Transfer Problem Research Articles

Analysis of Optimal Power Flow Using Combined PSO-GSA Technique

Using a hybrid approach that incorporates both particle swarm optimization (PSO) and gravitational search algorithms (GSA), this project aims to find the best way for power systems to distribute their energy. A novel heuristic search optimization technique, the GSA is works on the law of gravity. While this strategy has many advantages, it suffers from sluggish search performance and memory constraints. In order to discover a solution to this problem, the PSO technique was utilized. PSO and GSA, were utilized in this investigation to discover the optimal power flow utilizing a combination of these two methodologies. The suggested optimization method merges the social thinking and local search features of particle swarm optimization with those of the GSA, therefore taking benefit of both algorithms. This study examines and evaluates an optimization technique for the optimal power flow problem, focusing on reducing fuel costs, improving the voltage profile, and minimizing real power losses. The investigation and assessment are conducted on the commonly used IEEE 30-bus test systems. The simulation findings showcase the robust and effective resolution of the optimum power transfer problem through the amalgamation of Particle Swarm Optimization (PSO) and Gravitational Search Algorithm (GSA).

Topology Optimization for Conjugate Heat Transfer Problems Based on the k-omega Turbulence Model

Topology Optimization for Conjugate Heat Transfer Problems Based on the k-omega Turbulence Model

Study on heat transfer of waxy crude oil melting phase change based on a novel model

The study of phase change heat transfer of crude oil melting is important for pre-heating and restarting of pipelines. Combining the characteristics of waxy crude oil characteristics of waxy crude oil melting, a novel mathematical model was established, which can accurately describe the non-linear release of latent heat, liquid-solid interface changes, natural convection, and other key heat transfer problems. In the process of heating and melting, the variation law of the solid-phase interface position in the pipe at different initial solidification states was analyzed. The results showed that in the partially solidified pipeline, the liquid crude oil in the pipeline has a higher temperature at the initial heating stage, and continuously loses heat to the low temperature crude oil, resulting in a decline in the liquid-phase ratio at the initial stage. Because crude oil was affected by different degrees of radial thermal resistance, latent heat release and porous medium characteristics at different positions of the pipeline, the temperature drop curves of the crude oil varies greatly.

Numerical validation of ice formation on a lattice structure evaporator

This paper presents a comparative analysis between experimental and numerical results of the ice formation process on the surface of the evaporator in a Sparkling Water Dispenser. The experimental setup comprises an R290 refrigeration cycle that is fully equipped with thermocouples, pressure transducers, a wattmeter, and a Coriolis-meter. The evaporator, which is specifically designed to enhance the ice formation speed, is situated within a water-filled tank, where the ice formation process takes place. Due to the phase change phenomenon, which involves the interface between two phases moving, solving transient heat transfer problems involving solidifications can be inherently challenging. Analytical solutions are only possible under certain simplified circumstances. In cases where exact solutions are not available, semi-analytic, approximate, and numerical methods can be utilized to address phase-change problems. A numerical model of the solidification process based on the energy equation and conjugate heat transfer was developed using COMSOL Multiphysics. The software was found to be effective in simulating the physical processes associated with heat transfer through conduction and convection, as well as the behaviour of phase change. The results showed a very good agreement between experimental and numerical results.

Impact of heat source on mixed convection hybrid ferrofluid flow across a shrinking inclined plate subject to convective boundary conditions

Hybrid ferrofluids have exhibited enhanced heat transfer results in numerous applications. Industry demands like inclination sensors and solar water heaters give a new insight into heat transfer problems on the angle of inclination problems. Thus, this paper is motivated to analyse the effect of inclination angle towards mixed convection hybrid ferrofluid flow, including heat sources and convective boundary conditions, on a porous shrink surface. By utilising a similarity transformation, the intricate nature of the partial differential equations (PDEs) is simplified, transforming it into a set of ordinary differential equations (ODEs) and numerically solved in the bvp4c (MATLAB). A positive correlation was obtained between the current model and past researchers. Besides that, the increase in nanoparticle volume fraction improved the skin friction by approximately 14.79% and 15.00% for opposing and assisting flow regions, accordingly. Altering the inclination angle positively impacted growth by approximately 3.28% and 0.0068% on the skin friction and the heat transfer rate, accordingly. The inclusion of a heat source reduced the heat transfer rate by approximately 0.20% and 0.19% for both opposing and assisting flow regions, respectively. Meanwhile, a greater rise in heat transfer rate by approximately 174.48% when the Biot number, Bi rose.

