Case Studies in Thermal Engineering最新文献_第5页

Response surface methodology and sensitivity analysis of RP fluid model over curved stretching sheet: Non-similar investigation

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-20 DOI: 10.1016/j.csite.2025.105884

Mohammed Aldandani , Ahmed Jan

{"title":"Response surface methodology and sensitivity analysis of RP fluid model over curved stretching sheet: Non-similar investigation","authors":"Mohammed Aldandani , Ahmed Jan","doi":"10.1016/j.csite.2025.105884","DOIUrl":"10.1016/j.csite.2025.105884","url":null,"abstract":"<div><div>The transport performance for a convective non-Newtonian fluid model with heat transfer can be measured through skin friction coefficient, and Nusselt number. The aim of this study is to examine the sensitivity analysis of heat transfer and drag forces effects on magnetized Reiner-Philippoff fluid model over curved surface. The equations that regulate the flow issue are converted into a set of nonlinear dimensionless partial differential equations via a non-similarity transformation. These equations are treated as ordinary differential equations by employing the local non-similarity method up to second level truncation and simulated using MATLAB routine bvp4c. Prior to doing the sensitivity analysis of skin friction coefficient, and Nusselt number, we use response surface methods to construct empirical connections for these parameters. The empirical relations' quality of fit is determined using the analysis of variance table's coefficient of determination. The results show that coefficient of determination for skin friction coefficient, and Nusselt number are 100 %, 99.99 % and 97.73 % respectively. This means that we have obtained best fitted empirical relations. The results of sensitivity analysis disclosed that skin friction coefficient is most sensitive to Reiner-Philippoff fluid parameter.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105884"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480619","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}

引用次数: 0

Optimization of a cylindrical heatsink with L-shaped fins to minimize thermal resistance variation by installation angle

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-20 DOI: 10.1016/j.csite.2025.105860

Gihyun Song, Hak-Ho Nam, Seungmin Heo, Se-Jin Yook

{"title":"Optimization of a cylindrical heatsink with L-shaped fins to minimize thermal resistance variation by installation angle","authors":"Gihyun Song, Hak-Ho Nam, Seungmin Heo, Se-Jin Yook","doi":"10.1016/j.csite.2025.105860","DOIUrl":"10.1016/j.csite.2025.105860","url":null,"abstract":"<div><div>Light Emitting Diode (LED) lighting can be installed at various angles depending on user preferences. However, the cooling performance of heatsinks may decrease with changes in installation angle, potentially affecting the lifespan of LED lighting. This study considered L-shaped fins on a cylindrical base in an effort to minimize variations in thermal resistance with changes in installation angle while reducing the heatsink mass. Thermal resistance was analyzed based on the area removed from rectangular fins to form L-shaped fins. The heatsink's thermal resistance was predicted across a range of installation angles through numerical analysis using ANSYS FLUENT, and the accuracy of these predictions was validated experimentally. By varying the fin deletion area, fin count, and cylindrical base radius, the ranges of porosity factor and finning factor were determined as 0.7054 ≤ <em>φ</em> ≤ 0.7494 and 2.1069 ≤ <em>ψ</em> ≤ 3.9874, respectively. With the heatsink installation angle varying from 0° to 180°, the rate of change in thermal resistance for a cylindrical heatsink with rectangular fins (without a deletion area) was large, reaching 24 %, while that for a cylindrical heatsink with L-shaped fins was significantly reduced, staying within 10 %. A correlation equation to estimate the thermal resistance of an L-finned cylindrical heatsink was proposed, predicting thermal resistance with an error margin of up to 15 %. The cylindrical heatsink with L-shaped fins developed in this study is expected to be applicable in various LED lighting systems requiring both reduced heatsink mass and minimal thermal resistance variation with changes in installation angle.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105860"},"PeriodicalIF":6.4,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453458","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}

引用次数: 0

An experimental study on the effect of lobe swirl device and its transition parts on thermal performance using Graphene-CuO/water nanohybrid

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105925

Farag A. Diabis , Abd Rahim Abu Talib , Norkhairunnisa Mazlan , Eris Elianddy Supeni

