solid cyclone separator","authors":"Zeming Fu, Huagen Wu, Baohua Gao, Mengtao Liang, Guanghua Wu, Shuo Shang, Xin Zhang, Hongye Huang, Siwei Chen","doi":"10.2298/tsci230527204f","DOIUrl":"https://doi.org/10.2298/tsci230527204f","url":null,"abstract":"In this study, an innovation was made by adding helical fins on the vortex finder of a cylindrical gas-solid cyclone separator, and the effect of this structural improvement on the separation performance was analyzed based on the flow field characteristics. The results show that both cyclones with and without helical fins exhibit a separation efficiency of almost 100 % for particles larger than 5 ?m. As the inlet velocity increases, the effect of adding helical fins on the overall separation efficiency decreases, with a relative deviation of only 0.16 % at an inlet velocity of 27 m/s, while it becomes increasingly effective in reducing energy consumption, with a pressure drop of 25.33 %. The mechanism of the overall performance improvement lies in the fact that the helical fins change the flow field distribution in the cyclone, where the turbulence intensity in the vortex finder is significantly reduced, the tangential velocity of the external vortex is decreased, and the pressure gradient is reduced. The purpose of this paper is to provide new ideas for the optimal design of the internal components of the cyclone separator.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136006063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A variational principle for fractal Klein-Gordon equation 分形Klein-Gordon方程的变分原理

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci2303803c

Qiaoling Chen

引用次数: 0

Assessment of detected in situ and modeled PM10/2.5 concentration levels during the urban transformation process in Novi Sad, Serbia 塞尔维亚诺维萨德城市转型过程中原位检测和模拟PM10/2.5浓度水平的评估

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci220215108s

Miljan Sunjevic, D. Reba, V. Rajs, B. Vujic, Milovan Ninkov, M. Vojinovic-Miloradov

{"title":"Assessment of detected in situ and modeled PM10/2.5 concentration levels during the urban transformation process in Novi Sad, Serbia","authors":"Miljan Sunjevic, D. Reba, V. Rajs, B. Vujic, Milovan Ninkov, M. Vojinovic-Miloradov","doi":"10.2298/tsci220215108s","DOIUrl":"https://doi.org/10.2298/tsci220215108s","url":null,"abstract":"Ambient air pollution is a very considerable and complex physicochemical and environmental issue. Particulate matter - PM is one of the fundamental pollutants constituted in ambient air. Rapidly expanding urban transformations in city of Novi Sad, Serbia, produces high concentrations of PM. The vast and growing number of construction sites as pollution emission hotspots induce constant nuisance for the people, build surrounding and environment in total. Serbian legislation has set PM pollution limit values for daily emissions, but the Air Pollutant Registry still doesn?t recognize construction sites as severe sources of PM emergence. Understanding the importance and the effects of PM emission from construction sites is crucial in environmental preservation. For the preparation and application of methods and techniques for prevention and mitigation, suitable environmental pollution modeling needs to be achieved. The aim of the research is to assess and determine the utility of Tier 1 prediction model designed by EPA and environmental modeling software ADMS - URBAN on observed construction sites in Novi Sad, Serbia. Assessing monitoring data confirms construction sites as significant PM 10 and PM2.5 pollution sources. Two sets of correction coefficients were calculated for PM10 and PM2.5, using average and median values, 2.56 - 2.54 and 1.03 - 0.97 respectively. The research study was for the first time conducted in Novi Sad, Serbia in the case of construction sites.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68236762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The role of microclimate in the formation of indoor air pollution 小气候在室内空气污染形成中的作用

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci220215105k

Oskars Kalva

{"title":"The role of microclimate in the formation of indoor air pollution","authors":"Oskars Kalva","doi":"10.2298/tsci220215105k","DOIUrl":"https://doi.org/10.2298/tsci220215105k","url":null,"abstract":"Indoor air quality plays a key role in assessing people's quality of life, as a large proportion of people spend up to 22 hours a day indoors and people are exposed to indoor air almost all day long [1]. People in developed countries spend much more time indoors. Recently, employers are paying more and more attention to ensuring the well - being of employees, as it affects the quality and productivity of their work [2, 3]. Ensuring an appropriate working environment on the part of employers ensures both sustainable social and economic links. Well-being can be affected by various parameters of the indoor environment, in addition to the microclimate, they can be - lighting, noise level, various odors. However, one of the primary indicators of comfort or discomfort in an indoor environment is thermal comfort or discomfort [4]. Gas stations were chosen as place for measurements because they are considered dangerous for several reasons: gas station territory is potentially hazardous with a high environmental risk and explosion hazard. Working shifts and nights is also considered undesirable for human health as it disrupts the biological rhythms in the human body [5]. In such circumstances, the indoor microclimate and air parameters play a very important role, as spending long hours in inappropriate microclimatic conditions is likely to lead to various long - term health problems for the workers.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68237204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A comparative study on 3E (energy, exergy and economic) analysis of solar PV operated dome-shaped solar stills 太阳能光伏运行的圆顶型太阳能蒸馏器3E(能源、能源和经济)分析比较研究

