Zhenpeng Wang, Yuchuan Guo, Xiaoyu Guo, Jie Fan, Simao Guo, Bin Tang
{"title":"Improved numerical model of high temperature variable conductance heat pipe based on network method: Application in residual heat removal system for marine heat pipe reactor","authors":"Zhenpeng Wang, Yuchuan Guo, Xiaoyu Guo, Jie Fan, Simao Guo, Bin Tang","doi":"10.1016/j.applthermaleng.2025.128611","DOIUrl":"10.1016/j.applthermaleng.2025.128611","url":null,"abstract":"<div><div>The Variable Conductance Heat Pipe, containing non-condensable gas for regulating heat transfer capability, have great application potential in passive heat transfer and residual heat removal processes of nuclear reactors. However, complex phenomena such as two-phase boiling flow and the coupling of non-condensable gas cavity compression/release pose significant challenges for numerical simulation of Variable Conductance Heat Pipe. Because the existing numerical models for variable-conductance heat pipes is limited and the demand for transient computation in engineering is growing., this study proposes a new efficient Variable Conductance Heat Pipe model. This model integrates the network method, the flow pressure drop calculation for vapor space, and a Variable Conductance Heat Pipe plane interface theory. This model enables efficient transient simulation of Variable Conductance Heat Pipe by treating the physical processes as purely solid-state heat conduction. The accuracy is validated and compared to other Variable Conductance Heat Pipe models, achieving accelerated computation without sacrificing accuracy. Effects of heating power, charge quantity, and non-uniform heating conditions on heat pipe temperature and non-condensable gas behavior are analyzed. Applied to the heat-pipe reactor residual heat removal system, the model reveals the dynamic response of temperature following reactor shutdown, confirming the feasibility of using Variable Conductance Heat Pipe as thermal switches in such systems.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128611"},"PeriodicalIF":6.9,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264717","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}
Yongjun Choi, Ji Yong Choi, Young Uk Kim, Sumin Kim
{"title":"Hybrid paper membranes incorporated with carbon and phase change materials for improved thermal performance","authors":"Yongjun Choi, Ji Yong Choi, Young Uk Kim, Sumin Kim","doi":"10.1016/j.applthermaleng.2025.128624","DOIUrl":"10.1016/j.applthermaleng.2025.128624","url":null,"abstract":"<div><div>Energy recovery ventilators (ERVs) are essential for improving indoor air quality (IAQ) and reducing energy consumption. However, conventional membranes often lack thermal storage capability and long-term durability. This study developed a composite paper membrane by impregnating a pulp-derived corrugated substrate with n-octadecane-based phase change material (PCM) and carbon additives, including carbon nanotubes (CNTs), exfoliated graphite nanoplatelets (xGnP), graphene, and activated carbon (AC), to enhance thermal regulation and moisture permeability. Thermal conductivity measurements, differential scanning calorimetry, thermogravimetric analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy, and dynamic thermal tests were conducted for performance evaluation. The results show that PCM integration significantly improved the composite paper membranes, which exhibited a latent heat storage equivalent to 68 % of the latent heat value of pure PCM. Carbon additives improved heat transfer efficiency and increased thermal conductivity, promoting uniform temperature distribution during heating and cooling cycles. Moisture permeability was maintained, with <em>S<sub>d</sub></em> values below 1 m, meeting ISO 12572 standards for breathable membranes. Durability evaluation through 1,000 thermal cycles, equivalent to approximately three years of ERV operation, confirmed consistent latent heat capacity and structural integrity. Dynamic testing also demonstrated a slower cooling rate and reduced heat dissipation, indicating the potential of these membranes to buffer indoor environments under variable outdoor conditions. The PCM–carbon composite paper membrane provides a cost-effective and environmentally sustainable alternative to polymer-based ERV membranes, offering dual functionality—moisture control and thermal energy storage—while improving ventilation performance and contributing to low-emission building technologies.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128624"},"PeriodicalIF":6.9,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264718","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}
