International Communications in Heat and Mass Transfer最新文献

Numerical simulation of the cooling process of TNT and Composition B explosives

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-16 DOI: 10.1016/j.icheatmasstransfer.2025.108953

Samuel M. Barros , Bruna R. Loiola

The present work numerically investigates the influence of the cooling method on the casting of TNT and Composition B explosives. The first approach uses a heating hood on top of the cylindrically shaped grenade to guide the solidification movement. The second method considers a heating probe inserted into the molten explosive. The numerical simulations were obtained using the enthalpy method in ANSYS Fluent software. The numerical verification was accomplished by comparing it with previously published studies. The results of the simulations for the solidification front and the temperature distribution are discussed. It was found that the solidification process using a heating hood leads to a higher portion of liquid explosive concentrate at the top, which could be an advantage compared to end processes in the middle of the explosive. Solidification using the probe heating method also showed the benefit of continuing melting the region above it while the probe is removed, which can prevent void formation. Finally, the explosive's thermophysical properties directly influence the solidification process's velocity. It was concluded that the cooling method using a heating probe takes a longer time to finish, which must be considered during the design of loading processes using the casting method.

{"title":"Numerical simulation of the cooling process of TNT and Composition B explosives","authors":"Samuel M. Barros , Bruna R. Loiola","doi":"10.1016/j.icheatmasstransfer.2025.108953","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108953","url":null,"abstract":"<div><div>The present work numerically investigates the influence of the cooling method on the casting of TNT and Composition B explosives. The first approach uses a heating hood on top of the cylindrically shaped grenade to guide the solidification movement. The second method considers a heating probe inserted into the molten explosive. The numerical simulations were obtained using the enthalpy method in ANSYS Fluent software. The numerical verification was accomplished by comparing it with previously published studies. The results of the simulations for the solidification front and the temperature distribution are discussed. It was found that the solidification process using a heating hood leads to a higher portion of liquid explosive concentrate at the top, which could be an advantage compared to end processes in the middle of the explosive. Solidification using the probe heating method also showed the benefit of continuing melting the region above it while the probe is removed, which can prevent void formation. Finally, the explosive's thermophysical properties directly influence the solidification process's velocity. It was concluded that the cooling method using a heating probe takes a longer time to finish, which must be considered during the design of loading processes using the casting method.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"164 ","pages":"Article 108953"},"PeriodicalIF":6.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Simulation of condensation process with different fluids in micro and nanochannels to investigate the wall material, curvature of the channel, and electric and magnetic fields using the molecular dynamics approach

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-16 DOI: 10.1016/j.icheatmasstransfer.2025.108951

Zekun Liu , Mengxia Wang , Nafiseh Emami , Soheil Salahshour , Riadh Marzouki

Nowadays, computer simulations are a suitable tool for understanding physical phenomena. This paper examined the condensation process of various fluids in micro/nanochannels (MCs/NCs) using molecular dynamics simulations (MDS). The present study examined the condensation time in MCs and NCs across different base fluid types, atomic materials, the number of atomic curvatures (NAC), and the intensities of electric field (EF) and magnetic field (MF). The results reveal that the time required for phase change (condensation) in the helium (He) fluid-structure was less in MCs (2.91 ns) and NCs (2.72 ns) compared to other samples. Changing the atomic materials of MCs and NCs (copper (Cu), platinum (Pt), and Cu/Pt) showed that Pt reduced the condensation times to 2.62 ns for MCs and 2.58 ns for NCs. To enhance atomic interactions in the simulated MCs and NCs, the NAC was modeled at 1, 2, and 3. Increasing the NAC in MCs and NCs decreased the condensation times from 2.91 ns and 2.72 ns to 2.62 ns and 2.58 ns, respectively. The results indicate that condensation time decreases as NAC increases. Increasing the intensities of EF and MF enhanced a fluid's atomic mobility and kinetic energy (KE). Applying an EF with magnitudes of 0, 1, 2, and 5 V/m increased the condensation times of MCs and NCs from 2.91 ns and 2.72 ns to 3.39 ns and 3.36 ns, respectively. Additionally, changing the intensity of MF altered the phase change times in MCs and NCs to 3.17 ns and 3.15 ns, respectively.