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci220502168p

Ragupathy Palaniappan, V. Murugesan, Kumaresan Govindasamy, Lakshmi Manirao

{"title":"A comparative study on 3E (energy, exergy and economic) analysis of solar PV operated dome-shaped solar stills","authors":"Ragupathy Palaniappan, V. Murugesan, Kumaresan Govindasamy, Lakshmi Manirao","doi":"10.2298/tsci220502168p","DOIUrl":"https://doi.org/10.2298/tsci220502168p","url":null,"abstract":"The present investigation centres on the empirical examination of a solar photovoltaic (PV) system that is integrated with a dome-shaped solar still (DSSS) in order to facilitate the process of desalination. The objective is to increase the production of freshwater through the utilisation of saline water at elevated temperatures. The assessment of the DSSS system's efficacy is conducted through the examination of various parameters, including water yield, energy, exergy, concentrator performance, and economic feasibility. The study's results demonstrate that the DSSS system's water yield, energy, and exergy were evaluated under varying inlet temperatures and mass flow rates. The study recorded the water yield, energy, and exergy at 4.73, 4.27, and 4.91 l/m?, respectively, with respect to the ambient inlet temperature. The water yield was observed to range from 6.9 to 7.7 litres per square metre under different input temperatures and air mass flow rates. The DSSS system's energy and exergy efficiency were evaluated, indicating encouraging results for various inlet air temperatures. Furthermore, the economic evaluation revealed that the rate of freshwater production was cost-effective in comparison to conventional solar stills. In summary, this research offers empirical proof of the efficacy of a solar photovoltaic-powered dome-shaped solar still for the purpose of desalination. It emphasises enhancements in the output of fresh water, energy and exergy efficiency, and the economic viability of this technology.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68243012","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An optimized method for TTSV placement with non-uniform heat sources in 3D-IC 3D-IC中非均匀热源TTSV的优化布置方法

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci220801021d

Feng Dai, Zhong-liang Pan

引用次数: 0

Linear frequency modulation infrared thermal imaging detection technology for GFRP/PMI foam sandwich structure defects 线性调频红外热成像检测GFRP/PMI泡沫夹层结构缺陷技术

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci220806007s

Yanping Song, Q. Tang, Chi-wu Bu, Yumei Lu, Peng Xu

{"title":"Linear frequency modulation infrared thermal imaging detection technology for GFRP/PMI foam sandwich structure defects","authors":"Yanping Song, Q. Tang, Chi-wu Bu, Yumei Lu, Peng Xu","doi":"10.2298/tsci220806007s","DOIUrl":"https://doi.org/10.2298/tsci220806007s","url":null,"abstract":"As one of the important structures of composite materials, PMI foam sandwich structure is prone to debonding and delamination defects during manufacturing and service, which seriously affects the mechanical properties of materials. Therefore, it is necessary to detect the defects of foam sandwich structure. A linear frequency modulation (LFM) infrared thermal wave nondestructive testing system was built to study the correlation between the geometric characteristics (diameter and depth) of the defect and the surface temperature signal and its influence on the detection effect. The image sequence is processed by principal component analysis, discrete Fourier transform, thermal wave signal reconstruction and other algorithms. Studies have shown that: the larger the defect diameter, the shallower the depth, easy to detect defects, detection effect is good. The detection system can effectively detect and identify debonding and delamination defects. The thermal wave signal reconstruction method is superior to the principal component analysis method and the discrete Fourier transform method in the signal-to-noise ratio (SNR)index, which improves the quality of the image and is conducive to the effective identification of the image surface defect information.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68246422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