{"title":"Influence of jet parameters on cooling performance of liquid film formed by impingement","authors":"Haosen Zhang, Jianwei Zhang, Ruizhi Li","doi":"10.1016/j.applthermaleng.2025.128498","DOIUrl":"10.1016/j.applthermaleng.2025.128498","url":null,"abstract":"<div><div>Liquid film cooling is a crucial thermal protection method for space attitude and orbit control engines. After impinging on the wall surface, coolant jets spread outward, forming a liquid film. When the film contacts the high-temperature wall, it may undergo boiling. Most related studies focus on transient quenching conditions, examining variation in film size, wetting front, and other parameters. However, the steady-state operational characteristics of liquid film cooling remain unclear. This study employs Eulerian and Rensselaer Polytechnic Institute (RPI) models for parametric simulations to investigate the effect of jet parameters on film flow, heat transfer and wall thermal response. The mechanisms underlying these effects are analyzed. Cooling efficiency is evaluated using specific heat absorption and sensible heat utilization as key metrics. A relative range analysis is conducted to assess the impact intensity of various jet parameters on cooling performance. Results indicate that jet parameters significantly affect liquid film cooling performance, influencing the flow and heat transfer of the liquid film through the Pe number, under the control of boundary layer. To enhance cooling effectiveness, adjustments should primarily focus on subcooling and jet diameter. Conversely, optimizing film utilization requires modifications to the jet angle.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128498"},"PeriodicalIF":6.9,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145227719","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}
Junyang Xie , Chong Yao , Bo Wang , Chendong Wu , Yusong Wang , Enzhe Song
{"title":"Data-driven multi-objective optimization for combustion control in marine diesel- micro-ignited dual-fuel engines: resolving the NOx-efficiency trade-off","authors":"Junyang Xie , Chong Yao , Bo Wang , Chendong Wu , Yusong Wang , Enzhe Song","doi":"10.1016/j.applthermaleng.2025.128635","DOIUrl":"10.1016/j.applthermaleng.2025.128635","url":null,"abstract":"<div><div>This study investigates the impact of pre-injection strategies on combustion characteristics, emission performance, and fuel efficiency in diesel-micro-piloted natural gas engines based on modified marine high-pressure common rail diesel engines. Experimental results demonstrate that pre-injecting diesel under this micro-pilot dual-fuel operation significantly accelerates natural gas combustion, resulting in an 87.36 % increase in NOx emissions. This reveals a critical pitfall: a strategy designed to create a more homogeneous, low-temperature combustion mode instead triggers a high-temperature combustion event, contradicting the expected benefits of such a strategy. While high-pressure main injection alone can achieve a more desirable two-stage heat release profile, its thermal efficiency remains unsatisfactory. Through data-driven modeling (Gaussian Process Regression/XGBoost) and multi-objective optimization (NSGA-II), the research identifies speed-dependent optimal control strategies. The optimized system achieves NOx emissions as low as 1.7 g/kWh at medium speed and below 2.1 g/kWh across all tested speed ranges, successfully meeting IMO Tier III standards while maintaining brake thermal efficiency (BTE) above 40 % (specifically, between 40.5 % and 41.8 %). These findings provide critical references for retrofitting and calibrating diesel-micro-piloted natural gas engines in marine applications.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128635"},"PeriodicalIF":6.9,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264711","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}
Peiyong Ni , Yunlong Zhang , Zhuonan Chen , Xiangli Wang , Xuewen Zhang , Xiang Li
{"title":"Optimization and thermal performance evaluation of a closed-loop water-cooling system for thermoelectric generators","authors":"Peiyong Ni , Yunlong Zhang , Zhuonan Chen , Xiangli Wang , Xuewen Zhang , Xiang Li","doi":"10.1016/j.applthermaleng.2025.128606","DOIUrl":"10.1016/j.applthermaleng.2025.128606","url":null,"abstract":"<div><div>A closed water-cooled system with an optimized heat sink is presented for thermoelectric generators to overcome the limitations of conventional open cooling water system designs in terms of water consumption and applicability. Parametric CFD simulations were employed to systematically optimize the geometric configuration of fins and flow channels. Simulation results reveal that thermal performance improves with increased fin height, channel length, or cross-sectional area, whereas wider fin spacing reduces effectiveness due to diminished convective heat transfer. Experimental validation under variable operating conditions demonstrates optimal performance at a flow rate of 2 L/min, achieving a peak heat dissipation power of 331 W. The system attains thermal equilibrium within 17 minutes, with temperature fluctuations below 2.1 °C for the heat sink and 1.1 °C for the cooler. Key findings reveal that fin geometric parameters dominate thermal performance, with the height-to-spacing ratio critical for balancing heat transfer area and turbulence. An intermediate flow rate optimizes the trade-off between mass flow and temperature gradient, while time-dependent experimental analysis proves essential for system stability. This study provides a validated framework for designing compact, water-efficient TEG cooling systems, offering significant potential for waste heat recovery in energy-intensive applications.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128606"},"PeriodicalIF":6.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264723","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}