{"title":"Simulation of condensation process with different fluids in micro and nanochannels to investigate the wall material, curvature of the channel, and electric and magnetic fields using the molecular dynamics approach","authors":"Zekun Liu , Mengxia Wang , Nafiseh Emami , Soheil Salahshour , Riadh Marzouki","doi":"10.1016/j.icheatmasstransfer.2025.108951","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108951","url":null,"abstract":"<div><div>Nowadays, computer simulations are a suitable tool for understanding physical phenomena. This paper examined the condensation process of various fluids in micro/nanochannels (MCs/NCs) using molecular dynamics simulations (MDS). The present study examined the condensation time in MCs and NCs across different base fluid types, atomic materials, the number of atomic curvatures (NAC), and the intensities of electric field (EF) and magnetic field (MF). The results reveal that the time required for phase change (condensation) in the helium (He) fluid-structure was less in MCs (2.91 ns) and NCs (2.72 ns) compared to other samples. Changing the atomic materials of MCs and NCs (copper (Cu), platinum (Pt), and Cu/Pt) showed that Pt reduced the condensation times to 2.62 ns for MCs and 2.58 ns for NCs. To enhance atomic interactions in the simulated MCs and NCs, the NAC was modeled at 1, 2, and 3. Increasing the NAC in MCs and NCs decreased the condensation times from 2.91 ns and 2.72 ns to 2.62 ns and 2.58 ns, respectively. The results indicate that condensation time decreases as NAC increases. Increasing the intensities of EF and MF enhanced a fluid's atomic mobility and kinetic energy (KE). Applying an EF with magnitudes of 0, 1, 2, and 5 V/m increased the condensation times of MCs and NCs from 2.91 ns and 2.72 ns to 3.39 ns and 3.36 ns, respectively. Additionally, changing the intensity of MF altered the phase change times in MCs and NCs to 3.17 ns and 3.15 ns, respectively.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"164 ","pages":"Article 108951"},"PeriodicalIF":6.4,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Study on the diffusion characteristics of small hole leakage of high-sulfur natural gas in gathering and transmission pipelines

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-15 DOI: 10.1016/j.icheatmasstransfer.2025.108942

Le Hao , Xiaowei Zhai , Kai Wang

The high‑sulfur natural gas contains hydrogen sulfide, which is extremely corrosive and toxic. Its leakage can cause irreversible environmental consequences. This study establishes a high‑sulfur natural gas pipeline leakage model using the three-dimensional CFD numerical calculation method in FLACS. The influences of multiple factors on the extent of leak spread in high‑sulfur natural gas are analyzed. The results show that hydrogen sulfide content in high‑sulfur natural gas inhibits the gas diffusion range. The diffusion distance for 20 % hydrogen sulfide is 0.87 times that of 2 % hydrogen sulfide, and the diffusion height is reduced to 0.83 times due to its higher average molar mass. Pipeline pressure, leakage orifice diameter, and ambient temperature show positive correlations with diffusion distances in all three spatial dimensions. Ambient wind speed increases the horizontal dispersion but inhibits vertical diffusion. The downwind diffusion distance at 5 m/s wind speed is 1.2403 times that at 0.5 m/s, while the diffusion height is reduced to 0.5882 times.

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引用次数: 0

Flow boiling heat transfer of new refrigerant blends: Experimental data in a microchannel and modelling 新型混合制冷剂的流动沸腾传热：微通道中的实验数据和建模

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-15 DOI: 10.1016/j.icheatmasstransfer.2025.108929

Nicolò Mattiuzzo, Marco Azzolin, Arianna Berto, Stefano Bortolin, Davide Del Col

Mixtures of hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs) are suitable as drop-in substitutes in refrigeration and air conditioning, due to the low global warming potential (GWP) and desired thermodynamic properties. In the present work, the flow boiling heat transfer of four HFOs/HFCs mixtures has been studied inside a 0.96 mm diameter channel. Three of those mixtures, R513A (R1234yf/R134a, 56/44 % by mass, GWP_100-y = 629), R516A (R1234yf/R152a/R134a 77.5/14/8.5 % by mass, GWP_100-y = 131) and R515B (R1234ze(E)/R227ea, 91/9 % by mass, GWP_100-y = 299), are azeotropic mixtures, while the fourth is quasi-azeotropic mixture R450A (R1234ze(E)/R134a, 56/44 % by mass, GWP_100-y = 547, ΔT_GL = 0.63 K at 30 °C). The experimental campaign was conducted using a test section where the flow boiling is promoted by a secondary fluid, at 30 °C mean saturation temperature and mass flux between 300 kg m⁻² s⁻¹ and 600 kg m⁻² s⁻¹. The present data have been compared with the heat transfer coefficient of R134a, in order to assess the suitability of its drop-in substitutes. From the comparison between experimental data and the predictions from some semi-empirical models, a modified method is presented. The new flow boiling heat transfer correlation has been successfully tested with data of propane, propylene, R32 and R1234yf.

