Heat Transfer Process Research Articles

Cooling Performance Experiment and Simulation Investigation of Flow Boiling Heat Transfer for Wire Rods during Quenching in Molten Salt Mixtures

When the wire is cooled in the salt bath, since the wire temperature far exceeds the boiling point of the molten salt, accurately modeling the heat transfer process in molten salt quenching is difficult. Therefore, for investigating the cooling mechanism and improving the mechanical properties of wire rods, quenching experiments are conducted on specimens (92Si) at various molten salt (a 1:1 mixture of NaNO3‐KNO3) temperatures using a salt bath furnace. Cooling curves are measured, and thus the real boiling heat transfer coefficient (HTC) at the metal–salt interface is calculated using a validated in‐house‐programmed inverse heat transfer algorithm based on experimental data. By integrating the experimentally determined boiling HTC with the convective HTC obtained from a salt bath simulation, a mathematical model of superposition flow boiling heat transfer is developed to predict the heat transfer characteristics, wire cooling behavior, and phase‐transformation processes within the salt bath, which is also an innovation point of this article. The model effectively captures the actual heat transfer behavior during the early stages of salt bath quenching. The model is further used to evaluate the optimal molten salt temperature for quenching in a modified salt bath system with a flow rate of 60 m3 h−1.

Extra Tree Regressor and Tree-structured Parzen Estimator based Machine Learning Model for Predicting Nanofluid’s Nusselt Number

Abstract Boiling is a very effective method of heat transfer process, which is characterized by phase change, due to phase change high transfer rates of heat occur at much smaller temperature differences between the heated surface and the fluid. By introducing nanofluids, which is a dispersion of nanoparticles in basic fluids when incorporated in flow boiling systems, it can be convenient to enhance energy efficiency and ultimately reduce world energy consumption. The intent of this research is to evaluate the practicality of using machine learning (ML) models as a substitute for Computational Fluid Dynamics (CFD) in heat transfer simulation. This research uses Extra Tree Regressor (ETR) with Tree-structured Parzen Estimator algorithm (TPE) to estimate the Nusselt number in water-based nanofluids that consist of Al2O3 and TiO2, nanoparticles. ETR is tree based machine learning algorithm and TPE is used to tune the hyper parameter of ETR. The ETR-TPE model is used to establish a correlation among nanoparticle parameters such as type of nanofluids, Reynolds number, size, volume percentage and Nusselt number. Various statistical measures and scatter plots are used to compare and estimate the performance of the proposed ETR-TPE model. The model has excellent predictive accuracy, as shown by a R² value of 0.980381 and 0.986313 for Al2O3 and TiO2 respectively. The Root Mean Square Error (RMSE) is computed and found to be 12.96 and 10.01 for Al2O3 and TiO2 respectively. The proposed ETR-TPE model demonstrates a strong correlation in accurately estimating the Nusselt Number based on experimental data.

The Effect of Mold Flux Wetting Conditions with Varying Crucible Materials on Crystallization.

Understanding mold flux crystallization is essential for assessing heat transfer during steel casting. The complexity of the mold gap presents challenges in identifying the optimal testing method and nucleation type. This study investigates how variations in wetting properties influence nucleation dynamics, in particular the wetting behaviors of mold flux in platinum and graphite crucibles and how they affect crystallization temperatures and solidification mechanisms. Advanced analytical techniques, including confocal laser scanning microscopy (CLSM), and differential scanning calorimetry (DSC) were employed to analyze nucleation under different conditions, with calibration using synthetic slag, Li2SO4, and thermodynamic equilibrium simulations. The findings highlight the crucial role of crucible materials in modifying nucleation energy barriers and undercooling requirements. These insights enhance the understanding of mold flux behavior, contributing to the refinement of testing methodologies and the optimization of heat transfer and solidification processes in continuous casting.

Large-Scale Synthesis of Perovskite Quantum Dots and Their Application to Inkjet-Printed Highly Stable Microarray.