Experimental set-up for the validation of phase change models in case of direct and inverse heat transfer problems

Experimental set-up for the validation of phase change models in case of direct and inverse heat transfer problems

Fuzzy Levenberg-Marquardt damping factor update strategy and Tikhonov regularization applied to a coupled conduction-radiation inverse heat transfer problem

The recently proposed Fuzzy Levenberg-Marquardt Damping Factor Updating Strategy (FLM) is used along with Tikhonov Regularization (TR) in order to solve a coupled conduction-radiation function estimation inverse problem. FLM consists of updating the Levenberg-Marquardt (LM) damping factor with the assist of Fuzzy Logic. To test the FLM algorithm combined with TR, a conduction-radiation problem is addressed, and it serves as test bed to the numerical experiments, where the objective is to obtain estimatives of parameters, such as the spatially variable scattering albedo, the thermal conductivity and the optical thickness, simultaneously, which is often performed separately. Two main test cases are presented, one considering only the radiation problem, used as benchmark, in order to investigate noise levels and hyperparameters. The second main test case deals with the coupled conduction-radiation heat transfer problem for different functional forms of the spatially variable scattering albedo. For all presented numerical experiments, good estimates were achieved for the sought functions and parameters. These results demonstrate that the methodology presented in this work, through the combination of the Fuzzy LM dampting factor updating strategy and the Tikhonov regularization scheme, may provide valuable tools for inverse heat transfer problems.

Solution of the Heat and Mass Transfer Problem for Soil Radiant Heating Conditions Using the Error Function

Achieving high yields of agricultural crops requires the ability to predict soil temperature and moisture regimes, taking into account soil heating technology. The object of study is soil heated by a ceiling infrared emitter. The subject of study is one-dimensional non-stationary fields of soil moisture content and temperature. The objective of the study is to predict soil temperature and moisture regimes under radiant heating conditions. Research methods: analytical methods for solving differential equations of heat and mass transfer using the error function. Research results: the top 5 mm layer of milled peat with an initial moisture content of 3.7 kg/kg will reach a final moisture content of 1.0 kg/kg in about 6 hours during infrared drying. As a result of radiant heating, the soil will heat up from an initial temperature of 5 ℃ to a final temperature of 20 ℃ in approximately 3 hours. The analytical solution of the mass transfer differential equation can be used for theoretical studies of drying of capillary-porous materials, for example, to determine the drying period or the thickness of the material layer that will dry to a given final moisture content. The analytical solution of the heat transfer differential equation can be used to control the operating mode of the infrared radiation source, for example, to determine the periods of its operation and switching off in case the soil surface temperature reaches the maximum (critical) value. The mathematical solutions considered in the article do not take into account the cross processes of heat and mass transfer, which is a promising direction for further scientific research.

BASIC PRINCIPLES OF COGNITIVE TERMINOLOGY

The article provides an overview of cognitive research in terminology. The purpose of the research is to analyze the work on the study of the problems of cognitive terminology that arose under the influence of the anthropocentric paradigm, to show the difference between traditional terminology and cognitive terminology, to determine the main provisions of cognitive terminology. The importance of the idea of studying terms from a cognitive point of view can be seen in the following: firstly, the cognitive aspect allows you to study the term from the point of view of cognitive terminology, secondly, cognitive terminology helps to understand the complex and contradictory nature of the term, directs terminologists to study the internal laws of the term, thirdly, cognitive research in terminology promotes the study of a term from a new perspective. The problem of formation, preservation and transfer of professional knowledge from generation to generation through terminological units in the context of the dynamic development of modern science and technology determines the relevance of research work. From a cognitive point of view, terminology is considered as the result of cognitive activity of a specialist, in which professional knowledge is conceptualized and verbalized. The article analyzes the scientific papers that served as the basis for the emergence of cognitive terminology. In these works, we are talking about the theoretical and practical significance of cognitive terminology as cognition and the linguistic picture of the world, the unity of the processes of categorization and naming, discourse and professional discourse, the cognitive-informational nature of the term, everyday and scientific knowledge, professional knowledge.

