Applied Thermal Engineering最新文献

{"title":"Thermal performance enhancement and multi-parameter optimization of an innovative double helical fin-reinforced coaxial casing geothermal heat exchanger","authors":"Zhicheng Fang,&nbsp;Chuntian Zhao,&nbsp;Hongmei Li","doi":"10.1016/j.applthermaleng.2025.128145","DOIUrl":"10.1016/j.applthermaleng.2025.128145","url":null,"abstract":"<div><div>To address the fundamental challenge of insufficient heat transfer rate that limits the development of geothermal energy, this study proposes a novel design of a double-helical finned coaxial tube heat exchanger, and conducts comprehensive thermodynamic characterization and structural optimization. Through computational fluid dynamics (CFD) numerical simulation, a three-dimensional numerical model was established to evaluate four different fin configurations: co-rotating double-helical fins on inner and outer tubes, counter-rotating double-helical fins on inner and outer tubes, double-helical fins only on the outer surface of the inner tube, and double-helical fins only on the inner surface of the outer tube; these configurations were also compared with a baseline smooth tube. Thermal performance indicators including heat transfer rate, Nusselt number (Nu), friction factor (f), and entropy generation were systematically evaluated. The results show that the counter-rotating helical fin configuration achieves excellent comprehensive thermodynamic performance. Under the operating condition of Reynolds number Re = 16,000, the Performance Evaluation Criterion (PEC) analysis indicates that the heat transfer rate is increased by 35 % compared with the baseline configuration, and the PEC value reaches 1.35. Single-factor parameter analysis clarifies the influence mechanism of key geometric variables—including pitch (P), number of fins (N), fin height (H), and fin thickness (<span><math><mi>δ</mi></math></span>)—on heat transfer and flow characteristics. The study reveals that reducing the pitch value, using a moderate number of fins, increasing the fin height while decreasing the thickness can optimize the balance between heat transfer enhancement and hydraulic loss. Furthermore, the Box-Behnken response surface methodology was used to establish a second-order prediction model (R² = 0.982), and multi-parameter optimization was achieved through the particle swarm optimization algorithm. The determined optimal geometric parameters are: pitch of 210 mm, 14 fins, height of 12 mm, and thickness of 3 mm. Compared with the baseline design, this optimal configuration achieves an 8.7 % improvement in thermal performance and a 12.3 % reduction in pressure loss.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128145"},"PeriodicalIF":6.9,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989697","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":"A novel waste heat power generation system based on the integration of Carnot battery and waste heat recovery in a cement plant","authors":"Yuhan Zhao,&nbsp;Heng Chen,&nbsp;Yixi Zhang,&nbsp;Zhongcheng Jin,&nbsp;Peiyuan Pan,&nbsp;Guoqiang Zhang","doi":"10.1016/j.applthermaleng.2025.128159","DOIUrl":"10.1016/j.applthermaleng.2025.128159","url":null,"abstract":"<div><div>This paper proposes a novel design system that couples the Carnot battery with waste heat recovery power generation technology in cement kilns. The Carnot battery recovers and reutilizes the heat in the gas, using the gas discharged from the cement kiln to heat the regenerated CO₂. The compressor elevates both gaseous pressure and thermal conditions of CO₂, subsequently facilitating energy exchange with the circulating coolant medium in the thermal transfer unit. The heat is then stored in the thermal storage tank and is used to heat feedwater to produce electricity. A system model comprising the Carnot battery and cement kiln waste heat power generation unit was first established using the EBSILON Professional 16.02 platform. Subsequently, energy analysis, exergy analysis, economic analysis, and sensitivity analysis were conducted on the system model. The research results indicate that the system has a power generation efficiency of 21.85 % and an exergy efficiency of 53.75 %. The recovery and utilization of waste heat significantly improve the COP of the Carnot battery. The payback period of the system is 8.67 years, with a net present value of 13396.27 k$, indicating high economic viability. Optimizing the Carnot battery’s performance can be achieved by lowering the compressor’s discharge temperature, elevating the intake temperature, and moderately reducing the fluid’s circulation rate, all of which contribute to improved COP.