Perovskite quantum dots (PeQDs) with a pure emission and solution-processable path are highly desirable for color conversion materials to achieve full color and high-resolution display. Yet, operational stability and precise deposition methods remain critical factors that limit their applications. Additionally, the traditional high-temperature synthesis suffers from a short reaction time window, making it difficult to realize large-scale synthesis for practical applications. Here, an in situ reacted multiple-anchoring ligands strategy is reported to effectively extend the high-temperature reaction time for synthesizing PeQDs from 5 to 200 s, endowing the large-scale synthesis in a sufficient time window for mass and heat transfer processes. This strategy simultaneously improves the photo-thermal stability of PeQD patterned films. Uniform and high-resolution microarrays are fabricated by inkjet printing through exquisite control of solvent engineering and substrate optimization, exhibiting reversible fluorescence when suffering high temperatures up to 100 °C. This approach enables large-area (10 × 10 cm2) red and green dual-color patterned microarrays, covering a color gamut of 128% NTSC and 96% BT. 2020. These advancements mark a significant step toward scalable, high-performance PeQD displays, highlighting great potential for next-generation display technologies.

SPH Simulation of Gear Meshing with Lubricating Fluid–Solid Coupling and Heat-Transfer Process

This study employs the meshfree Smoothed Particle Hydrodynamics (SPH) method to simulate the fluid–solid coupling process of gear meshing rotation with lubricating oil or oil jet lubrication fluids, considering the heat-transfer process under preset initial temperature conditions. While traditional grid methods face challenges in simulating the dynamic interaction between gear-meshing rotation and lubricating fluids, such as time-dependent contact in fluid–solid coupling and heat transfer, difficulties in handling meshing gaps, and the complexity of dynamic mesh setup, our approach leverages the unique advantages of meshless methods. In the established fluid–solid–heat coupling model, gears are considered as rigid bodies, and both fluids and gears are discretized into SPH particles, achieving fluid–solid coupling through the interaction between fluid particles and solid SPH particles. The model considers three cooling scenarios: oil pool cooling, oil jet cooling, and combined cooling. Simulation results show that oil pool cooling is more effective than oil jet cooling, but oil jet cooling can achieve localized spot cooling. The model exhibits good computational stability and efficiency in simulating the fluid–solid coupling and heat-transfer processes of gear rotation, oil jetting, and oil pool fluids. This study provides an effective numerical simulation method for gear lubrication cooling and has significant application potential for simulating complex scenarios such as gear operation and oil pool sloshing in coal mining machine arms. Compared to previous SPH work, this study couples a thermodynamic model in the simulation, thus enabling the modeling of fluid–thermal–solid coupled processes.

Walters B’ hybrid nanofluid flow with Marangoni convection

Walters B’ hybrid nanofluid flow with Marangoni convection

Study on the dynamic heat transfer role of vertical greening in building microclimate based on multi-objective coupling

Global warming and continuous urbanization have gradually exacerbated building energy consumption and the urban heat island effect, seriously constraining urban development and residents' quality of life. Based on this, this study focuses on row-type buildings as the research object. It constructs and couples microclimate and air conditioning energy consumption models of the building perimeter using ENVI-met, EnergyPlus, and Fluent software. The study aims to discuss the microclimate impacts of the vertical greening system and systematically analyze the integrated role of vertical greening in the dynamic heat transfer process. The study results show that vertical greening significantly reduces the temperature around the target building. The maximum temperature decreases by 2.65 °C during the daytime, while the minimum temperature slightly increases by 0.95 °C at night. Additionally, the average heat island intensity decreases from 1.15 to 0.3 °C. Meanwhile, vertical greening significantly reduced the air conditioning energy consumption of the target building, decreasing power consumption by 531 W. In addition, due to air conditioning heat transfer, the temperature and wind speed around the target building increased, causing the average heat island intensity to rise from 0.3 to 1.52 °C. The average heat island intensity of the target building increased from 0.3 to 1.52 °C. This study not only reveals the heat transfer mechanism and energy-saving effects of vertical greening under different environmental conditions but also provides a scientific basis for the application of vertical greening technology in the construction field.

