International Journal of Heat and Technology最新文献_第8页

Influence of Inclination Angles on Convective Heat Transfer in Solar Panels 倾角对太阳能板对流换热的影响

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410403

Yousuf Alhendal, Sara Touzani

{"title":"Influence of Inclination Angles on Convective Heat Transfer in Solar Panels","authors":"Yousuf Alhendal, Sara Touzani","doi":"10.18280/ijht.410403","DOIUrl":"https://doi.org/10.18280/ijht.410403","url":null,"abstract":"This study presents an experimental and numerical investigation into the thermofluid characteristics of airflow over an inclined, heated plate, mimicking a solar panel. The inclination of the plate was systematically adjusted from 0° to 90°, and the heat flux was varied from 1000 to 4000 W/m², with Reynolds number ranging from 63,000 to 650,000. The study employed a second-order finite volume method for discretization and resolution of steady fluid dynamics problems, with simulations conducted using Ansys Fluent software. The k-ε RNG turbulence model was utilized for these simulations. The numerical results, validated against experimental data, were extrapolated to assess the behaviour at a wide range of attack angles and flow rates. Correlations were established between the average Nusselt number and friction coefficient, as functions of Reynolds number and attack angles. It was observed that heat transfer was optimized at lower attack angles. Conversely, higher inclination angles resulted in increased skin friction, thereby reducing airflow and negatively impacting heat convection. For larger Reynolds numbers, convective flow enhanced and the resistance of the plate was found to be lower at smaller attack angles. These findings have significant implications for the improvement of solar panel efficiency, offering valuable insights into the optimal configuration for maximizing convective heat transfer.","PeriodicalId":13995,"journal":{"name":"International Journal of Heat and Technology","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136035986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Evaluating Heat Release Rate in Oenological Fermentation: An Innovative Methodology 评价葡萄酒发酵过程中的热释放率:一种创新的方法

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410402

Matteo Malavasi, Luca Cattani, Alessandro Benelli, Luca Pagliarini, Fabio Bozzoli

{"title":"Evaluating Heat Release Rate in Oenological Fermentation: An Innovative Methodology","authors":"Matteo Malavasi, Luca Cattani, Alessandro Benelli, Luca Pagliarini, Fabio Bozzoli","doi":"10.18280/ijht.410402","DOIUrl":"https://doi.org/10.18280/ijht.410402","url":null,"abstract":"The food industry consumes a substantial amount of energy with a large portion dedicated to product heat treatments. Thus, enhancing the efficiency of thermal operations could significantly decrease energy demand, reduce costs, and mitigate pollution in this sector. This is particularly applicable in vinification, where the grape must's temperature is crucial to the final wine quality. In this process, the energy required for fermentative thermostating constitutes a majority of the total energy expenditure. Furthermore, the thermal management of fermenting grape must is influenced by the heat released during the fermentation process. Therefore, understanding the precise distribution of heat release during fermentation could considerably improve the energy efficiency of this production. This study proposes and validates a methodology to achieve this objective. The approach is based on the inverse problem technique, which utilizes temperature measurements of the fermenting product. The validation of this technique shows promising results, indicating the potential applicability of our proposed method.","PeriodicalId":13995,"journal":{"name":"International Journal of Heat and Technology","volume":"104 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136035985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermal Performance Optimization of Perforated Fins for Flat Plate Heat Sinks Using CFD Approach 基于CFD方法的平板散热器穿孔翅片热性能优化

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410426

Nizar F.O. Al-Muhsen, Osamah R.S. Al-Khafaji, Firas Basim Ismail

引用次数: 0

A Comprehensive Numerical Analysis of Natural Convection in Nanofluids within Various Enclosure Geometries: A Review 纳米流体中自然对流的综合数值分析:综述

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410420

Sara Mohammed Abbas, Ahmed Kadhim Hussein

引用次数: 0

Comparative Analysis of Longitudinal Vortex Generators and Louvered Fins in Enhancing Thermal Performance in Compact Heat Exchangers 纵向涡发生器与百叶翅片增强紧凑型换热器热性能的对比分析