{"title":"Flow boiling heat transfer of new refrigerant blends: Experimental data in a microchannel and modelling","authors":"Nicolò Mattiuzzo, Marco Azzolin, Arianna Berto, Stefano Bortolin, Davide Del Col","doi":"10.1016/j.icheatmasstransfer.2025.108929","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108929","url":null,"abstract":"<div><div>Mixtures of hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs) are suitable as drop-in substitutes in refrigeration and air conditioning, due to the low global warming potential (GWP) and desired thermodynamic properties. In the present work, the flow boiling heat transfer of four HFOs/HFCs mixtures has been studied inside a 0.96 mm diameter channel. Three of those mixtures, R513A (R1234yf/R134a, 56/44 % by mass, GWP<sub>100-y</sub> = 629), R516A (R1234yf/R152a/R134a 77.5/14/8.5 % by mass, GWP<sub>100-y</sub> = 131) and R515B (R1234ze(E)/R227ea, 91/9 % by mass, GWP<sub>100-y</sub> = 299), are azeotropic mixtures, while the fourth is quasi-azeotropic mixture R450A (R1234ze(E)/R134a, 56/44 % by mass, GWP<sub>100-y</sub> = 547, <em>ΔT</em><sub><em>GL</em></sub> = 0.63 K at 30 °C). The experimental campaign was conducted using a test section where the flow boiling is promoted by a secondary fluid, at 30 °C mean saturation temperature and mass flux between 300 kg m<sup>−2</sup> s<sup>−1</sup> and 600 kg m<sup>−2</sup> s<sup>−1</sup>. The present data have been compared with the heat transfer coefficient of R134a, in order to assess the suitability of its drop-in substitutes. From the comparison between experimental data and the predictions from some semi-empirical models, a modified method is presented. The new flow boiling heat transfer correlation has been successfully tested with data of propane, propylene, R32 and R1234yf.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"164 ","pages":"Article 108929"},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Drag and heat reduction mechanism on a novel combination of spike and micro porous jet concept in supersonic/hypersonic flows

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-15 DOI: 10.1016/j.icheatmasstransfer.2025.108955

Yu-shan Meng, Zhong-wei Wang, Zan Xie, Wei Huang, Yao-bin Niu, Ya-jie Liang

For blunt forebodies flying at supersonic/hypersonic Mach numbers, spike-based concept is widely adopted for simple implementation and economic among various drag and thermal reduction approaches. In this paper, numerical simulation on a mechanical spike attached to a blunt body with micro porous jet is carried out, and the compressible turbulent three-dimensional Navier-Stokes equations are solved with k-ω (SST) turbulence model to compute the typical flow field. The effectiveness of drag reduction and thermal protection is systematically evaluated across varying jet pressure ratios (PR) at different flight altitudes (H = 1 km, 10 km and 27 km) and freestream Mach numbers (Ma_∞ = 4.09, 4.77 and 5.15). When freestream conditions are taken to correspond to a flight speed of Ma = 6 and at an altitude of 27 km, the novel combination configuration with PR = 0.2 can provide drag and heat reduction effect on the spiked forebody by 61.3 % and 73.7 %, respectively. The physics behind the drag reduction and thermal protection associated with the composite configuration is presented with clarity. It is reported that the aerodynamic drag over the spiked blunt model is decreased with rising mass flow rate, and this performance is qualitatively similar for all Mach numbers. Considering that the total drag force increases continuously at large PR and exceeds that with low PR, this study also portrays the necessity of taking the additional jet drag into consideration while comparing the total drag force for different cases.