Thermite-for-demise (T4D): experiments and numerical modelling on solar array drive mechanism mock-ups containing thermite in an arc-heated wind tunnel

Abstract The ESA-TRP SPADEXO project investigated the use of thermites to provide additional enthalpy to a spacecraft re-entering towards the Earth, with the objective of limiting its casualty risk on ground. Steel mock-ups inspired by the geometry of solar array drive mechanisms were filled with thermite and placed in DLR’s L2K arc-heated hypersonic wind tunnel. In each of these samples, a set of thermocouples was installed to monitor ignition and propagation of the heat generated by the reaction. One of the thermocouples was placed in a hole machined inside the mock-up wall to monitor temperature evolution in proximity of the pyrotechnic charge, without the risk of losing the sensor due to the ignition of the thermite. The main objective of these tests was to study the dependence of the heat transferred from the internal charge to the surrounding structure from the filling level. Results showed that higher thermite filling resulted in higher transferred enthalpy. In the presence of a large thermite amount, the reaction led to the formation of a dense liquid drop close to the side wall, causing significant heat transfer towards the wall of the mock-up. Tests were rebuilt using the SCARAB re-entry software, extended with a dedicated model to represent the ignition of an internal charge. Ignition and heat transfer were adequately described by the model in most of the test configurations. Specific parameter tuning was needed for the highest filling factor tested in this work, highlighting the influence of reaction products internal dynamics on the heat transfer processes.

Research Results of Heat and Mass Transfer in Conditions of Weak Aerodynamic Coupling with Pulsating Ventilation Mode

Introduction. The issue of heat dissipation in metallurgy is significant due to potential hazards to personnel and the environment. Effective control and management of thermal processes require additional measures and can prevent fires, explosions, and personnel injuries as well as it is a key factor in ensuring the safety and reliability of metallurgical equipment. Metallurgical processes often involve high temperatures, but control over them is necessary for successful steel melting and processing. Current methods of heat transfer control (aeration, general exchange and local ventilation) do not always effectively reduce heat loads to acceptable levels. The choice of a pulsating ventilation mode for increasing the efficiency of heat transfer control is due to two main reasons: low air flow rates in large metallurgical production facilities, and the presence of numerous hard-to-reach areas with heat-generating equipment. The aim of this research is to investigate heat and mass transfer processes in areas with weak aerodynamic coupling with pulsating ventilation mode.Materials and Methods. To achieve this goal, a method of physical modeling was employed to collect statistical data. Heat and mass transfer were evaluated by measuring temperature changes over time at various points in the model niche under different ventilation conditions (stationary and. pulsating). System analysis was then applied to process the collected data.Research Results. It was found that pulsating air movement had a positive effect on heat and mass transfer in poorly ventilated spaces inside the laboratory setup. The degree of efficiency of this effect was determined, and it was found that the use of pulsating ventilation slowed down the increase in temperature in the center of the space by 3.8 times compared to the use of general forced ventilation.Discussion and Conclusion. The data obtained under the simulated conditions of the aforementioned type of production provide a foundation for developing a more specific methodology to counteract the negative effects of heat radiation. This methodology could significantly enhance safety by improving the removal of excess heat in low-aerodynamic areas of mining and metallurgical workshops.

Impact of Nonlinear Motion on Convective Heat Transfer Induced by Oscillating Thermal Waves in the Presence of Heat Source and Sink

The perspective of this paper is to provide detailed understanding about convective heat transfer influenced by oscillating thermal waves in the presence of heat source and sink. The study begins by formulating the continuity equation, momentum equation and heat equation to describe the complex, nonlinear dynamics of fluid flow, heat transfer and vorticity. These nonlinear equations are then converted into a dimensionless form using specific scaling variables to facilitate the analysis. The dimensionless equations are further transformed into steady and unsteady forms to account for different thermal and flow conditions. A primitive variable approach is employed and the finite difference method is used to obtain numerical results. Computational solutions are generated using FORTRAN Laher-90 and including graphs and tables, are created using Tecplot-360 to illustrate the effects of time-dependent vorticity and oscillating thermal waves on the system in the form of transient shear stress [Formula: see text] and transient heat transfer [Formula: see text]. The findings provide new insights into the interactions between vorticity, nonlinear fluid motion and thermal oscillations, offering valuable contributions to the understanding and optimization of convective heat transfer processes. The findings indicate that temperature distributions and velocity profiles increased for different values of heat source parameter [Formula: see text], while both are showed opposite behavior for different values of heat sink parameter [Formula: see text] in steady state. For unsteady state, heat source parameter at [Formula: see text] and heat sink parameter at value [Formula: see text], the amplitude of the wave of transient shear stress [Formula: see text] increased and then showed a slightly disturbance in the phase angle for further values, similarly for the heat source parameter at value of [Formula: see text] and heat sink parameter at value [Formula: see text], the magnitude of the wave of transient heat transfer [Formula: see text] showed increment.

