International Journal of Heat and Mass Transfer最新文献_第2页

Role of hypergravity in minichannel flow boiling 超重力在微型通道流沸腾中的作用

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-14 DOI: 10.1016/j.ijheatmasstransfer.2024.126429

Ruixue Yang , Chengcheng Fan , Bo Li , Chengbin Zhang , Yongping Chen

The minichannel boiling in a pumped two-phase fluid loop is an efficient thermal management for modern fighter jets in hypergravity environment. A variable-speed rotating platform is constructed to simulate the hypergravity environment. An experiment of the mechanically pumped two-phase fluid loop is conducted to investigate the flow boiling characteristics of minichannel evaporator under hypergravity conditions, with a focus on the centripetal and centrifugal radial flow modes. In addition, the dynamic heat transfer performance of the evaporator under centrifugal and centripetal flow modes is quantitatively evaluated by the average wall temperature, heat transfer coefficient, critical hypergravity acceleration. The results indicate that, the role of hypergravity in minichannel flow boiling in centripetal flow mode differs from that in the centrifugal flow mode. In the centripetal flow mode, the wall temperature of minichannel evaporator exhibits the "L"-shaped trend with respective to the hyper-gravitational acceleration, suggesting that hyper-gravitational acceleration contributes to heat transfer enhancement. In the centrifugal flow mode, an increase in hyper-gravitational acceleration leads to an overall "V"-shaped trend in the wall temperature of evaporator, indicating that there is optimum boiling performance at an appropriate hyper-gravitational acceleration. In addition, the critical hypergravity acceleration increases as the rise of flow rate in the centrifugal flow mode, no critical hypergravity acceleration is observed in the centripetal flow mode.

泵送两相流体回路中的微型通道沸腾是现代战斗机在超重力环境下的一种高效热管理方法。我们建造了一个变速旋转平台来模拟超重力环境。对机械泵送两相流体回路进行了实验，以研究超重力条件下微型通道蒸发器的流动沸腾特性，重点是向心和离心径向流动模式。此外，还通过平均壁温、传热系数、临界超重力加速度对离心和向心流动模式下蒸发器的动态传热性能进行了定量评估。结果表明，向心流模式下超重力在微型通道流沸腾中的作用不同于离心流模式。在向心流模式下，微型通道蒸发器的壁温随超重力加速度的变化呈 "L "型趋势，这表明超重力加速度对传热有促进作用。在离心流动模式下，超重力加速度的增加导致蒸发器壁温总体呈 "V "形趋势，表明在适当的超重力加速度下沸腾性能最佳。此外，在离心流模式下，临界超重力加速度随着流速的增加而增加，而在向心流模式下则没有观察到临界超重力加速度。

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引用次数: 0

Experimental study on heat transfer enhancement and flow performance of microencapsulated phase change slurry in microchannel with different rib structures 不同肋骨结构微通道中微胶囊相变浆料传热增强和流动性能的实验研究

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-14 DOI: 10.1016/j.ijheatmasstransfer.2024.126437

Chenzhen Liu , Yibin Bao , Baohuan Li , Peizhao Lyu , Xinjian Liu , Zhonghao Rao

Microencapsulated phase change slurry (MPCS), with higher phase change latent heat, promises to be an effective new working fluid for microchannel cold plates. In this study, an experimental platform was established to investigate the heat transfer and flow characteristics of MPCS in microchannel cold plates with different rib structures. The wall temperature, convective heat transfer, and pressure drop characteristics of water and MPCS with different mass concentrations at various inlet temperatures and flow rates in straight rib microchannel structures were investigated and at an inlet temperature of 29 °C, 5 wt% MPCS in straight rib microchannels significantly reduced the overall temperature difference between the wall and the inlet, with the convective heat transfer performance improving by up to 8 % compared to water. And the pressure drop characteristics of MPCS exhibited a regular pattern with temperature variation. Additionally, the heat transfer and flow characteristics of MPCS and water were studied in three different microchannel structures: straight ribs, staggered pin fins, and non-staggered pin fins. The comprehensive performance of 5 wt% MPCS in the staggered pin-fin microchannel improved by up to 26 % compared to the straight rib microchannel. This study provides theoretical insights into the heat transfer and flow characteristics of MPCS in microchannels, offering valuable support for the design of microchannel heat exchangers.