{"title":"Drag and heat reduction mechanism on a novel combination of spike and micro porous jet concept in supersonic/hypersonic flows","authors":"Yu-shan Meng, Zhong-wei Wang, Zan Xie, Wei Huang, Yao-bin Niu, Ya-jie Liang","doi":"10.1016/j.icheatmasstransfer.2025.108955","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108955","url":null,"abstract":"<div><div>For blunt forebodies flying at supersonic/hypersonic Mach numbers, spike-based concept is widely adopted for simple implementation and economic among various drag and thermal reduction approaches. In this paper, numerical simulation on a mechanical spike attached to a blunt body with micro porous jet is carried out, and the compressible turbulent three-dimensional Navier-Stokes equations are solved with <em>k</em>-<em>ω</em> (SST) turbulence model to compute the typical flow field. The effectiveness of drag reduction and thermal protection is systematically evaluated across varying jet pressure ratios (<em>PR</em>) at different flight altitudes (<em>H</em> = 1 km, 10 km and 27 km) and freestream Mach numbers (<em>Ma</em><sub><em>∞</em></sub> = 4.09, 4.77 and 5.15). When freestream conditions are taken to correspond to a flight speed of <em>Ma</em> = 6 and at an altitude of 27 km, the novel combination configuration with <em>PR</em> = 0.2 can provide drag and heat reduction effect on the spiked forebody by 61.3 % and 73.7 %, respectively. The physics behind the drag reduction and thermal protection associated with the composite configuration is presented with clarity. It is reported that the aerodynamic drag over the spiked blunt model is decreased with rising mass flow rate, and this performance is qualitatively similar for all Mach numbers. Considering that the total drag force increases continuously at large <em>PR</em> and exceeds that with low <em>PR</em>, this study also portrays the necessity of taking the additional jet drag into consideration while comparing the total drag force for different cases.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"164 ","pages":"Article 108955"},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Performance enhancement of flat plate heat exchangers through baffle integration: Thermal, flow, and entropy analysis

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-15 DOI: 10.1016/j.icheatmasstransfer.2025.108937

M. Nithya , M. Senthil Vel , C. Sivaraj

The Plate Heat Exchangers (PHEs) are of essential integral component in industries in diverse aspects and can handle even the minimal temperature differential. This study builds on previous research in a 500 × 2 MW Thermal Power Plant by introducing novel baffle designs in PHEs for the first time. These baffles were specifically developed to address the intricate geometry and complex flow dynamics of PHEs. Building on our previous work, an in-depth analysis was conducted to assess entropy generation, shear stress distribution, and the impact of these baffles on flow maldistribution and thermal performance, as quantified by the JF factor. The study employs the Realizable k-ε turbulence model with scalable wall functions, using the PISO algorithm for pressure-velocity coupling, with a second-order approximation for momentum transport equations and a first-order for turbulence equations. Results indicate a remarkable boost of 11.5 times thermal performance enhancement compared to conventional model. The wedge type experienced a turbulent kinetic energy (TKE) increase of up to 15 %, while the aerofoil exhibited a decrease of 18 %. Additionally, Witte-Shamsundar efficiency was evaluated and advanced regression models were used to predict the Nusselt number and skin friction coefficient, with Gaussian Process Regression (GPR) emerging as the most reliable model. The findings highlight the aerofoil baffles exhibited stable and consistent performance across multiple parameters unlike wedge baffles, enhancing heat exchanger performance along with effective energy utilization.

板式热交换器（PHE）是各行各业不可或缺的重要组成部分，甚至可以处理最小的温差。本研究以之前在 500 × 2 兆瓦火力发电厂进行的研究为基础，首次在 PHE 中引入了新型挡板设计。这些挡板是专门针对 PHE 的复杂几何形状和复杂流动动力学而开发的。在先前工作的基础上，我们进行了深入分析，以评估熵的产生、剪应力的分布以及这些挡板对流动分布不均和热性能的影响，并通过 JF 因子进行量化。研究采用了具有可扩展壁面函数的可实现 k-ε 湍流模型，使用 PISO 算法进行压力-速度耦合，动量传输方程采用二阶近似，湍流方程采用一阶近似。结果表明，与传统模型相比，热性能显著提高了 11.5 倍。楔形模型的湍流动能（TKE）增加了 15%，而气膜模型则减少了 18%。此外，还对 Witte-Shamsundar 效率进行了评估，并使用高级回归模型预测了努塞尔特数和表皮摩擦系数，其中高斯过程回归 (GPR) 是最可靠的模型。研究结果表明，与楔形挡板不同，气膜挡板在多个参数上表现出稳定一致的性能，在提高热交换器性能的同时还能有效利用能源。