{"title":"An experimental study on the effect of lobe swirl device and its transition parts on thermal performance using Graphene-CuO/water nanohybrid","authors":"Farag A. Diabis , Abd Rahim Abu Talib , Norkhairunnisa Mazlan , Eris Elianddy Supeni","doi":"10.1016/j.csite.2025.105925","DOIUrl":"10.1016/j.csite.2025.105925","url":null,"abstract":"<div><div>Enhancing heat transfer efficiency is a key focus in thermal applications. Smooth channels often suffer from poor fluid mixing, limiting their performance. Swirl flow techniques have been introduced to improve heat exchanger efficiency by altering flow direction and inducing turbulence. However, integrating nanofluids with swirl techniques presents challenges such as increased pressure loss and nanoparticle sedimentation. The four-lobed swirl generator is a promising solution, delivering high swirl intensity with manageable pressure loss. This study explores the impact of GO-CuO/water hybrid nanofluid and Reynolds numbers on the thermal performance of a four-lobed swirl generator. The system parameters include a twisted angle (θ = 360°), β-transition type, transition multiplier (n = 0.5 mm), and a variable helix (t = 1). The hybrid nanofluid, synthesized with a 20 % GO to 80 % CuO ratio, has volume concentrations of 0.15%–0.75 % wt., with Reynolds numbers from 15,000 to 35,000. Results indicate a significant heat transfer enhancement (1.26–1.72 times) with a moderate friction factor increase (1.27–1.53). The highest thermal performance (1.511) occurs at 0.75 % nanofluid concentration and <em>Re</em> = 25,000. This study confirms the four-lobed swirl generator's effectiveness in improving heat exchanger efficiency while maintaining an acceptable pressure drop.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105925"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463998","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}

引用次数: 0

Influence of nitrogen contents in fuel and oxidizer on nitrogen oxide emissions during NG/O2 combustion

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105868

Wontak Choi , Seunggi Choi , Yonmo Sung

{"title":"Influence of nitrogen contents in fuel and oxidizer on nitrogen oxide emissions during NG/O2 combustion","authors":"Wontak Choi , Seunggi Choi , Yonmo Sung","doi":"10.1016/j.csite.2025.105868","DOIUrl":"10.1016/j.csite.2025.105868","url":null,"abstract":"<div><div>This study aims to understand the NO<sub>x</sub> emission characteristics during pure oxygen (O<sub>2</sub>) combustion of natural gas (NG) and to provide design data for application in forging furnaces. We numerically investigated the sensitivity of NO<sub>x</sub> emissions to an up to 10 % increase in nitrogen (N<sub>2</sub>) content of the fuel and oxidizer. According to the impact analysis, the two cases have a more adverse effect on NO<sub>x</sub> emissions. The numerical model established in this study was verified using experimental results obtained by the International Flame Research Foundation (IFRF). In addition, the N<sub>2</sub> content of the fuel was fixed and the impact of NO<sub>x</sub> emissions on the O<sub>2</sub> ratio (O<sub>2</sub>/fuel equivalence ratio) was investigated. The calculated results for the temperature field, velocity field, and NOx concentration at the furnace outlet agree with the IFRF experimental results. As the N<sub>2</sub> content in the oxidizer and fuel increased, the NO<sub>x</sub> concentration also increased. NO<sub>x</sub> emissions were much higher with a larger amount of N<sub>2</sub> in the fuel than in the oxidizer. With fixed N<sub>2</sub> content in the fuel, NO<sub>x</sub> concentration tended to increase as the O<sub>2</sub> ratio increased. As the N<sub>2</sub> content in the fuel increased, the tendency of the NO<sub>x</sub> concentration to increase with the O<sub>2</sub> ratio became more evident. This study emphasizes the importance of minimizing the N<sub>2</sub> content in both the fuel and oxidizer during NG-O<sub>2</sub> combustion, and suggests that NO<sub>x</sub> emissions can be effectively controlled by adjusting the oxygen ratio when N<sub>2</sub> is present.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105868"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471333","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}

引用次数: 0

Low-temperature combustion analysis of butanol isomer/diesel blends under reduced oxygen conditions in a constant volume combustion chamber