微胶囊相变浆料（MPCS）具有更高的相变潜热，有望成为微通道冷板的一种有效的新型工作流体。本研究建立了一个实验平台，以研究不同肋片结构的微通道冷板中 MPCS 的传热和流动特性。研究了水和不同质量浓度的 MPCS 在不同入口温度和流速下在直肋微通道结构中的壁温、对流传热和压降特性。在入口温度为 29 °C 时，直肋微通道中 5 wt% 的 MPCS 显著降低了壁面和入口之间的整体温差，与水相比，对流传热性能提高了 8%。MPCS 的压降特性随温度的变化呈现出一定的规律。此外，还研究了 MPCS 和水在三种不同微通道结构（直肋、交错针翅和无交错针翅）中的传热和流动特性。与直肋微通道相比，交错针翅微通道中 5 wt% MPCS 的综合性能提高了 26%。这项研究为微通道中 MPCS 的传热和流动特性提供了理论依据，为微通道热交换器的设计提供了宝贵的支持。

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引用次数: 0

Heat transfer performance investigation on two-dimensional aligned GO/EP composites 二维排列的 GO/EP 复合材料的传热性能研究

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-14 DOI: 10.1016/j.ijheatmasstransfer.2024.126427

Long Chen , Chenyang Zhu , Yeqin Shen , Zhanqiang Liu , Qinghua Song

High-altitude aircraft are susceptible to icing due to supercooled droplets, which can compromise flight safety. To address this, a novel approach was taken by leveraging electromagnetic field coupling to synthesize two-dimensional aligned graphene oxide/epoxy resin (GO/EP) composites. The thermal conductivity was significantly enhanced by 5 % over non-aligned GO/EP composites and by 5.7 % over pure EP, thereby improving the efficiency of electric heating de-icing systems. A mathematical heat transfer model was developed for the two-dimensional aligned GO/EP composite, based on the principles of thermal resistance and equivalent thermal conductivity, an optimized effective medium theory heat transfer model for GO/EP was established by introducing the parameter "m", which effectively predicting the thermal conductivity of composites. Both experimental and simulation studies confirmed a notable increase in thermal conductivity. The effective heat transfer path length within the aligned GO/EP composite was calculated to be 41.4 % longer than in the non-aligned version, indicating a more efficient heat conduction pathway. The research demonstrates that the integration of graphene oxide into epoxy resin creates thermally conductive channels, boosting heat transfer efficiency. The alignment of two-dimensional GO channels optimizes thermal conductivity without the need for increased doping, presenting a solution for high thermal conductivity composites in anti-/deicing applications. This innovation is expected to have implications for the future of aircraft de-icing technology.

高空飞机很容易因过冷液滴而结冰，从而危及飞行安全。为解决这一问题，我们采用了一种新方法，即利用电磁场耦合合成二维对齐氧化石墨烯/环氧树脂（GO/EP）复合材料。与未对齐的氧化石墨烯/环氧树脂复合材料相比，其热导率明显提高了 5%，与纯环氧树脂相比提高了 5.7%，从而提高了电加热除冰系统的效率。根据热阻和等效热导率原理，建立了二维对齐 GO/EP 复合材料的数学传热模型，并通过引入参数 "m"，建立了 GO/EP 的优化有效介质理论传热模型，从而有效地预测了复合材料的热导率。实验和模拟研究都证实了热导率的显著提高。经计算，对齐的 GO/EP 复合材料内的有效传热路径长度比未对齐的复合材料长 41.4%，这表明热传导路径更有效。该研究表明，将氧化石墨烯融入环氧树脂可形成导热通道，提高热传导效率。二维氧化石墨烯通道的排列优化了导热性，无需增加掺杂，为防冰/除冰应用中的高导热复合材料提供了一种解决方案。这项创新有望对未来的飞机除冰技术产生影响。