Telephone follow-up by nurse practitioners of geriatric patients discharged from the emergency department after traumatic injury

IntroductionGeriatric patients discharged from the emergency department (ED) after an injury are at risk for adverse outcomes. Older patients are at a higher risk for sensory impairments and cognitive problems which can make comprehension of discharge instructions more difficult. Moreover, geriatric patients often have limited skills with or access to alternative sources of information, such as hospital web pages or phone applications, which could put them at a higher risk of undertreatment. Implementing telephone follow-up after discharge presents a potential solution to enhance information transfer and address problems related to the injury. MethodsAn exploratory cohort study was conducted in the ED of an inner-city hospital in the Netherlands between 2019-2020. Patients ≥70 years were included if they presented with an injury and were discharged home from the ED. Telephone follow-up was performed by an ED nurse practitioner within 48 hours after discharge to address any problems or questions relating to the injury. Feasibility was assessed by determining whether the intervention could be performed within the allotted time period during normal work hours (1 h per day). The frequency and type of additional advice given, as well as patient satisfaction with the intervention, were documented. Results635 patients were eligible for inclusion, and 266 completed the intervention (median age 77 years; 32 % male). Nurse practitioners were able to complete the intervention on over 90 % of days. A total of 64 % of patients received additional advice during the telephone call, mostly related to pain medication adjustments and instructions to contact their GP. Patient satisfaction with the intervention was high (median score 8/10). ConclusionTelephone follow-up is a feasible intervention that may be able to enhance older patients' comprehension of discharge instructions and help identify new problems after discharge. During the follow-up call, the majority of patients received additional advice, indicating a potential demand for this intervention. The main limitation was that not all eligible patients were approached or did not want to participate in the intervention. Future studies should investigate whether telephone follow-up can effectively reduce adverse events and improve the quality of life for these patients.

СОВЕРШЕНСТВОВАНИЕ РАСЧЕТА ПРОСТРАНСТВЕННЫХ СТЕРЖНЕВЫХ КОНСТРУКЦИЙ ИЗ ПОЛИМЕРНЫХ МАТЕРИАЛОВ С УЧЕТОМ ТЕМПЕРАТУРНОГО ВОЗДЕЙСТВИЯ.

The influence of temperature effects on the technical condition of cross-bar spatial structures (CSRS) made of polymer building materials (PSM) is considered using the example of tubular elements made of polyvinyl chloride (PVC). From numerous scientific studies by various authors, it is known that low and high temperatures significantly affect the mechanical safety of engineering plastics: tensile-compressive strength, bending, loss of stability, torsion, which ultimately reduces the operational reliability and durability of CSRS. The current regulatory and technical construction documentation on loads and impacts provides only climatic temperature impacts. In the documentation for building structures, technological temperature effects do not take into account the time factor. The general solution to the problem of unsteady heat transfer of a cylindrical element is considered in a nonlinear formulation to calculate the two-dimensional temperature field separately for the rod cylindrical element and the node connection in the “cylinder-cylinder” system. Graphic illustrations of the calculations are provided.