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引用次数: 0

Efficient flow boiling in wedge-shaped manifold microchannels for high heat flux chips cooling

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-15 DOI: 10.1016/j.icheatmasstransfer.2025.108964

Xinyu Ji, Yuantong Zhang, Xiaoping Yang, Chuansheng Su, Jinjia Wei

The flow boiling experiments are conducted using HFE-7100 as coolant to comprehensively investigate flow patterns, hydraulic characteristics and heat transfer performance in manifold microchannels with conventional manifolds (CMMC) and wedge-shaped manifolds (WMMC). The wedge-shaped manifolds microchannels demonstrates superior performance by facilitating flow pattern transition from churn flow to annular flow, significantly improving vapor distribution uniformity along the outlet manifold, and enhancing vapor discharge efficiency. Benefiting from these advantages, wedge-shaped manifold microchannels combine lower flow pressure drop, higher boiling heat transfer coefficient and greater critical heat flux. Compared to CMMC, the pressure drops of WMMC are reduced by 17.4 % - 29 %, the heat transfer coefficients are increased by 12.4 % - 37.3 %, and the critical heat fluxes are increased by 11.6 % - 28 %. However, both manifold configurations experience flow instability due to intermittent dry-out on the microchannel walls at high heat fluxes. In WMMC, both flow pattern transitions and flow instability trigger volumetric flow rate oscillations, which can be effectively mitigated by reducing inlet subcooling. These findings provide valuable insights for optimizing two-phase manifold microchannel in applications.

{"title":"Efficient flow boiling in wedge-shaped manifold microchannels for high heat flux chips cooling","authors":"Xinyu Ji, Yuantong Zhang, Xiaoping Yang, Chuansheng Su, Jinjia Wei","doi":"10.1016/j.icheatmasstransfer.2025.108964","DOIUrl":"10.1016/j.icheatmasstransfer.2025.108964","url":null,"abstract":"<div><div>The flow boiling experiments are conducted using HFE-7100 as coolant to comprehensively investigate flow patterns, hydraulic characteristics and heat transfer performance in manifold microchannels with conventional manifolds (CMMC) and wedge-shaped manifolds (WMMC). The wedge-shaped manifolds microchannels demonstrates superior performance by facilitating flow pattern transition from churn flow to annular flow, significantly improving vapor distribution uniformity along the outlet manifold, and enhancing vapor discharge efficiency. Benefiting from these advantages, wedge-shaped manifold microchannels combine lower flow pressure drop, higher boiling heat transfer coefficient and greater critical heat flux. Compared to CMMC, the pressure drops of WMMC are reduced by 17.4 % - 29 %, the heat transfer coefficients are increased by 12.4 % - 37.3 %, and the critical heat fluxes are increased by 11.6 % - 28 %. However, both manifold configurations experience flow instability due to intermittent dry-out on the microchannel walls at high heat fluxes. In WMMC, both flow pattern transitions and flow instability trigger volumetric flow rate oscillations, which can be effectively mitigated by reducing inlet subcooling. These findings provide valuable insights for optimizing two-phase manifold microchannel in applications.</div></div>","PeriodicalId":332,"journal":{"name":"International Communications in Heat and Mass Transfer","volume":"164 ","pages":"Article 108964"},"PeriodicalIF":6.4,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143834024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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

Investigating the use of nano-enhanced phase change material in floor heating system: A numerical approach 研究纳米增强相变材料在地板采暖系统中的应用：数值方法

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-15 DOI: 10.1016/j.icheatmasstransfer.2025.108962

Mohammad Kamrava , Mohammad Ali Fazilati , Davood Toghraie

By increasing the environmental concerns and the scarcity of fossil fuel resources, it is imperative to explore new ways for curbing energy consumption. Among the pivotal strategies aimed at mitigating thermal energy consumption, the utilization of phase change materials (PCMs) stands out prominently. In this study, we delve into the intricacies of floor heating systems and study the effects of incorporating nano-enhanced PCM (NEPCM) on the performance of the system. The work investigates the dynamic behavior of the floor heating system and the temporal characteristics with and without implementing PCM. Al₂O₃, ZnO and CuO are the employed nanoparticles (NPs) whose effect is examined at volume percentages of 1 % and 3 %. The results show that the NP employment reduced the melting start time by 23 % for all employed NP types; also, the time of complete melted state, increased approximately by 369.11 min, followed by a discharge period increment of 454.55 min. By increasing the NP concentration from 1 to 3 %, there was a noticeable reduction for the time of the complete melting; also, the thermal response time of the floor heating decreased by 2 % which was attributed to the elevated thermal conductivity of the PCM.