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引用次数: 0

Effect of altitude on heat transfer performance of full-scale metal foam heat exchangers produced by additive manufacturing 海拔高度对增材制造全尺寸金属泡沫热交换器传热性能的影响

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-13 DOI: 10.1016/j.ijheatmasstransfer.2024.126424

Yifan Wang , Xiaoxia Sun , Tingwei Zhang , Chen Ding , Fuifang Kang , Shen Liang , Lili Shen , Xinglong Ma

Increasing altitude negatively impacts heat exchangers efficiency, limiting vehicle power and system performance. To address this, enhancing heat exchangers performance and compactness is crucial. Metal foam, with its high porosity and large specific surface area, is ideal for cooling fins in automotive heat exchangers. This study used laser additive manufacturing with 6061 aluminum powder to fabricate two Kelvin open-cell metal foam heat exchangers: a double-layer (DKHE) and a three-layer (TKHE) structure, both measuring 80 mm × 270 mm × 210 mm. Performance was assessed in a plateau simulation chamber across altitudes from 0 m to 4500 m. Results showed that at a gas flow rate of 1500m³/h at 0 m, the overall heat transfer coefficients for TKHE and DKHE were 1625 W/m²·K and 1301.7 W/m²·K, respectively. At 4500 m, these values dropped by 47.7% and 37.2%, respectively. Pressure drops also decreased by 40% and 39.2%, respectively. The area goodness factor indicated TKHE's superior performance. Additionally, permeability K and inertia coefficient f_i, both increasing with altitude, were 36% and 104% higher for TKHE than DKHE. This research applies additive manufacturing for heat exchangers manufacturing which avoids the degradation of heat exchangers performance due to contact thermal resistance. Addressing the performance data gap for metal foam heat exchangers in plateau regions and laying the foundation for future design improvements.

海拔的升高会对热交换器的效率产生负面影响，从而限制车辆的动力和系统性能。为此，提高热交换器的性能和紧凑性至关重要。金属泡沫具有孔隙率高、比表面积大的特点，是汽车热交换器冷却翅片的理想材料。本研究采用 6061 铝粉激光增材制造技术制造了两种开尔文开孔金属泡沫热交换器：双层（DKHE）和三层（TKHE）结构，尺寸均为 80 毫米 × 270 毫米 × 210 毫米。在海拔 0 米至 4500 米的高原模拟室中对其性能进行了评估。结果表明，在 0 米处气体流速为 1500m³/h 时，TKHE 和 DKHE 的总传热系数分别为 1625 W/m2-K 和 1301.7 W/m2-K。在 4500 米处，这些数值分别下降了 47.7% 和 37.2%。压降也分别下降了 40% 和 39.2%。面积优良系数表明 TKHE 性能优越。此外，TKHE 的渗透率 K 和惯性系数 fi 均随海拔高度增加，分别比 DKHE 高 36% 和 104%。这项研究将快速成型技术应用于热交换器制造，避免了接触热阻导致的热交换器性能下降。填补了高原地区金属泡沫热交换器性能数据的空白，为今后改进设计奠定了基础。

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引用次数: 0

Close-contact melting enhancement mechanisms in space-constrained and large-space containers 空间受限容器和大空间容器中的近距离接触熔化增强机制

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-13 DOI: 10.1016/j.ijheatmasstransfer.2024.126408