Modelling 2-D Heat Transfer Problem for Different Material Combination

The analysis of heat transfer problems can be highly complex due to factors such as temperature, position, and time. Most heat transfers are typically two-dimensional as conduction is often negligible in the third dimension. Two-dimensional heat conduction problems can be solved analytically or numerically. In steady-state conditions, the Laplace equation can be applied to solve two-dimensional heat conduction problems analytically, in which the separation of variables method is used to solve the Laplace equation under fixed boundary conditions to determine the temperature at a specific point. The Laplace equation plays a significant role in the solution of heat transfer problems, as it demonstrates the behavior of linear and non-linear equations in the computational fluid dynamics domain. Despite their inability to provide exact results at any point, numerical methods are superior to analytical methods when handling complex geometries with various boundary conditions. This project involves the development of a computational code using MATLAB to solve two-dimensional steady-state heat conduction problems using Gauss-Seidel iterations. Comparing analytical solutions from Excel with numerical solutions from MATLAB and ANSYS, specifically the developed MATLAB code, revealed an accuracy level of 99.902% for the Laplace equation. An analysis of the produced code from MATLAB found that it could solve two-dimensional steady-state heat conduction across different combinations of materials while allowing users to specify initial and boundary conditions to produce a contour plot similar to ANSYS.

Computer 3D Modeling of the Process of Wastewater Treatment in a Settling Tank

Purpose. Settling tanks are widely used in technological schemes of wastewater treatment. As a rule, horizontal settling tanks are used in practice. However, to increase the efficiency of water treatment in a horizontal settling tank, additional elements can be used, which are placed in different places in the structure. When reconstructing such structures or designing them for new facilities, it is necessary to assess the efficiency of the settling tanks under different operating conditions. To solve this problem, mathematical models play an important role, including conducting physical experiments, which requires considerable time to obtain results. In the case of mathematical modeling of the water treatment process in a sedimentation tank, two problems need to be solved: the hydrodynamic problem and the mass transfer problem. The main purpose of this paper is to develop a 3DCFD model for calculating the impurity concentration field in a sedimentation tank. Methodology. A dynamic multifactorial numerical model was developed for computer calculation of the wastewater treatment process in a settling tank. The hydrodynamics of the wastewater flow in the settling tank was calculated on the basis of a three-dimensional equation for the velocity potential (potential motion model). The calculation of the impurity concentration field in the settling tank was determined by numerical integration of the three-dimensional mass transfer equation. This equation takes into account the non-uniformity of the flow velocity field in the settling tank, the diffusion process, and the gravitational deposition of the impurity in the structure. The numerical integration of the modeled equations was carried out by using finite-difference splitting schemes. Findings. The software implementation of the constructed mathematical model was carried out. The results of a computational experiment to study the process of wastewater treatment in a settling tank with visualization of the calculation results are presented. Originality. A multifactorial three-dimensional CFD model has been developed that allows to quickly assess the efficiency of the settling tank. Practical value. The proposed CFD model can be used in calculations in the design of wastewater treatment systems or to determine the efficiency of wastewater treatment under new operating conditions.

Linear generator for power supply to on-board consumers of high-speed magnetically levitated carriages

Background: Maglev transport is a promising mode of transport that can provide passenger and freight transportation at speeds of up to 400-500 km/h, and in the longer term – up to 1000 km/h. Active research in this area is being conducted in China, Japan, and the USA. Currently, in China and Japan, speeds of 450-500 km/h have been achieved for commercial transportation, and promising programs have been adopted for the construction of high-speed maglev tracks and the creation of rolling stock. At such speeds, one of the pressing problems is the problem of contactless energy transfer for on-board consumers located on the carriage, because it is very difficult to ensure reliable contact current collection at speeds of 450-500 km/h and above.
 Aim: development of the design, calculation and analysis of the characteristics of a linear generator of electrical energy for contactless power transfer to the moving crew of high-speed magnetically levitated transport.
 Materials and methods: to calculate the external magnetic field of the linear generator inductor and the EMF induced in the receiving coil of the crew, methods of electromagnetic field theory and electrical circuit theory were used; calculation algorithms are implemented in the Visual Basic for Applications software environment.
 Results: a design was proposed and the calculation of the external magnetic field of an inductor with transposition of conductors was performed; to increase the EMF induced in the receiving coil of the crew, it is proposed to give the receiving coil a double 8-shape; the most rational inter-circuit distance of the linear generator inductor has been established; the nature of the change in the magnetic flux penetrating the receiving coil when the vehicle moves, and the magnitude of the emf induced in the receiving coil are determined.
 Conclusion: the results can be used in the development of rolling stock for promising high-speed maglev transport systems.