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410414

Alvaro Valencia, Sebastian Muñoz

{"title":"Comparative Analysis of Longitudinal Vortex Generators and Louvered Fins in Enhancing Thermal Performance in Compact Heat Exchangers","authors":"Alvaro Valencia, Sebastian Muñoz","doi":"10.18280/ijht.410414","DOIUrl":"https://doi.org/10.18280/ijht.410414","url":null,"abstract":"Compact heat exchangers equipped with flat tubes have traditionally been employed in automotive cooling systems. To augment thermal performance, louvered fins have been integrated on the air side. over recent decades, the efficacy of longitudinal vortex generators (LVG) in heat exchangers has been rigorously investigated, leading to the proposal of innovative designs characterized by their aerodynamic properties. In this study, a novel LVG design sourced from extant literature was juxtaposed against the conventional louvered fins. The shear-stress transport (SST) k-ω model was utilized to depict the turbulence. When the turbulent flow and heat transfer properties were assessed, distinct variations were observed between multiple rows of LVG and the louvered fins. Enhanced thermal performance, with a value reaching 1.3, was noted for configurations incorporating five rows of LVG arrangements at a Reynolds number of 8000. In contrast, the thermal performance of louvered fins was observed to wane with increasing Reynolds numbers, recording a performance measure of merely 1.08 at the aforementioned Reynolds number.","PeriodicalId":13995,"journal":{"name":"International Journal of Heat and Technology","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136034848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Investigation of Thermal Conductivity and Wear Resistance in Bio-Inspired Pitted Pistons for Enhanced Performance in Drilling Mud Pumps 提高钻井泥浆泵性能的仿生凹坑活塞的导热性和耐磨性研究

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410422

Xuejing Cheng, Qian Cong

{"title":"Investigation of Thermal Conductivity and Wear Resistance in Bio-Inspired Pitted Pistons for Enhanced Performance in Drilling Mud Pumps","authors":"Xuejing Cheng, Qian Cong","doi":"10.18280/ijht.410422","DOIUrl":"https://doi.org/10.18280/ijht.410422","url":null,"abstract":"In the demanding environment of drilling mud pumps, failures attributed to piston wear constitute approximately 80% of malfunctioning incidents. While enhanced structural designs and superior materials have been employed, enduring challenges remain. A potential solution identified in previous works is surface texturing, specifically the optimization of pit structures on piston rings, with promising outcomes in friction reduction. Yet, the vital role of thermal parameters in high-intensity environments like mud pumps has been largely overlooked. In this study, the dung beetle's irregular pit structure, known for friction reduction by minimizing soil contact, is utilized as a biological model. The impact of pit geometry, including diameter, angle, and depth, on thermal conductivity, heat transfer, cooling, and heat dissipation has been thoroughly investigated. Preliminary analyses were conducted to gauge the effects of pit diameter on thermal conductivity and piston lifespan. Subsequent analyses were focused on the influence of pit angle in determining thermal gradients across the piston, and its effect on durability. Further investigation was performed to assess the implications of pit depth on heat dissipation and piston longevity. Utilizing Ansys software, the thermal and wear resistance mechanisms of the pitted piston were examined, revealing an enhancement in lifespan by up to 40.60% in comparison to non-pitted counterparts. These findings contribute to the broader comprehension of the interplay between surface texture, thermal performance, and wear resistance, heralding new avenues for thermal management in diverse mechanical machinery. The presented study lays a foundational framework for further research and represents a significant advancement towards a new generation of thermally efficient, wear-resistant mechanical components inspired by nature's perfected mechanisms.","PeriodicalId":13995,"journal":{"name":"International Journal of Heat and Technology","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136034860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Convective Heat Transfer of Radiating Magneto-Micropolar Nanofluid Flow 辐射磁微极纳米流体流动的对流换热

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410418

Sheetal Gonsalves, Swapna Gabbur

{"title":"Convective Heat Transfer of Radiating Magneto-Micropolar Nanofluid Flow","authors":"Sheetal Gonsalves, Swapna Gabbur","doi":"10.18280/ijht.410418","DOIUrl":"https://doi.org/10.18280/ijht.410418","url":null,"abstract":"This work presents an in-depth examination of heat and mass transfer phenomena in a radiative and chemically reactive magneto-micropolar nanofluid flow under the influence of convective boundary conditions. The governing equations of the model, represented in their non-linear form via Falkner and Skan transformations, are scrutinized using the Finite Element Method (FEM). Validation with existing literature corroborates the precision of the proposed model. Analyses of the results elucidate the impacts of various parameters on the temperature, species concentration, micro-rotation, and velocity characteristics of the system. Notably, an enhancement in the thermal conductivity of the magneto-micropolar nanofluid is observed in correlation with an increased nanoparticles volume fraction. A positive relationship is discerned between the temperature and the parameters for radiation and convective boundary conditions. Furthermore, a decrement in the Schmidt number is associated with an accelerated diffusion rate. The findings derived from this study hold substantial implications for practical applications in diverse fields such as heat and cooling systems, enhanced oil recovery, thermal management in electronics, material processing, and nanofluidics. This research thus contributes to the existing body of knowledge by offering an intricate understanding of the behavior and manipulation of magneto-micropolar nanofluid flow.","PeriodicalId":13995,"journal":{"name":"International Journal of Heat and Technology","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136034873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An Examination of Heat Transfer Dynamics in Pulsating Air Flow within Pipes: Implications for Automotive Exhaust Engines 管道内脉动气流的传热动力学研究:对汽车排气发动机的启示