Yongping Huang , Peng Huang , Cheng Yu

To address the critical challenge of low latent heat storage efficiency, this work explores the performance gains of efficient close-contact melting (CCM) compared to traditional constrained melting (CM) in different containers. A novel CCM model based on the quasi-steady-state method is developed and experimentally validated. The comprehensive performance of CM and CCM in space-constrained containers (SCCs) and large-space containers (LSCs) is compared, and the influence of aspect ratio and heat flux density on the performance differences between the two melting modes is investigated. The study indicates that the performance of CM depends on the competition between conduction attenuation and natural convection enhancement, whereas mixed convection in CCM weakens convective heat transfer, with performance primarily dictated by the heat conduction of the thin molten layer. Based on the ranking of the reduction in melting duration of CCM relative to CM, containers with different spatial structures are ordered as follows: LSC (33.8 %) > vertical SCC (17.3 %) >horizontal SCC (3 %). As the aspect ratio approaches 1, the increase in melting rate and thermal homogeneity of CCM relative to CM becomes more significant. For situations where the aspect ratio deviates from 1, the enhancement gain of CCM over CM is greater in vertical SCCs than in horizontal SCCs. Additionally, increased heat flux density weakens the performance enhancement advantage of CCM over CM, especially in horizontal SCCs.

为了解决潜热存储效率低这一严峻挑战，这项研究探索了在不同容器中高效近接触熔化（CCM）与传统受限熔化（CM）相比的性能增益。基于准稳态方法开发了一种新型 CCM 模型，并进行了实验验证。比较了 CM 和 CCM 在空间受限容器 (SCC) 和大空间容器 (LSC) 中的综合性能，并研究了长宽比和热流密度对两种熔化模式性能差异的影响。研究表明，CM 的性能取决于传导衰减和自然对流增强之间的竞争，而 CCM 中的混合对流削弱了对流传热，其性能主要由薄熔层的热传导决定。根据 CCM 相对于 CM 熔化时间缩短程度的排序，不同空间结构的容器排序如下：LSC (33.8%) > 垂直 SCC (17.3%) > 水平 SCC (3%)。当长宽比接近 1 时，CCM 相对于 CM 的熔化率和热均匀性的增加变得更加显著。在纵横比偏离 1 的情况下，垂直 SCC 中 CCM 相对于 CM 的增强增益大于水平 SCC。此外，热通量密度的增加会削弱 CCM 相对于 CM 的性能提升优势，尤其是在水平 SCC 中。

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引用次数: 0

Femtosecond laser-based construction of 3D spatially distributed graphene oxide surface for enhancing boiling heat transfer 基于飞秒激光的三维空间分布氧化石墨烯表面构建，用于增强沸腾传热

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-13 DOI: 10.1016/j.ijheatmasstransfer.2024.126405

Fengwei Ye , Lin Song , Yun Wang , Ying Yang , Ruibo Jin , Jiayao Jiang , Haiyan Tao , Jingquan Lin

To address the difficulties of ultrahigh heat flux transfer in energy and ultra-high heat dissipation applications, pool boiling has been utilized in various extreme heat transfer fields owing to the benefits of high heat flux dissipation. Although graphene-based planar nanocoating with superior in-plane thermal conductivity are employed to enhance heat transfer performance in pool boiling, further improvement of boiling characteristics remains challenging due to the limited and difficult-to-control optimizable factors, such as nanoroughness and wettability. In this work, utilizing a femtosecond laser, a copper substrate with a three-dimensional microstructure topography has been predesigned and fabricated to construct three-dimensional spatially distributed graphene oxide nanocoating surface (3DSD-GO) as a new heat enhancement-optimization strategy in order to obtain a new heat transfer enhancement factor. 3DSD-GO introduces adaptive heat conduction–regional liquid supply mechanism that can adaptively adjust the heat dissipation mode according to the heat distribution of boiling surface to achieve the synergy enhancement of convective heat transfer and phase-change heat transfer. Therefore, 3DSD-GO delays the trigger of the critical heat flux while ensuring the improvement of heat transfer coefficient during nucleate boiling. Additionality, owing to the flexibility of femtosecond laser, GO nanocoating can be formed at a variety of microstructures having different topography and obtain different 3DSD-GO to improve heat transfer performance. Overall, the findings in this work provide a remarkable insight toward breaking the heat transfer limit of graphene-based nanocoating and can be applied in extreme heat transfer fields.