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105929

Jinlin Han , L.M.T. Somers

{"title":"Low-temperature combustion analysis of butanol isomer/diesel blends under reduced oxygen conditions in a constant volume combustion chamber","authors":"Jinlin Han , L.M.T. Somers","doi":"10.1016/j.csite.2025.105929","DOIUrl":"10.1016/j.csite.2025.105929","url":null,"abstract":"<div><div>Butanol is an attractive biofuel and power resource in the field of power generation, long-haul heavy-duty transportation, and off-road applications. Particularly, when combined with low temperature combustion concepts, the NOx/soot tradeoff can be relieved at the presence of exhaust gas recirculation. Therefore, the combustion and ignition characteristics of butanol isomers at low oxygen (O2) availability should be fully understood. This work focuses on the low temperature heat release and negative temperature coefficient behaviors at low O2% in a CVCC. Three butanol isomers are blended with diesel from 20 to 80 vol% and tested at various temperatures and oxygen concentrations (17 %, 15 %, 13 %). Tert-butanol/diesel blends yield the shortest ignition delay (ID) time. This is likely due to the competition of the OH radical between the butanol and alkane. The results also show ID increases as the blend ratio increases. Specifically, at a low blend ratio, the ignition delay will increase as the oxygen concentration and chamber temperature decrease. As the blend ratio reaches 60 and 80 vol %, ID decreases at low chamber temperature irrespective of the O2%, due to early low temperature heat release. A similar transition trend can be found in the burn duration results as well.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105929"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453465","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}

引用次数: 0

Exploration of physical characteristics of gyrotactic microorganisms and Cattaneo-Christov heat flux past a cone and a wedge with thermal radiation

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105916

G. Dharmaiah , K.S. Balamurugan , H. Saxena , U. Fernandez-Gamiz , S. Noeiaghdam , Maddina Dinesh Kumar , C.S.K. Raju

引用次数: 0

Artificial intelligence aided microwave coagulation therapy: Analysis of heat transfer to tumor tissue via hybrid modeling

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105927

Zheng Yang , KeWei Dai , Wujun Zhang , Rui Zhou , QingBin Wu , Liang Liu , HuaiRong Qu

{"title":"Artificial intelligence aided microwave coagulation therapy: Analysis of heat transfer to tumor tissue via hybrid modeling","authors":"Zheng Yang , KeWei Dai , Wujun Zhang , Rui Zhou , QingBin Wu , Liang Liu , HuaiRong Qu","doi":"10.1016/j.csite.2025.105927","DOIUrl":"10.1016/j.csite.2025.105927","url":null,"abstract":"<div><div>This study investigates the application of three regression models including Decision Tree (DT), Light Gradient Boosting Machine (LGBM), and Random Forest (RF) to predict temperature distribution in a tumor tissue based on two inputs, r(m) and z(m), using a dataset comprising over 64,000 records. Temperature distribution near the tumor tissue was calculated using numerical simulation of heat transfer which constituted electromagnetic and bioheat transfer models. The simulations were carried out for cancer treatment via hyperthermia utilizing antenna for electromagnetic heating. Machine learning models were trained in combination with computational heat transfer to obtain temperature distribution. We employed Massively Parallel Hyperparameter Tuning (MPPT) to optimize the hyperparameters for each model, ensuring optimal performance. Obtaining a score of 0.9991 by R<sup>2</sup> criterion (Coefficient of Determination), an MSE (Mean Squared Error) of 0.1526, and an MAE (Mean Absolute Error) of 0.2545, the results show that the LGBM is the best-fit model. With R<sup>2</sup> = 0.9981, MSE = 0.3039, and MAE = 0.2744, the Random Forest model was likewise quite effective. The Decision Tree model still performed adequately, but it was not as effective as the other options (R<sup>2</sup> = 0.9923, MSE = 1.2868, MAE = 0.6138). Hyperparameter tuning is crucial for obtaining better model performance, and these results show that LGBM works well for regression tasks on big datasets. The results indicated that machine learning is a robust technique in evaluation of cancer therapy efficiency via hyperthermia method by determination of temperature distribution in the tumor tissue.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105927"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520439","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}