Transient Heat Transfer Modeling of SERF Co-Magnetometer Atomic Ensemble Based on the Thermoelectric Analogy Method

Bias instability is one of the most critical factors in the performance of spin-exchange relaxation-free (SERF) co-magnetometers. Previous studies on SERF co-magnetometers have shown that changes in the atomic ensemble temperature can lead to variations in the alkali metal atom density, which in turn affect the optical rotation angle and light shift, ultimately influencing the system’s stability. Building on this understanding, this paper introduces the thermoelectric analogy method for the first time in the transient heat transfer analysis of SERF co-magnetometer atomic ensembles. Using this method, the primary factors affecting the atomic ensemble temperature in a SERF co-magnetometer were analyzed, and transient heat transfer models were established for the following processes: the interaction between the non-magnetic electric heating system and the atomic ensemble temperature, laser heating of the atomic ensemble by the optical system, and the effect of environmental temperature changes on the non-magnetic electric heating system. These models were experimentally validated through active temperature variation experiments. The experimental results show that the proposed transient heat transfer models accurately describe the related heat transfer processes of the atomic ensemble, with model fitting accuracy exceeding 98%. This lays a solid foundation for the high-precision closed-loop control of the atomic ensemble temperature in SERF co-magnetometers and provides valuable insights for the structural design and engineering applications of SERF co-magnetometers.

Theoretical analysis of CNTs blood-based nanofluid over a bidirectional expanding surface: Magnetic field, thermal radiation, and viscous dissipation effects

This theoretical study examines the effects of thermal radiation, viscous dissipation, and a magnetic field effect on a nanofluid that contains carbon nanotubes in blood and moves over a two-way expanding surface. We consider both the stretching and contracting directions when examining the bidirectional nature of the expanding surface. We define the problem’s governing equations, which include energy and momentum, and transform them into a set of ordinary differential equations using suitable similarity transformations. We semi-numerically solve the resulting equations using HAM methods and the BVPh. 2.0 program. We also discuss the consequences of heat radiation and viscosity dissipation in the nanofluid. The Rosseland approximation models the effect of thermal radiation, while the incorporation of fluid’s internal friction represents viscous dissipation. This research aims to investigate the combined effects of various parameters, such as thermal radiation, Eckert number, nanoparticle volume fraction, couple stress parameter, power law index, magnetic field, and Prandtl number, on the heat, flow, and transfer properties of single-walled carbon nanotube (SWCNT), multi-walled carbon nanotube (MWCNT), and blood-based nanofluids. A fascinating field of study, this study will reveal useful details about the possible uses of carbon nanotube blood-based nanofluids across bidirectional expanding surfaces in drug delivery systems, heat transfer processes, and biomedical engineering. Blood-based nanofluids can benefit from the inclusion of carbon nanotubes to improve fluid behavior and thermal conductivity, which is crucial for a number of industrial and medicinal applications.

Heat Transfer in Unsteady Flow of Third-Grade Fluid Over a Flat Rigid Plate with Porous Medium

This study investigates the heat transfer characteristics of an unsteady flow of a third-grade fluid over a flat rigid plate embedded in a porous medium. The governing equations, including the momentum and energy equations, are derived based on the assumptions of incompressible fluid and negligible body forces. Analytical methods are employed to solve the coupled non-linear equations. The effects of various parameters, such as the porosity of the medium, thermal conductivity, and the non-Newtonian fluid properties, on the velocity, temperature profiles, and skin friction are discussed extensively. The results provide insights into optimizing heat transfer processes in engineering applications, including polymer processing and geothermal systems.

Experimental and Theoretical Investigation into the Thermal Conductivity and Heating-Softening Bending of Glass-Fiber-Reinforced Polypropylene Rebars