CFD analysis of the effect of internal peak angle and mass flow rates on the thermal performance of solar air heater with triangle cross-section 内峰角和质量流量对三角截面太阳能空气加热器热性能影响的CFD分析

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci220918046a

Walid Amara, Yashar Aryanfar, H. Koten, A. Bouabidi, M. Chrigui, J. Alcaraz

{"title":"CFD analysis of the effect of internal peak angle and mass flow rates on the thermal performance of solar air heater with triangle cross-section","authors":"Walid Amara, Yashar Aryanfar, H. Koten, A. Bouabidi, M. Chrigui, J. Alcaraz","doi":"10.2298/tsci220918046a","DOIUrl":"https://doi.org/10.2298/tsci220918046a","url":null,"abstract":"A new design of Solar Air Heater (SAH) with triangle cross-section is numerically studied. The thermal performance of SAH is studied at various mass flow rates, inlet air temperatures and solar irradiation intensities. The CFD model is developed using the software ?ANSYS Fluent? to study the fluid flow and heat transfer in the solar air heater. 3D discretization is applied to study the thermal performance of solar collector with triangle cross section. Mesh independence is performed in order to choose the adequate mesh. The discrete ordinate radiation model (DOM) and the RNG k-? turbulence model are used to study the radiative heat transfer and the turbulent flow inside the SAH. Particularly, effects of different internal peak angles (145?,126?, 100?, 80? and 67.5?) under different solar irradiation intensities (from 620W/m^2 to 1081W/m^2) are studied to improve the thermal performance of the SAH. The results show a good agreement between the numerical model and the experimental data with an average error of 6%. The maximum outlet air temperature of the SAH reached 72?C for the geometries with 12 and 16 channels (Internal peak angles of 80? and 67.5?, respectively) under mass flow rate of 0.0264kg/s. The thermal performances of the SAH with 16 and 12 channels are 24.2% higher than standard geometry, respectively for solar irradiation intensity of 1081 W/m^2. The configuration with internal peak angle of 80? and 12 channels is selected as the optimal with a thermal efficiency of 79%, a low pressure drops compared to geometry with 16 channels and lower costs.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68248307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Flame and emission characteristics from NH3/CH4 combustion under ultrasonic excitation 超声波激励下NH3/CH4燃烧火焰及发射特性

IF 1.7 4区工程技术

Thermal Science Pub Date : 2023-01-01 DOI: 10.2298/tsci221008029s

Yi Su, Yifeng Chen, Chunjie Sui, Tianjiao bi, Wei Chen, Bin Zhang

{"title":"Flame and emission characteristics from NH3/CH4 combustion under ultrasonic excitation","authors":"Yi Su, Yifeng Chen, Chunjie Sui, Tianjiao bi, Wei Chen, Bin Zhang","doi":"10.2298/tsci221008029s","DOIUrl":"https://doi.org/10.2298/tsci221008029s","url":null,"abstract":"As a high energy density hydrogen-rich carrier, ammonia (NH3) is a highly promising carbon-free fuel. The large-scale industrial application of NH3 is limited by its low reactivity and high nitrogen oxide (NOX) emission. In this work, the flame and emission characteristics of ammonia/methane (NH3/CH4) non-premixed combustion were investigated under ultrasonic excitation. An experimental system was designed and built, including non-premixed combustion system, loading ultrasonic system, deflection tomography temperature measurement system and flue gas measurement system. Combustion and measurement experiments at different ultrasonic frequencies and NH3/CH4 blending ratios were carried out. Flame images and flue gas species concentrations under ultrasonic excitation were acquired. The 3D temperature field was reconstructed. The influence of ultrasonic excitation at different frequencies on flame characteristics, flame temperature field and emission characteristics of the combustion process was analysed. The mechanism of NH3/CH4 combustion enhancement and emission reduction was revealed when the flame was excited by ultrasonic waves. Results showed that part of the hydrocarbon fuels was replaced by NH3 to reduce carbon dioxide (CO2) emission. The height and colour of the NH3/CH4 flame were changed and the high-temperature area of the flame gradually expanded as ultrasonic acted on the flame. As ultrasonic frequency increased, the emission concentrations of unburned CH4, unburned NH3 and NO decreased significantly. The flame was excited by ultrasonic waves, which reduced its local equivalent ratio, improved combustion efficiency and suppressed NOX generation.","PeriodicalId":23125,"journal":{"name":"Thermal Science","volume":"1 1","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68249102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1