为了解决能源和超高散热应用中超高热流量传递的难题，池沸腾因其高热流量散热的优点而被广泛应用于各种极端传热领域。虽然石墨烯基平面纳米涂层具有优异的面内导热性，可用于提高池沸腾的传热性能，但由于纳米粗糙度和润湿性等可优化因素有限且难以控制，进一步提高沸腾特性仍具有挑战性。在这项工作中，利用飞秒激光预先设计和制造了具有三维微结构形貌的铜基板，以构建三维空间分布氧化石墨烯纳米涂层表面（3DSD-GO）作为一种新的热增强优化策略，从而获得新的传热增强因子。3DSD-GO 引入了自适应热传导-区域供液机制，可根据沸腾表面的热量分布自适应调整散热模式，实现对流传热和相变传热的协同增强。因此，3DSD-GO 可延迟临界热通量的触发时间，同时确保成核沸腾过程中传热系数的提高。此外，由于飞秒激光的灵活性，GO 纳米涂层可以形成各种不同形貌的微结构，从而获得不同的 3DSD-GO 以改善传热性能。总之，这项研究成果为突破石墨烯基纳米涂层的传热极限提供了重要启示，可应用于极端传热领域。

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引用次数: 0

Numerical study for one-dimensional non-isothermal transport of organic contaminant in the three-layer composite liner containing a defective geomembrane 有机污染物在含有缺陷土工膜的三层复合衬垫中的一维非等温迁移数值研究

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-13 DOI: 10.1016/j.ijheatmasstransfer.2024.126417

Wenhao Jiang , Jiangshan Li , Shangqi Ge

The non-isothermal case in bottom composite liners not only induces thermal diffusion behavior, but also alters transport parameters. To date, however, limited work has been done on this topic. The present research constructs a model for one-dimensional non-isothermal transport of organic contaminant in the three-layer composite liner containing a defective geomembrane (GMB), which for the first time systematically includes the impacts of temperature-dependent transport parameters, and also considers the multiple transport mechanisms. The developed model is then solved via finite difference, and its rightness is well-proven through comparisons with the two experiment results and the other calculation approaches. After that, the numerical analysis shows that the temperature-dependent transport parameters exert a combined effect on the transport process, in which changes in diffusion coefficients and hydraulic conductivities with temperature remarkably accelerate the transport rate, whereas such a change for distribution coefficients leads to an opposite trend. The barrier performance assessment suggests that the growth of temperature difference in the composite liner, as well as the GMB defects density, reduces the defined breakthrough time (

t_{b}

) and increases the bottom transport flux. Moreover, 1 cm geosynthetic clay liner is noticed to extend

t_{b}

by approximately 2.23 years, while 0.1 m compacted clay liner yields the increment of

t_{b}

by about 12.1 years. These findings contribute to the reasonable evaluation of bottom composite liners’ barrier performance at a non-isothermal environment, which could provide guidance for optimizing their engineering design.

底部复合内衬的非等温情况不仅会引起热扩散行为，还会改变传输参数。然而，迄今为止，有关这一主题的研究还很有限。本研究构建了一个有机污染物在含有缺陷土工膜（GMB）的三层复合衬垫中的一维非等温迁移模型，该模型首次系统地包含了与温度有关的迁移参数的影响，并考虑了多种迁移机制。然后，通过有限差分法求解所建立的模型，并通过与两次实验结果和其他计算方法的比较，充分证明了该模型的正确性。随后，数值分析表明，与温度相关的迁移参数对迁移过程产生了综合影响，其中扩散系数和导流系数随温度的变化明显加快了迁移速度，而分布系数的变化则导致相反的趋势。阻隔性能评估表明，复合衬垫中温差的增大以及土工合成材料缺陷密度的增加，缩短了规定的突破时间（tb），增加了底部输移通量。此外，1 厘米土工合成粘土衬垫可将 tb 延长约 2.23 年，而 0.1 米压实粘土衬垫可将 tb 延长约 12.1 年。这些发现有助于合理评估底部复合衬垫在非等温环境下的阻隔性能，从而为优化其工程设计提供指导。