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128159"},"PeriodicalIF":6.9,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989699","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":"Heat transfer characterization and enhancement of spherical latent heat thermal energy storage unit under forced convection boundary conditions","authors":"Long Gao ,&nbsp;Han Yue ,&nbsp;Yimin Deng ,&nbsp;Jing Fan ,&nbsp;Lizhong Yang","doi":"10.1016/j.applthermaleng.2025.128132","DOIUrl":"10.1016/j.applthermaleng.2025.128132","url":null,"abstract":"<div><div>Latent heat thermal energy storage (LHTES) spheres offer high energy density; however, existing experimental research predominantly relies on uniform-temperature boundary conditions, which fail to reflect real-world forced convection environments accurately. This study investigates the charging process of an LHTES sphere under non-uniform forced convection boundary conditions, a crucial aspect often overlooked. Combined experimental and numerical analysis revealed that the non-uniform forced convection generates an external flow field that causes heat transfer instability at the sphere’s bottom due to vortex fluctuations. Meanwhile, the surface temperature gradient stimulates natural convection within the phase change material (PCM). Using the validated numerical model that is consistent with the real conditions, methods to enhance the heat transfer can be evaluated with improved accuracy and reliability. Adding carbon nanotubes (CNTs) shortens the charging time, but the average effective power density increases initially and then decreases with the rise in CNT volume fraction, while the entropy generation to entropy change ratio increases linearly. Optimizing the fin structure also reduces the charging time, but the reduction rate decreases as the number of fins increases. The entropy generation to entropy change ratio first decreases and then increases, and effective power density continues to rise, but at a slower pace. Synergistic optimization of CNT addition and fin configuration improves average effective power density by 35.94% and reduces entropy generation to the entropy change ratio by 1.46% compared to conventional spheres. This research emphasizes the significant impact of non-uniform forced convection boundary conditions on heat transfer characteristics and provides a practical approach for enhancing heat transfer in LHTES spheres with higher accuracy.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128132"},"PeriodicalIF":6.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004525","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":"Numerical investigation of the thermal performance of CPCM in T-slot profile channel for potential compactness in modular energy storage","authors":"Sheher Yar Khan ,&nbsp;Shuli Liu ,&nbsp;Yongliang Shen ,&nbsp;Mahroo Eftekhari ,&nbsp;Jihong Wang ,&nbsp;Mahesh Kumar ,&nbsp;Abdur Rehman Mazhar ,&nbsp;Wenjie Ji ,&nbsp;Arvin Sohrabi ,&nbsp;Tingsen Chen ,&nbsp;Chongjie Xiong","doi":"10.1016/j.applthermaleng.2025.128139","DOIUrl":"10.1016/j.applthermaleng.2025.128139","url":null,"abstract":"<div><div>The encapsulation of advanced solid rigid composite phase change materials (CPCMs), primarily in solid-pellet form, presents significant challenges when applied to complex geometries, especially those with internal fins featuring intricate curved or branched structures. For example, biomimetic-inspired designs can hinder the proper placement of standard-shaped pellets. Additionally, external fins intended to enhance discharging increase the overall channel domain, consequently reducing system compactness in modular form. To overcome these limitations, square variants of the T-slot profile are proposed to provide defined spaces for CPCM pellets with a centrally located heat source for uniform symmetrical charging. The curved slots extend the heat transfer pathways, creating a fin-like effect internally that enhances charging performance, while also increasing the external heat transfer area to facilitate effective discharging without the need for additional expansion of the original domain. A comprehensive numerical analysis of the proposed models is conducted to compare the performance against a reference geometry of equal domain and having the same amount of PCM. The numerical scheme is validated against a lab-scale experimental prototype, not relying on previously published models for validation. The T-slot variants showed up to 27.9 % faster charging, with 9.69–14.7 % time savings for G2 and G3. Charging heat transfer coefficients improved to 60.8–73.9  W/m²·K vs. 56.7 for the reference. During discharging, heat extraction increased with coefficients up to 74.90  W/m²·K, demonstrating significantly enhanced thermal performance across all T-slot geometries. Overall, other performance parameters in the study further highlight the power and cost-effectiveness potential of the proposed designs.