Thermoplastic fiber-reinforced polymer (FRP) reinforcement has a significant advantage over traditional thermosetting FRP reinforcements in that it can be bent on site by heating-softening processing. However, current experimental and theoretical research on the thermal conductivity and heating-softening processing characteristics of thermoplastic FRP reinforcements is quite insufficient. Through heating-softening processing tests, numerical simulation, and theoretical calculation, this study investigated the heating-softening processing time of a thermoplastic glass-fiber-reinforced polypropylene (GFRPP) reinforcement. In the heat transfer process, thermal conductivity is typically treated as a constant. However, the experimental results indicated that the thermal conductivity/diffusivity coefficient of the GFRPP reinforcement was temperature-dependent. On this basis, an equivalent modified thermal diffusivity coefficient of glass fiber was proposed to account for the time-temperature-dependent heat conductivity of the GFRPP reinforcement, utilizing a series model. Utilizing the modified thermal diffusivity coefficient, the simulation model presented a heating-softening processing time that coincided well with the experimental results, with a mean ratio of 1.005 and a coefficient of variation of 0.033. Moreover, based on an equivalent homogeneous circular cross-section assumption of the GFRPP reinforcement, an analytical solution to the heat conduction equation was derived. Combining the experimental and simulation results, a semi-analytical and semi-empirical calculation model was also proposed for predicting the heating-softening processing time of a GFRPP reinforcement with a silicone tube cover. The model’s calculated results align with the simulation trends, with an average deviation of 1.0% and a coefficient of variation of 0.026, demonstrating strong potential for engineering applications.

Volume calculation and heat transfer performance simulation of a helical tube with cryogenic helium under intermittent flow condition

The intermittent flow cold storage heat exchanger is one of the most important components of the pulse tube expansion refrigerator based on the reverse Brayton cycle. In the experimental system, the volume and heat transfer of the helical tube play a decisive role in the stable operation of the whole experimental system. However, there are few studies on heat transfer in a helical tube under helium working medium and intermittent flow conditions. In this paper, a process and method for calculating the volume of a helical tube are proposed based on the gas vessel dynamics model. Subsequently, a three-dimensional simulation model of the helical tube was established to analyze the heat transfer process of cryogenic helium within the tube. The simulations revealed that the temperature of helium in the tube decreases to the wall temperature and does not change when the helical angle exceeds 720°. Moreover, within the mass flow rate range of 1.6 g/s to 3.2 g/s, an increase in the mass flow rate was found to enhance the heat transfer performance of the helical tube. This study provides a reference for the selection and application of a helical tube under intermittent flow conditions and also contributes to the experimental research of inter-wall heat exchanger and pulse tube expansion refrigerators.

THE IMPACT OF HIGH TEMPERATURES ON THE LOAD-BEARING CAPACITY OF WOODEN STRUCTURES

Problem statement. Wooden structures are widely used in construction both in Ukraine and globally. They offer numerous advantages over other building materials, which is particularly valued in the construction of residential and public buildings. However, wood is a combustible material, and in the presence of a high-temperature source, it can sustain burning. Recent scientific studies have increasingly focused on the destructive processes occurring in wood under the influence of high temperatures, particularly the burnout of surface layers of the structure to a critical level, which may lead to collapse. However, insufficient attention has been paid to other destructive changes that can reduce the integrity and load-bearing capacity of wood without visible signs of burning. The complexity and interdependence of different stages of the wood combustion process make it difficult, and sometimes impossible, to accurately assess its fire resistance and develop effective methods to improve the fire resistance of wooden structures. Currently, there are no practical and tested methods for assessing the fire resistance of such structures. Given this, there is a need for further theoretical research into the processes of heating and burning of wood during fires. To better understand the complex combustion process, it is advisable to divide it into characteristic stages, which can significantly influence the assessment of the structure's fire resistance. Purpose of the article to analyze the impact of high temperatures on the load-bearing capacity of wooden structures, particularly in fire conditions. The article examines destructive processes occurring in wood during heating, which lead to a reduction in its strength even without visible signs of burning. The article also emphasizes the need for further theoretical studies of heat and mass transfer processes to assess the fire resistance of wooden structures. Conclusion. Wooden structures have many advantages, but their fire resistance remains a challenge due to the combustibility of wood. A significant threat is posed not only by burning but also by destructive processes that can weaken the structures without visible signs of ignition. The complexity of the combustion process complicates the development of reliable fire resistance assessment methods, thus necessitating further research. The proposed mathematical models can help better understand the processes of heat and mass transfer and improve methods for assessing the fire resistance of wooden structures.