{"title":"Design and performance analysis of liquid organic hydrogen carriers supply HT-PEMFC systems","authors":"Qingyun Luo, Sheng Yang","doi":"10.1016/j.applthermaleng.2025.128550","DOIUrl":"10.1016/j.applthermaleng.2025.128550","url":null,"abstract":"<div><div>This study proposes a novel multi-purpose system integrating liquid organic hydrogen carriers with high-temperature proton exchange membrane fuel cells. It innovatively couples the organic Rankine cycle, ammonia vapor compression refrigeration cycle, lithium chloride solution dehumidification cycle, and lithium bromide absorption refrigeration cycle to achieve multifunctional synergy in electricity generation, cooling, humidity control, and hot water supply. Based on Aspen Plus modelling, the system performance was evaluated across three dimensions: thermodynamics, exergy analysis, and uncertainty. Results indicate that under specified operating conditions, the system achieves net electricity efficiency of 41.79%, exergy efficiency of 79.72%, dehumidification rate of 85.1%, and coefficient of performance of 5.31 for the air conditioning and dehumidification system. The overall system energy efficiency stands at 1.6, demonstrating a significant advantage over existing research. In particular, the high-temperature proton exchange membrane fuel cell exhibits the highest exergy loss ratio, accounting for 62.3% of total losses. Uncertainty analysis indicates that among external parameters, fuel input volume exerts the most significant influence on system performance; internally, the exchange current density plays a dominant role. This research breaks through the primary limitation that the integration of liquid organic hydrogen carriers with proton exchange membrane fuel cells has been confined to automotive applications. It expands avenues for the high-value use of liquid organic hydrogen carriers, holding significant engineering application value for advancing the sustainable development of the hydrogen economy.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128550"},"PeriodicalIF":6.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264219","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}
Fayez Alruwaili, Kevin J. Hughes, Derek B. Ingham, Lin Ma, Mohamed Pourkashanian
{"title":"Techno-economic assessment of a commercial natural gas combined cycle with a chemical absorption plant using lean vapor compression modification","authors":"Fayez Alruwaili, Kevin J. Hughes, Derek B. Ingham, Lin Ma, Mohamed Pourkashanian","doi":"10.1016/j.applthermaleng.2025.128619","DOIUrl":"10.1016/j.applthermaleng.2025.128619","url":null,"abstract":"<div><div>The primary challenge in integrating post-combustion CO<sub>2</sub> capture (PCC) with natural gas combined cycle (NGCC) is the significant energy consumption and capital costs. The novelty of this paper lies in proposing for the first time an advanced novel configuration that combines lean vapor compression (LVC) for the PCC plant with the NGCC plant incorporating exhaust gas recirculation (EGR) and selective exhaust gas recirculation (SEGR). The simulation results illustrated that implementing 33 % EGR can increase the CO<sub>2</sub> level in exhaust gas from a baseline of 4.2 to 6.3 mol%. In comparison, 53 % SEGR increased the CO<sub>2</sub> concentration in the flue gas to 8.8 mol%. Among the different configurations examined, SEGR + LVC achieved the highest energy saving for reboiler duty, which was 14 % compared to the baseline. In contrast, the EGR + LVC recorded the highest enhancement in thermal efficiency by 0.7 % points compared to the reference case. The LVC alone resulted in approximately 0.4 % points improvement in thermal efficiency for all configurations evaluated when the gas turbine loads were reduced from 100 to 60 %. This indicates that LVC is effective under partial loads. Finally, SEGR + LVC results in the greatest cost reduction for the PCC plant equipment, lowering the cost by 26 % compared to the baseline. However, the SEGR has the highest total plant cost and total overnight cost due to additional costs for the CO<sub>2</sub> membrane separation system.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128619"},"PeriodicalIF":6.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264404","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}