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128139"},"PeriodicalIF":6.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997421","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":"Mechanism of droplet rebound failure induced by temperature difference-driven condensation on superhydrophobic surfaces","authors":"Zeyu Kong,&nbsp;Zexiang Yan,&nbsp;Yalin Tang,&nbsp;Zhaoyang Ou,&nbsp;Kun Zhang,&nbsp;Xianglian Lv,&nbsp;Weizheng Yuan,&nbsp;Yang He","doi":"10.1016/j.applthermaleng.2025.128131","DOIUrl":"10.1016/j.applthermaleng.2025.128131","url":null,"abstract":"<div><div>Droplet impact behavior on superhydrophobic surfaces plays a crucial role in various thermal management applications, particularly in anti-icing, condensation heat transfer, and moisture control. While extensive studies have focused on freezing-induced adhesion, rebound failure can also occur under non-freezing conditions, where conventional explanations are insufficient. In this study, we systematically conducted droplet impact experiments on cold superhydrophobic surfaces under controlled temperature difference (ΔT) conditions between the droplet and the surface. The results demonstrate that rebound behavior is primarily governed by ΔT rather than the individual temperatures of the droplet and surface. When ΔT exceeds a critical threshold of 15 °C, droplet rebound begins to fail due to intensified interfacial condensation, which forms liquid bridges inside surface microstructures and significantly increases energy dissipation. This temperature-difference-driven interfacial condensation mechanism provides new insights into dynamic wetting failure under thermal gradients, and suggests potential strategies for improving surface design in condensation management, anti-icing, and cold-environment heat exchange systems.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"279 ","pages":"Article 128131"},"PeriodicalIF":6.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144925273","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":"Homogenization of solar furnace concentrated flux over a cylindrical receiver","authors":"Helena Luna-García ,&nbsp;Leopoldo Martínez-Manuel ,&nbsp;Cuitlahuac Iriarte-Cornejo ,&nbsp;Heidi I. Villafán-Vidales ,&nbsp;David Riveros-Rosas ,&nbsp;Camilo A. Arancibia-Bulnes","doi":"10.1016/j.applthermaleng.2025.128068","DOIUrl":"10.1016/j.applthermaleng.2025.128068","url":null,"abstract":"<div><div>Secondary mirrors (SM) can significantly enhance the homogeneity of the flux produced by solar concentrators, reducing thermal gradients in receivers. Two cases of Secondary Mirror designs are proposed here to uniformize the flux of a solar furnace over a cylindrical reactor: an elliptic cone and a flat-faceted mirror. The axis of the cylindrical reactor is perpendicular to the optical axis of the concentrator, a problem not previously addressed in the literature, where part of the challenge is the transformation of the point-focus flux into a line-focus distribution by the SM. Monte Carlo Ray Tracing simulations were employed to evaluate the optical performance and optimize the proposed secondary mirrors in terms of flux uniformity and optical efficiency. Additionally, a computational fluid dynamics analysis was conducted to assess the impact of flux homogenization on the reactor’s temperature distribution and overall thermal efficiency. The faceted SM was more effective for homogenization than the elliptic cone, increasing uniformity by more than 80% and reducing peak flux by more than 90%. Furthermore, the thermal analysis confirmed that the optimized flux distribution of both types of SM leads to significantly reduce thermal gradients.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128068"},"PeriodicalIF":6.