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引用次数: 0

A novel method for fast and efficient numerical simulation of microwave heating in liquids during mixing 对混合过程中液体中的微波加热进行快速高效数值模拟的新方法

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-12 DOI: 10.1016/j.ijheatmasstransfer.2024.126425

Bhupinder Singh , Samuel Hefford , Enrique Sanchez-Perez , Michael Barter , Daniel R. Slocombe , Serena A. Cussen , Georgios Dimitrakis

Microwave-assisted chemical reactions present potentially more sustainable routes for process intensification compared with traditional approaches, due to the reduction of reaction times, temperatures, and side reactions. Despite the common misconception that microwave heating is uniform, many processes can be expected to show temperature distributions that vary significantly over the volume, even at length scales far below the operating wavelength. Numerical methods are often employed in the design and optimization phase of a given process, however, due to the multitude of interdependent physics required; the fast and efficient modelling of microwave heating in liquids remains a significant challenge, particularly with respect to computational resources. Here, we report a new multi-physics simulation methodology that models microwave heating of liquids during agitation, requiring less computational resources and delivering temperature predictions within 2.78 % of relative root mean square error. By applying the frozen rotor approach, near-perfect temperature profiles are predicted at approximately 600 times faster convergence time compared to the conventional sliding mesh method. Our proposed model can be used to mimic real reaction systems in a fast and resource-efficient way.

与传统方法相比，微波辅助化学反应可缩短反应时间，降低温度，减少副反应，因此有可能成为更持久的工艺强化途径。尽管人们普遍误认为微波加热是均匀的，但许多工艺过程的温度分布在整个体积上会有显著变化，甚至在远低于工作波长的长度尺度上也是如此。在给定过程的设计和优化阶段，通常会采用数值方法，然而，由于需要大量相互依存的物理因素，液体中微波加热的快速高效建模仍然是一项重大挑战，特别是在计算资源方面。在此，我们报告了一种新的多物理场仿真方法，该方法可对搅拌过程中的液体微波加热进行建模，所需计算资源较少，温度预测的相对均方根误差在 2.78% 以内。通过应用冷冻转子方法，与传统的滑动网格方法相比，预测近乎完美的温度曲线的收敛时间快了约 600 倍。我们提出的模型可用于以快速和节省资源的方式模拟真实反应系统。

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引用次数: 0

A novel formulation for heat conduction using non-convex meshes based on smoothed finite element method 基于平滑有限元法的非凸网格热传导新公式

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-12 DOI: 10.1016/j.ijheatmasstransfer.2024.126310

Shao-Wei Wu , Rui Yang , Rui-Ping Niu , Li-Xiong Cao , Xin Liu , De-Tao Wan , Gui-Rong Liu

A novel formulation for non-convex polygon mesh based on cell-based smoothed finite element method (CS-FEM) is presented for analyzing heat conduction. The major ingredient of this article include: 1) An inverse coordinate mapping method is proposed by using arbitrary polygons of shapes such as "dog", "bird", "cow" obtained from images to discretize the problem domain; 2) The Ear clipping triangulation technique is used to construct a triangular smoothing domain consisting only of field nodes; 3) The element integral is transformed into the boundary integral of triangular smoothing domain, thereby achieving temperature gradient smoothing operation, using the gradient smoothing technique, Well behaved smoothed stiffness matrix is achieved through the gradient smoothing technique of S-FEM in concave polygon elements without the need to construct additional stability terms. Based on the weakened weak form theory, the discretized system equations of heat conduction problem are established, which a symmetric and well-conditioned. The efficacy and robustness of the proposed method has been has been demonstrated through a number of benchmark examples including multi-material systems. It can effectively solve heat conduction problems using concave polygon elements, allowing materials with complex configuration being effectively modeled.