{"title":"Performance evaluation of combined heat and power unit equipped with rear heating turbine and heat storage tank","authors":"Xinze Li, Xinyu Guo, Guanyu Ren, Wenjing Du","doi":"10.1016/j.applthermaleng.2025.128616","DOIUrl":"10.1016/j.applthermaleng.2025.128616","url":null,"abstract":"<div><div>Combined heat and power (CHP) units face two challenges: considerable exergy loss during heating and heat-power coupling. For this reason, this study proposes a new unit featuring a rear heating turbine (RHT) and a heat storage tank (HST). A numerical RHT & HST unit model was constructed to evaluate its performance improvements from thermodynamic and flexibility perspectives. To quantify the practical benefits of the RHT & HST unit, a modified genetic algorithm (GA) was developed to solve the HST daily dispatch model, with a backpropagation neural network introduced to improve the model’s objective function accuracy. The results indicate that the RHT & HST unit performed energy cascade utilization of heating extraction steam, demonstrating higher energy and exergy efficiencies, with an increase of 21.8 % in the heating process’s exergy efficiency. Furthermore, its flexibility surpasses traditional units, with a maximum heating capacity increase of 62 MW during deep peak shaving. Compared to conventional GA, the modified GA shows significant improvements in objective function accuracy and computational efficiency. After optimizing dispatch using this algorithm, HST can effectively perform peak shaving and valley filling for heat load, enabling the unit to operate within a more efficient economic range. During the heating season, the RHT & HST unit expects to save approximately 27,257 tons of coal, reduce carbon emissions by about 71,359 tons, and generate around 14.213 million CNY in additional revenue. This study offers guidance on flexibility and energy-saving retrofits for CHP units.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128616"},"PeriodicalIF":6.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264218","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}
{"title":"CFD-DEM investigation of cluster dynamics and moisture transfer behavior in a binary fluidized bed","authors":"Zexin Zhong , Xiaoke Ku , Jianzhong Lin","doi":"10.1016/j.applthermaleng.2025.128613","DOIUrl":"10.1016/j.applthermaleng.2025.128613","url":null,"abstract":"<div><div>The addition of dry bed material can enhance dehydration by improving heat and mass transfer in binary fluidized beds. Using computational fluid dynamics-discrete element method (CFD-DEM) coupled with liquid evaporation and transfer models, the fluidization, clustering, and dehydration performance of wet particles are explored. The effects of adding dry bed material, initial stacking arrangement, bed material density, and inlet velocity configuration are systematically examined. The results reveal that the addition of bed material can increase the cluster peak volume but weaken its stability. Density differences between the bed material and wet particles can induce segregation, which can be mitigated through optimized inlet velocity configurations. Moreover, the initial stacking arrangement influences the mixing behavior and cluster dynamics. All these observations are beneficial for a deeper understanding of the fluidization, clustering, and dehydration behavior of wet particles in binary fluidized beds.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128613"},"PeriodicalIF":6.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264319","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}
{"title":"Experimental investigation of secondary flow effect caused by internal heat generation in the horizontal laminar pipe flow","authors":"Dong-Hyuk Park, Bum-Jin Chung","doi":"10.1016/j.applthermaleng.2025.128563","DOIUrl":"10.1016/j.applthermaleng.2025.128563","url":null,"abstract":"<div><div>In the Liquid-fueled Molten Salt Reactors (MSRs), the nuclear fuel is dissolved within the fluid, serving as the heat source and resulting in a non-homogeneous energy equation. Understanding the resulting thermal–hydraulic behavior is essential for the design and safety evaluation of MSRs. This study experimentally investigated laminar horizontal pipe flow with internal heat generation. Uniform volumetric heat generation was achieved by electrical dissipation of an H<sub>2</sub>SO<sub>4</sub> electrolyte solution. By varying the Reynolds number and heat generation rate, circumferential and axial wall temperature distributions were measured. The presence of internal heat generation led to elevated wall temperatures, attributed to low fluid velocity near the wall. These temperature gradients induced buoyancy forces, resulting in thermal stagnation in the top region of the pipe and the development of secondary flow beneath this region. This phenomenon contributed to localized hot spots on the top region and wall temperature reduction at the lower region. Based on the experimental data, empirical correlations for the dimensionless wall temperature were developed. To the best of our knowledge, this study presents the first experimental observation of secondary flow effects in internally heated horizontal laminar pipe flow.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"281 ","pages":"Article 128563"},"PeriodicalIF":6.9,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145264714","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}