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933139","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 analysis on direct-expansion refrigeration-cold storage integrated cold plates","authors":"Zhiwei Ouyang ,&nbsp;Abdulaziz Mohammed T.A ,&nbsp;Luohan Liu ,&nbsp;Fei Zhao ,&nbsp;Xinglong Ma","doi":"10.1016/j.applthermaleng.2025.128138","DOIUrl":"10.1016/j.applthermaleng.2025.128138","url":null,"abstract":"<div><div>Phase change energy storage plays a significant role in enhancing the utilization of renewable energy, particularly in the integration of PV systems with cold chain transportation. However, the phase change materials (PCMs) currently used in refrigerated vehicles are mostly configured as separate modules, which require a second circulation for cold charging and discharging. This leads to the decoupling of the charging and cooling processes, thereby preventing their simultaneous occurrence. This study proposes a direct-expansion refrigeration and cold-storage integrated cold plate, which offers the dual advantages of space conservation and simultaneous PCM charging during active refrigeration. Thus, the PCM in cold plate continues to provide stable cooling after the refrigeration unit is turned off and this would expend the halting interval of the refrigeration unit. A test chamber (1.53 × 1.11 × 1.11 m³) was constructed and equipped with the integrated cold plates for experimental validation. Under no-load conditions and within the operating temperature range of 2–8 °C, the system demonstrated that the threshold time, discharge efficiency, maximum mean temperature deviation, and average hourly electricity consumption reached 2.2 h, 51.73 %, 3.36 °C and 0.087 kWh, respectively. Compared to the configuration without PCM, this represents an energy saving of 0.035 kWh. Moreover, enhancing convective airflow within the chamber reduced the threshold time and discharge efficiency to 0.53 h and 24.91 %, respectively, while increasing the average hourly electricity consumption to 0.348 kWh. However, it contributed to a more uniform temperature distribution within the chamber. This research is expected to provide a technical reference for the energy-efficient design of cold chain containers.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128138"},"PeriodicalIF":6.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989104","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":"A novel 3D-CFD-simulation-based model to predict potential boiling-related erosion damage in engine cooling circuits","authors":"Pietro Pigani ,&nbsp;Fabio Berni ,&nbsp;Giovanni Paini ,&nbsp;Roberto Tonelli ,&nbsp;Stefano Fontanesi","doi":"10.1016/j.applthermaleng.2025.128130","DOIUrl":"10.1016/j.applthermaleng.2025.128130","url":null,"abstract":"<div><div>In recent years, the increasing power density of reciprocating internal combustion engines has posed significant challenges to maintain optimal temperature conditions and to preserve thermo-mechanical reliability. In order to improve the cooling circuit performance, local nucleate boiling has become a key phenomenon to promote pointwise heat transfer. However, experimental studies also revealed that, in presence of boiling, surface erosion can potentially occur in specific areas of the engine (especially the head), based on operating conditions and geometry of the cooling circuit. In this context, the development of a dedicated tool able to accurately predict the occurrence of boiling-induced erosion is essential to optimize design and thermal management of the engine, in order to mitigate the onset of potential severe damages.</div><div>A 3D-CFD tool to predict damage in cooling circuits is proposed in the present work and it relies on both a conjugate heat transfer model of the engine and a novel purposely developed parameter. As for the former, it provides a detailed description of the engine and it is characterized by an accurate modelling of the boiling phenomenon. As for the latter, despite the availability of numerous erosion models in the context of cavitation, no reliable or widely accepted tool currently exists for predicting material surface erosion caused by the collapse of vapor bubbles in presence of boiling. In the paper, a model is proposed, based on the latest research findings available in literature on the vapor bubble condensation process. The model is synthetized by a novel erosion parameter, which accounts for key factors influencing the bubble collapse phenomenon, including vapor fraction, liquid subcooling level, thermal gradient and local velocity field. The higher the erosion parameter is, the higher the risk of severe damage results.</div><div>The CFD tool is validated against experimental data on two different high-performance engines. The CHT model thermal field is compared to temperatures from thermocouples installed at the test bench. The predicted regions of potential boiling-induced damage, indicated by peaks of erosion parameter distribution, exhibit strong correlation with the experimental images showing the regions of severe damage.</div><div>Interestingly, although the erosion parameter is developed to investigate damage in high-performance current-production reciprocating internal combustion engines, it can be applied, in principle, to any engine or cooling circuit. In addition, the implementation is straightforward as it is just a post-processing tool. Therefore, it can be applied to elaborate the results of any existing simulation.