本文提出了一种基于单元平滑有限元法（CS-FEM）的非凸多边形网格新公式，用于分析热传导。本文的主要内容包括1) 提出了一种反坐标映射方法，使用从图像中获取的 "狗"、"鸟"、"牛 "等形状的任意多边形来离散问题域；2) 使用 "Ear clipping triangulation "技术来构建仅由场节点组成的三角形平滑域；3) 将元素积分转换为三角形平滑域的边界积分，从而实现温度梯度平滑操作，利用梯度平滑技术，通过 S-FEM 在凹多边形元素中的梯度平滑技术实现了良好的平滑刚度矩阵，而无需构建额外的稳定项。基于弱化弱形式理论，建立了对称且条件良好的热传导问题离散化系统方程。通过大量基准实例，包括多材料系统，证明了所提方法的有效性和稳健性。它能使用凹多边形元素有效地解决热传导问题，并能对具有复杂构造的材料进行有效建模。

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引用次数: 0

Alternating conduction and convection drying of paper – an experimental analysis with a continuous data acquisition approach 纸张的交替传导和对流干燥--采用连续数据采集方法的实验分析

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Heat and Mass Transfer

Pub Date : 2024-11-12 DOI: 10.1016/j.ijheatmasstransfer.2024.126400

Koushik Sampath, Huajiang Huang, Shri Ramaswamy

In conventional multi-cylinder drying of paper and board, both conductive drying from steam-heated dryer cylinders and convective drying by flowing air over the paper surface in the pockets are used. Conductive drying from steam-heated drying cylinders is a critical component in providing the necessary thermal energy to paper and board as they dry. Steam temperature and internal and external resistances at the contacting surface are critical process parameters influencing the conductive drying process. An experimental setup was developed to study the alternating conductive and convective drying of paper and board. Paper sheet moisture, temperature, and temperature distribution within the heated platen and the instantaneous heat flux as the sheet was being dried were measured. The instantaneous heat flux, contact heat transfer coefficient, and drying rates were determined as drying proceeds. Experimental results, as well as comparisons to literature and commercial data, are presented. The conductive heat transfer coefficients determined were compared to traditional correlations normally used in the modeling of paper drying. Similarly, the convective heat and mass transfer coefficients are also determined and compared to literature data. In addition to the evaluation of alternating conductive and convective drying characteristics of paper and board, the potential inclusion of auxiliary energy components will also be included. Experimental results from the conduction and convection drying system are presented. This data will be useful in process development, intensification of manufacturing processes, and modeling and simulation of paper drying processes.

在纸和纸板的传统多缸干燥过程中，既要使用蒸汽加热的干燥缸进行传导干燥，也要使用空气在纸张表面的口袋中流动进行对流干燥。蒸汽加热烘缸的传导式干燥是在纸和纸板干燥过程中为其提供必要热能的关键部分。蒸汽温度和接触面的内外阻力是影响传导干燥过程的关键工艺参数。我们开发了一套实验装置来研究纸张和纸板的交替传导和对流干燥。测量了纸张的水分、温度、加热压板内的温度分布以及纸张干燥时的瞬时热通量。测定了干燥过程中的瞬时热通量、接触传热系数和干燥速率。实验结果以及与文献和商业数据的比较均已公布。测定的传导传热系数与通常用于纸张干燥建模的传统相关系数进行了比较。同样，还测定了对流传热和传质系数，并与文献数据进行了比较。除了对纸张和纸板的交替传导和对流干燥特性进行评估外，还将对可能包含的辅助能量成分进行评估。介绍了传导和对流干燥系统的实验结果。这些数据将有助于工艺开发、生产工艺强化以及纸张干燥工艺的建模和模拟。

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引用次数: 0