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410404

Yuki Kato, Guanming Guo, Masaya Kamigaki, Kamigaki Fujimoto, Mikimasa Kawaguchi, Keiya Nishida, Masanobu Koutoku, Hitoshi Hongou, Haruna Yanagida, Yoichi Ogata

{"title":"An Examination of Heat Transfer Dynamics in Pulsating Air Flow within Pipes: Implications for Automotive Exhaust Engines","authors":"Yuki Kato, Guanming Guo, Masaya Kamigaki, Kamigaki Fujimoto, Mikimasa Kawaguchi, Keiya Nishida, Masanobu Koutoku, Hitoshi Hongou, Haruna Yanagida, Yoichi Ogata","doi":"10.18280/ijht.410404","DOIUrl":"https://doi.org/10.18280/ijht.410404","url":null,"abstract":"The detailed understanding of heat transfer in the pulsating airflow in the pipe is critical to reducing heat losses in the engine exhaust stream and improving catalyst performance. In the present investigation, we have scrutinized the impact of pulsation frequencies ranging from 0-90 Hz on the flow velocity field and the consequent heat transfer through a horizontal pipe wall. The Nusselt numbers were evaluated at three distinct cross-sectional points moving from upstream to downstream, by systematically modulating the frequency. Temporal variations in the velocity field and temperature were captured utilizing particle image velocimetry (PIV) and dual-thermocouple probes, respectively. Intriguingly, while the Nusselt number for steady flow at 0 Hz closely adhered to Gnielinski’s equation, the pulsating flow demonstrated a peak between 25-35 Hz, a pattern not predicted by the prevailing quasi-steady-state theory. The observed frequency response of turbulence was found to be congruous with the Nusselt number, indicating that the heightened heat transfer at frequencies of 25-35 Hz could be attributed to the enhanced turbulence and the temperature gradient between the fluid and the wall surface during the deceleration phase in the hysteresis of turbulence in the pulsating flow. The unique frequency characteristics of heat transfer that were uncovered in this study, with respect to both flow velocity and temperature, offer valuable insights for devising strategies to mitigate heat loss during ignition and idling. Furthermore, these findings provide robust benchmarks for validating numerical simulations of pulsating flows in real-life automotive engines.","PeriodicalId":13995,"journal":{"name":"International Journal of Heat and Technology","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136035987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Effects of Repeated Heat Treatments on the Wear Resistance of Pre-Carburized Steel 反复热处理对预渗碳钢耐磨性的影响

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410429

Jamal Nayief Sultan, Emad Toma Karash, Mohammad Takey Elias Kassim, Adel M. Ali, Hssein A. Ibrhim

引用次数: 0

Evaluating the Performance and Exhaust Emissions of a Micro Gas Turbine Engine Fueled by Kerosene and Olive Oil Methyl Ester Blends 以煤油和橄榄油甲酯混合物为燃料的微型燃气涡轮发动机性能和废气排放评估

International Journal of Heat and Technology Pub Date : 2023-08-31 DOI: 10.18280/ijht.410427

Abdulsattar J. Hasan, Suhad A. Rasheed

{"title":"Evaluating the Performance and Exhaust Emissions of a Micro Gas Turbine Engine Fueled by Kerosene and Olive Oil Methyl Ester Blends","authors":"Abdulsattar J. Hasan, Suhad A. Rasheed","doi":"10.18280/ijht.410427","DOIUrl":"https://doi.org/10.18280/ijht.410427","url":null,"abstract":"The search for renewable, affordable energy alternatives has gained momentum in light of dwindling fossil fuel reserves. Biofuels, particularly those derived from plant sources, present a viable solution to both the energy crisis and environmental degradation. This study focuses on the implementation of olive oil methyl ester (OME) biofuel in micro gas turbine engines. Biofuel blends, with volumetric OME concentrations ranging from 20% to 80% in standard kerosene, were prepared and tested on a GT 85-2-H micro gas turbine unit. The engine's performance and exhaust emissions were evaluated under two different operational parameters: constant speed and constant load. The use of an 80% OME biofuel blend resulted in an 8.7% reduction in overall efficiency and a 13.1% increase in specific fuel consumption (SFC) under an 80% load. However, it also led to a significant improvement in exhaust emissions, with reductions of 28.8%, 39%, and 33.8% recorded for carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NO x ), respectively. Similarly, under a constant speed test at 20000 rpm, an 80% OME blend caused a 10.5% reduction in overall efficiency and a 13.6% increase in SFC. Nevertheless, the same blend improved the CO, HC, and NO x emissions by 38%, 41.4%, and 36%, respectively. The findings confirm the potential of OME as a biofuel in micro gas turbine engines, underlining its effectiveness in reducing harmful emissions. This research emphasizes the feasibility of biofuels derived from olive oil in addressing future energy demands while mitigating environmental impact.","PeriodicalId":13995,"journal":{"name":"International Journal of Heat and Technology","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136034847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0