引用次数: 0

Research on the oscillating flow and heat transfer of the cooling gallery inside a multi-material composite piston

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-19 DOI: 10.1016/j.csite.2025.105879

Haixiang Yang , Jilin Lei , Chunming Wang , Fanghao Sun , Xiwen Deng , Jun Wen , Xiangsen Jiang

{"title":"Research on the oscillating flow and heat transfer of the cooling gallery inside a multi-material composite piston","authors":"Haixiang Yang , Jilin Lei , Chunming Wang , Fanghao Sun , Xiwen Deng , Jun Wen , Xiangsen Jiang","doi":"10.1016/j.csite.2025.105879","DOIUrl":"10.1016/j.csite.2025.105879","url":null,"abstract":"<div><div>The heat transfer ability of cooling gallery inside high-strengthened diesel engine composite piston is highly required. This article established an oscillating heat transfer model for gas-liquid two-phase flow of cooling gallery. Simulated experiments were conducted to calibrate the model. The effects of two oil supply options and different supply rates on the heat transfer characteristics were studied. The results indicate that injection option has a better cooling performance, violent oscillating flow happens in both the outer gallery and the inner cavity. The oil charge ratio (OCR) of injection option schemes stabilizes at about 50 %, and it takes 35–50 cycles to reach stability. VA8 (oil supply rate is 27.6 L/min) has the best cooling effect, its highest temperature is 445.8 °C at the rim of combustion bowl. However, pumping option is not suitable for the piston in this study and similar diesel engines. The oscillating effect is not significant, both low and high oil supply rates lead to a nearly full-filled cooling gallery. Moreover, it takes more than 150 cycles to reach stability. VB4 (oil supply rate is 6.8 L/min) has the best cooling effect among the pumping option schemes, its highest temperature is 511.4 °C, 10.872 % higher than that of VA8.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105879"},"PeriodicalIF":6.4,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143487523","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}

引用次数: 0

Improve the performance of cold crucible used for emissivity measurement of molten metal

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-18 DOI: 10.1016/j.csite.2025.105898

Gangquan Wang , Yinxue Bai , Baolin Zhao , Longfei Li , Yue Liu , Kaihua Zhang , Yufang Liu , Kun Yu

{"title":"Improve the performance of cold crucible used for emissivity measurement of molten metal","authors":"Gangquan Wang , Yinxue Bai , Baolin Zhao , Longfei Li , Yue Liu , Kaihua Zhang , Yufang Liu , Kun Yu","doi":"10.1016/j.csite.2025.105898","DOIUrl":"10.1016/j.csite.2025.105898","url":null,"abstract":"<div><div>High-purity titanium (Ti) and its alloys are among the most promising materials for advanced turbine blades in aerospace engines. Electromagnetic cold crucible melting is a novel technique for producing contamination-free pure Ti ingots. To enhance the utilization efficiency of electromagnetic energy, an initial assessment of the electromagnetic energy utilization rate of the cold crucible was conducted. Subsequently, based on numerical simulation, the impact of electromagnetic energy on the uniformity of the electromagnetic field within the Ti melt was investigated, providing a theoretical basis for performance optimization. The results indicated that a cylindrical structure with a spherical bottom significantly improves the electromagnetic utilization and temperature uniformity of the crucible. Finally, using the optimized crucible, a measurement apparatus for the spectral emissivity of molten Ti was developed. By simulation and optimization of the optical path system and sample temperature field, high-precision spectral emissivity measurement of molten Ti was achieved. This study underscores the potential of optimized electromagnetic cold crucible technology in advancing the production and precise measurement of high-purity Ti, critical for aerospace applications.</div></div>","PeriodicalId":9658,"journal":{"name":"Case Studies in Thermal Engineering","volume":"68 ","pages":"Article 105898"},"PeriodicalIF":6.4,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463995","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}

引用次数: 0

Effect of operational strategy on thermal response of a model energy diaphragm wall

IF 6.4 2区工程技术

Case Studies in Thermal Engineering Pub Date : 2025-02-18 DOI: 10.1016/j.csite.2025.105889

Chenglong Wang , Pengxi Zhu , Xuanming Ding , Qi Wu , Gangqiang Kong

引用次数: 0