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128130"},"PeriodicalIF":6.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004648","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":"An experimental research on the vacuum spray flash evaporation of ethanol–water solution","authors":"Benan Cai,&nbsp;Yuqi Zhao,&nbsp;Yutong Sun,&nbsp;Rong Wang,&nbsp;Jincheng Wang,&nbsp;Xunjian Che,&nbsp;Weihua Cai","doi":"10.1016/j.applthermaleng.2025.128133","DOIUrl":"10.1016/j.applthermaleng.2025.128133","url":null,"abstract":"<div><div>Ethanol production has developed rapidly in China, but it faces the issue of high energy consumption. Spray flash evaporation technology was considered a promising method for energy savings in the ethanol production process. In this work, an experimental system for spray flash evaporation was constructed, which used an ethanol–water solution. The spray characteristics and mass transfer performance of the ethanol–water solution were examined under different experimental conditions. The results were shown that the flash evaporation efficiency and the concentration of the distillate were promoted by the increase in the initial concentration, but the flash evaporation efficiency of water in the ethanol–water solution was inhibited. Parameters such as the distillate flow rate, flashing efficiency and distillate concentration were all regarded as increasing functions of the initial temperature. However, compared with the distillate flow rate and flashing efficiency, the increase in the distillate concentration was not significant. The flash evaporation efficiency of low-concentration ethanol–water solutions was made to vary almost linearly with the degrees of superheat. A decrease in distillate flow rate, distillate concentration, and flash evaporation efficiency was caused by an increase in vacuum chamber pressure. A decrease in flash evaporation efficiency and distillate concentration was caused by excessive spray flow rate. The flash evaporation efficiency could be improved by increasing the nozzle diameter from 1.4 mm to 1.8 mm. The purpose of this study was aimed at providing guidance for energy-saving in ethanol production.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128133"},"PeriodicalIF":6.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933654","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":"Thermal load estimation with non-gray radiation and soot for upper stage engine","authors":"Vikrant Sharma,&nbsp;Pradeep Kumar","doi":"10.1016/j.applthermaleng.2025.128093","DOIUrl":"10.1016/j.applthermaleng.2025.128093","url":null,"abstract":"<div><div>The rocket engine is subjected to severe thermal loads due to the extreme temperatures generated by LOX/methane combustion, with both radiative and convective heat fluxes contributing significantly. Convective heat transfer is estimated using a fluid flow and combustion model, while radiative transfer is evaluated through the Spectral Line Weighted-Sum-of-Gray-Gases (SLW) and Planck mean method. Numerical subroutines for both methods have been developed and integrated into a computational fluid dynamics solver for comprehensive analysis. A parametric study is conducted for a methane-fueled upper-stage engine, considering soot volume fractions ranging from <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>8</mn></mrow></msup></mrow></math></span> to <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span>. Species mass fractions and total temperature are obtained via chemical equilibrium calculations. The results reveal that the Planck mean gray model substantially overpredicts the absorbed radiative heat flux, nearly twice that predicted by the SLW method, although both capture consistent overall trends. In the divergent section, radiation-participating gases (<span><math><mo>≈</mo></math></span>99% of the mixture) create an opaque medium, significantly attenuating radiation to the engine wall and limiting its contribution to the total heat load. However, the inclusion of soot at a volume fraction of <span><math><mrow><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mo>−</mo><mn>5</mn></mrow></msup></mrow></math></span> nearly doubles the absorbed radiative flux compared to the purely gaseous case, highlighting its critical role in thermal loading.</div></div>","PeriodicalId":8201,"journal":{"name":"Applied Thermal Engineering","volume":"280 ","pages":"Article 128093"},"PeriodicalIF":6.9,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932419","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}