随着人们对环境问题的日益关注和化石燃料资源的日益匮乏，当务之急是探索抑制能源消耗的新方法。在旨在减少热能消耗的关键战略中，相变材料（PCM）的利用尤为突出。在本研究中，我们深入探讨了地板采暖系统的复杂性，并研究了加入纳米增强型 PCM（NEPCM）对系统性能的影响。这项工作研究了地暖系统的动态行为，以及采用和不采用 PCM 时的时间特性。使用了 Al2O3、ZnO 和 CuO 作为纳米粒子 (NP)，并以 1% 和 3% 的体积百分比对其效果进行了研究。结果表明，在所有采用的 NP 类型中，采用 NP 缩短了 23% 的熔化开始时间；此外，完全熔化状态的时间大约增加了 369.11 分钟，随后放电时间增加了 454.55 分钟。将 NP 浓度从 1% 增加到 3%，完全熔化的时间明显缩短；此外，地板采暖的热响应时间缩短了 2%，这归因于 PCM 的热传导率提高了。

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引用次数: 0

Prediction of 2D film cooling effectiveness distribution: A generative neural network with physical prior knowledge

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-14 DOI: 10.1016/j.icheatmasstransfer.2025.108956

Hao-nan Yan , Cun-liang Liu , Lin Ye , Han-Qing Liu , Si-wei Su , Li Zhang

Film cooling is an essential thermal protection technology that directly influences the performance of hot-end components. Its effectiveness affects combustion efficiency and significantly influences pollutant and carbon emissions during combustion. Consequently, the rapid design and evaluation of cooling schemes have become critical research priorities. Traditional neural network prediction models, however, demand large datasets, with data acquisition costs often being high. This study integrates physically meaningful prior knowledge with image encoding and decoding modules that utilize multi-head attention mechanisms. The goal is to enhance the prediction accuracy of the two-dimensional distribution of film cooling effectiveness (

η

) with limited sample sizes. Furthermore, a highly reliable PSP measurement system was developed to substitute for sample sets generated by CFD simulations. The results indicate that, compared to the traditional model with prediction errors for

η

and non-uniformity (

σ

) exceeding 50 %, the proposed model can control the prediction accuracy within the range of 5 % to 15 %. Furthermore, the integration of encoding and decoding modules with a multi-head attention mechanism allows the model to excel in predicting local distributions while also improving its generalization ability. The gradient-based sensitivity analysis on the input structural parameters revealed that three factors—spacing P, exit width, and inlet-to-outlet area ratio—exhibit more pronounced effects on

η

.

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引用次数: 0

Impact of fractional derivative on the distribution of concentration injected from the walls in diverging channel

IF 6.4 2区工程技术 Q1 MECHANICS

International Communications in Heat and Mass Transfer

Pub Date : 2025-04-14 DOI: 10.1016/j.icheatmasstransfer.2025.108932

M. Tolami , A. Nazari-Golshan , S.S. Nourazar

This study examines the influence of fractional derivatives on the concentration distribution in the flow of a Newtonian fluid within a divergent channel with wall injection. The governing equations, originally formulated with integer derivatives in the radial direction, were modified using Caputo fractional derivatives. These transformed equations were converted into ordinary differential equations through similarity transformations and solved using the Adaptive Fraction Method (AFM) and numerical techniques. Key parameters, including the Reynolds number (Re), Peclet number (Pe), and fractional derivative orders

β

and

ξ

, were analyzed to assess their effects on flow dynamics and concentration profiles. The results indicate that increasing Re and

β

enhances the dimensionless radial velocity and velocity at the channel center while reducing them near the walls. As Re increases, the dimensionless concentration significantly decreases at the center, showing a minor rise near the walls. A surge in

ξ

causes a slight decrease in concentration across the channel, whereas increasing

Pe

reduces concentration in a localized central region with minimal impact elsewhere. Additionally, higher

ξ

values enhance concentration throughout the channel. These findings provide insights for optimizing fluid systems in mass transfer, heat transfer, and flow control by leveraging fractional derivatives to model non-local and memory effects in fluid flow phenomena.

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引用次数: 0