Multi-objective topology optimization of heat transfer surface using level-set method and adaptive mesh refinement in OpenFOAM

The present study proposes a new efficient and robust algorithm for multi-objectives topology optimization of heat transfer surfaces to achieve heat transfer enhancement with a less pressure drop penalty based on a continuous adjoint approach. It is achieved with a customized OpenFOAM solver, which is based on a volume penalization method for solving a steady and laminar flow around iso-thermal solid objects with arbitrary geometries. The fluid-solid interface is captured by a level-set function combined with a newly proposed robust reinitialization scheme ensuring that the interface diffusion is always kept within a single local grid spacing. Adaptive mesh refinement is applied in near-wall regions automatically detected by the level-set function to keep high resolution locally, thereby reduces the overall computational cost for the forward and adjoint analyses. The developed solver is first validated in a drag reduction problem of a flow around a two-dimensional cylinder at the Reynolds numbers of 10 and 40 by comparing reference data. Then, the proposed scheme is extended to heat transfer problems in a two-dimensional flow at the Prandtl number of 0.7 and 6.9. Finally, three-dimensional topology optimization for multi-objective problems is considered for cost functionals with different weights for the total drag and heat transfer. Among various solutions obtained on the Pareto front, 4.0% of heat transfer enhancement with 12.6% drag reduction is achieved at the Reynolds number of 10 and the Prandtl number of 6.9. Moreover, the optimization of a staggered pin-fin array demonstrates that the optimal shapes and arrangement of the fins strongly depend on the number of rows from the inlet. Specifically, the pin-fins in the first and third rows extended in the upstream direction further enhance heat transfer, while the fins in the second row vanish to reduce pressure loss.

Analysis of Heat Transfer Pathways That Affect Mitigation of Cascading Thermal Runaway

As the energy density of systems of lithium-ion batteries increases, and as they are employed in larger-scale energy storage systems, greater attention must be paid to the safety of these systems. Failure of a single cell can trigger thermal runaway processes that cascade through the system, endangering first responders and nearby structures. This cascading failure is driven by heat transfer through the system to vulnerable cells and other combustible materials. To understand how to mitigate thermal runaway, the most important heat transfer pathways must be characterized in terms of their magnitude and time scale.Heat must be removed from cells that have gone into thermal runaway without leading vulnerable cells into thermal runaway. The onset of thermal runaway typically occurs around 200oC and depends on the heating time (i.e. cells heated slowly in an oven will begin thermal runaway around 150oC). The objective then becomes avoiding these thermal runaway temperatures for surrounding cells while dissipating any heat released from an initial thermal runaway event.While there are many individual parameters that describe the cells and system, in this work it will be seen that the thermal analysis can be reduced to a collection of non-dimensional parameters. These parameters describe heat conduction within the cell, heat capacity of a cell, total heat released by a cell in thermal runaway, conductive heat transfer to adjacent cells and surroundings, and convective heat transfer to surrounding gases.A simple cell-to-cell propagation scenario is constructed to separately investigate the heat transfer parameter space. In this model scenario, an “initiating” cell is assumed to have just completed thermal runaway and exhausted all its reactants. This heats that cell to a high temperature that depends on the cell chemistry and state of charge. Adjacent to this “initiating” cell is the “target” cell. We use canonical heat transfer problems to identify a set of parameters that determine the temperature of the “target” cell. The attached figure depicts the prominent heat transfer pathways for a notional propagation scenario. The parameters space of interest includes the thermal resistance (left), the heat capacity of the involved materials (center), and heat losses to the ambient surroundings (right). The relative time scales of these heat transfer rates determine the propagation speed and ultimately the point at which cascading thermal runaway is mitigated.The thermal parameter space is interrogated by solving the transient heat transfer problem with a combination of analytical techniques, a quasi-1D finite volume software, and 3D finite element software. The maximum temperature reached by the edge of the target cell is recorded and used as the criteria for the boundary between propagation and mitigation. The scaling relationships developed through this analysis can provide thermal engineers and system designers with a framework for predicting the safety of battery pack designs in the context of cascading thermal runaway. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525 SAND2023-02583A Figure 1