Formation of the Microclimate of Residential Premises during Heating with a Radiant-Convective Heating Device

This article examines the peculiarities of microclimate formation when using radiant-convective heating device - radiator. The main purpose of the work is to determine the advantages and disadvantages of radiator heating in residential premises, to assess the influence of window sizes, room dimensions and the device on the formation of the microclimate in the room. The study includes the analysis of temperature and velocity fields in three representative rooms of different sizes and configurations. The authors identify the disadvantages of current heating systems associated with the uneven temperature distribution across the height of the room and the formation of zones of reduced comfort near the windows. The work examines three typical rooms for which mathematical modeling of thermal processes is carried out using differential equations to describe the processes of heat and mass transfer. The main attention is paid to the influence of window sizes, room dimensions and heating devices on the microclimate. The authors note that radiators do not always cover the entire width of windows, which leads to the formation of cold zones at their edges, the penetration of cold air deeper into the room and the formation of discomfort zones inside the room. The simulation results show that the indoor air parameters comply with GOST standards, however, the subjective comfort of residents may decrease due to uneven temperature distribution. In conclusion, it is concluded that it is necessary to develop new types of heating devices that will more effectively cope with the task of maintaining a comfortable microclimate and will eliminate the negative impact of cold air penetration through window openings on comfort.

Investigation of Flow Boiling Heat Transfer Mechanisms in Channels with Complex Wall Configurations

Flow boiling has numerous applications in many daily life and industrial fields due to its high heat transfer efficiency. By using the Lattice Boltzmann Method (LBM) with the pseudopotential model, coupled with the finite difference method to solve the temperature field, the flow boiling process of water in a 2D horizontal channel with complex configurations is simulated. The study investigates the impact of different factors such as wall configurations and fluid velocity on the flow and heat transfer processes. The results show that the more cavities and finer pillars in the wall structure, the higher the heat transfer efficiency. Increasing the flow velocity effectively promotes bubble detachment and enhances heat transfer efficiency. This study provides insights for channels configuration designs.

Numerical Simulation of the Gas Flow of Combustion Products from Ignition in a Solid Rocket Motor Under Conditions of Propellant Creep

The development of modern solid rocket technology with high-performance and high-loading ratio propellants places higher requirements on the safety and stability of the solid rocket motor. The propellant of the solid rocket motor will creep during long-term vertical storage, which may adversely affect its regular operation. The ignition transient process is a critical phase in the operation of solid rocket motors. The Abaqus v.2022 finite element simulation software is used to analyze the ignition transient under propellant creep conditions and obtain the deformed combustion chamber profile. Then, we use a high-precision finite volume solver developed independently to simulate the flow field during the ignition process. In the simulation, we adopt the surface temperature of the propellant column reaching the ignition threshold as the ignition criterion, considering the heat transfer process of the propellant column instead of using the near-wall gas temperature to obtain the set temperature. Simulation results under different creep conditions reveal that the deformation of the propellant grains progressively intensifies as the solid rocket motor’s storage duration increases. This leads to a delayed initial ignition time of the propellant, an advancement of the overall ignition transient process, and an increased pressurization rate during ignition, which can affect the structure and regular operation of the motor. The research results provide design guidance and theoretical support for the design and life prediction of solid rocket motors.

Molecular Dynamics Simulations of CeO2 Nano-Fuel: Thermodynamic and Kinetic Properties

This study explores the thermodynamic and kinetic properties of CeO2 nano-fuels, with a particular focus on the influence of nanoparticle additives on the diffusion and thermal conductivity of C14-based fuel systems. Using molecular dynamics simulations and the COMPASS force field, we model the interactions between C14 molecules and CeO2 nanoparticles, varying nanoparticle size and concentration. Our results reveal that the inclusion of CeO2 nanoparticles leads to significant enhancements in both thermal conductivity (increasing by 9.8–23.6%) and diffusion coefficients (increasing by approximately 140%) within the 20 °C to 100 °C temperature range. These improvements are attributed to the interactions between nanoparticles and fuel molecules, which facilitate more efficient energy and mass transport. Notably, nanoparticles with smaller sizes (0.2 nm and 0.5 nm) exhibit more pronounced effects on both the thermodynamic and kinetic properties than larger nanoparticle analogs (20 nm and 50 nm). The study also highlights the temperature-dependent nature of these properties, demonstrating that nanoparticle additives enhance the fuel’s thermal stability and diffusion behavior, particularly at elevated temperatures. This work provides valuable insights into the optimization of nano-fuel systems, with potential applications in enhancing the performance and efficiency of diesel combustion and heat transfer processes.