Combination of Karhunen-Loève and intrusive polynomial chaos for uncertainty quantification of thermomagnetic convection problem with stochastic boundary condition

Uncertainty propagation analysis plays a crucial role in understanding the impact of variations in initial condition, boundary condition, and fluid physical properties on simulation results for thermomagnetic convection heat transfer problems. To effectively analyze the uncertainty problem of thermomagnetic convection caused by random temperature fluctuations, a novel and comprehensive computational framework based on intrusive polynomial chaos approach was proposed in this paper. Our proposed approach aims to represent random temperature boundaries using Karhunen-Loève expansion (KLE) and stochastic output response using polynomial chaos expansion (PCE). In addition, we use spectral projection method to transform the stochastic control equation into a group of deterministic control equations. We obtained the uncertainty characteristics of the stochastic output response by solving each polynomial chaos basis. Compared with Monte Carlo simulation (MCS), our approach accurately and efficiently predicts the uncertainty characteristics of thermomagnetic convection problems under stochastic temperature boundary conditions while significantly reducing computational resources.

Investigation of the thermal analysis of a wavy fin with radiation impact: an application of extreme learning machine

The combined impact of radiation and convection on the heat transfer of a wavy fin is scrutinized in the present analysis. The novelty of this research work is that it proposes a deterministic machine learning model known as an extreme learning machine to address the heat transfer problem of a wavy fin. The effect of radiation on convective heat transfer and the Rosseland approximation for the radiation heat exchange have been considered in the investigation. The nonlinear ordinary differential equation (ODE) is converted to its nondimensional form using the appropriate dimensionless variables. Runge-Kutta-Fehlberg's fourth-fifth order technique (RKF 45) is used to solve the nondimensional ODE numerically. The roles of convection-conduction, radiation-conduction, thermal conductivity, and radiation parameters have been discussed for satisfying a prescribed temperature distribution in rectangular and wavy fins with graphical visualization. A rise in convection-conduction and radiation-conduction variables decreased the thermal distribution of both the wavy fin and rectangular fin. Further, ANSYS simulation analyzes the variation of temperature and total heat flux in both rectangular and wavy fins. The study demonstrates the effectiveness of the model selected through the obtained results, which indicate the potential of the regression model for providing an accurate prediction.

An Analysis of Solutions to the Frame Consistency Problem in Video style Transfer based on GAN

Video style transfer has emerged as a significant area within the realm of neural style transfer, holding promise for diverse applications. In this context, GANs have gained traction for their advantages in addressing temporal consistency concerns. This paper explores various strategies to manage frame consistency within GAN-based video-style conversion. It delves into techniques such as Recurrent Neural Networks (RNNs), 3D convolutions, inter-frame continuity in the discriminator, and time loss functions. The research highlights key studies that employ RNNs to complement GAN-based frameworks for improved temporal consistency. The study also evaluates a range of other approaches, such as introducing inter-frame continuity in the discriminator and applying time loss functions to minimize visual discrepancies. Through this analysis, the paper contributes insights into the evolving landscape of video style transfer techniques, guiding researchers towards effective strategies for achieving frame consistency and advancing the field.

THE TRAUTMAN PROBLEM OF INFORMATION TRANSFER, THE PROBLEM OF ENERGY TRANSFER BY GRAVITATIONAL WAVES AND THE STATUS OF THE POINCARE GAUGE THEORY OF GRAVITY

The transfer of information is one of the problems of the propagation of gravitational waves in connection with the prospect of the possible use of high-frequency gravitational waves for the creation of space communications. The requirements for information transfer are formulated in the form of the Trautman problem, which defines the conditions under which gravitational waves invariantly transfer the information contained in them. The second problem of the propagation of gravitational waves is the problem of energy-momentum transfer, which is not solved in general relativity, but can be solved in the punch of the gauge theory of gravity, for which the “criterion of strong localization of the energy-momentum of the gravitational field” is formulated. The features of two approaches in the Poincare gauge theory of gravity are discussed.