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This paper aims to carry out a thermal-hydraulic simulation model for pump and hydraulic system to predict the temperature increasing and pump performance. Based on the model, how to alleviate the temperature is introduced. Besides, the optimization of piston is carried out.

This paper analyzes the heat generation in lubricating interfaces of the pump with energy conversion theory. The heat transfer inside the pump is analyzed with the control volume method. The simulation model is constructed in AMESim because of its operating friendly nature. The experiment is carried out to prove the validity and accuracy of the simulation model.

Temperature has less effect on the mechanical loss of pump. However, it has a great impact on volumetric efficiency. To reduce the temperature on the piston surface, the size of the piston should be optimized.

This paper fulfills a novel thermal-hydraulic model to evaluate the temperature of the pump. Based on the model, the performance of the pump is determined and optimization is carried out.

The objective of the present work is to simulate the nuclear coupled thermal–hydraulic fast transient case studies for a vertically up-flowing supercritical pressure water channel of circular cross section. The emphasis is on analyzing the phenomenon of the deterioration in heat transfer (DHT) inside the channel subjected to sharp pressure variations.

The thermal–hydraulic model, THRUST, is integrated with the neutron point kinetic (NPK) solver to account for the non-linear interactions between the thermal–hydraulic and neutronic temperature and density reactivity feedback effects. The model implemented and studied accounts for the time-dependent reactor power and is used to analyze various steady-state and flow-induced transient case studies (time-dependent and step change in exit pressure).

There is good agreement in the predicted behavior of the supercritical water pressure system with that of the available experimental data for the steady-state case. The event of DHT in the second transient case (step decrease in exit pressure) is found to be more severe than that of exponential pressure decrease.

This study evaluated a novel implementation of the thermal–hydraulic model, THRUST, integrated with NPKs applied to supercritical pressure water systems for predicting DHT.

The purpose of this paper is to investigate the impact of semi-circular zigzag-channel printed circuit heat exchanger (PCHE) design parameters on heat transfer and pressure drop of flows under high Reynolds numbers and provide new thermal-hydraulic correlations relevant to conditions encountered in natural gas processing plants.

The correlations were developed using three-dimensional steady-state computational fluid dynamics simulations with varying semicircular channel diameter (from 1 to 5 mm), zigzag angle (from 15° to 45°) and Reynolds number (from 40,000 to 100,000). The simulation results were validated by comparison with experimental results and existing correlations.

The results revealed that the thermal-hydraulic performance was mostly affected by the zigzag angle, followed by the ratio of the zigzag channel length to the hydraulic diameter. Overall, smaller zigzag angles favored heat transfer intensification while keeping reasonably low pressure drops.

This study is, to date, the only one providing thermal-hydraulic correlations for PCHEs with zigzag channels under high Reynolds numbers. Besides, the broad range of parameters considered makes the proposed correlations valuable PCHE design tools.

Simulation and analysis of a real main steam line break transient at the Thermal Power Plant Drmno are presented. The main events of the transient were the closure of isolation valves in front of a high pressure turbine, an opening of a by‐pass line, and subsequent pipe break in front of isolation valves. Intensive pressure waves were generated and they propagated through the pipe network of the steam line, causing high fluid dynamic forces on the structure. The transient has been simulated by the computer code TEA‐01, based on the Method Of Characteristics with three characteristic directions. Several main steam line boundary conditions have been modelled and verified. Numerical results are compared with plant data logger records. Simulation has been performed for various scenarios in order to investigate the plant behaviour sensitivity on the boundary conditions. The phenomenology of the pressure waves propagation and the influence of the boundary conditions on these processes are described in detail, as well as fluid dynamic forces during the closure of isolation valves and subsequent pipe break in a section of the steam line in the vicinity of the pipe break.

This study aims to examine both the population balance approach based on the MUltiple SIze Group (MUSIG) model and the average bubble number density transport equation (ABND) model for 3D, low pressure, gas‐liquid, subcooled boiling, vertical flows. The purpose is to assess the ability of both models to predict the radial profile of void fraction, bubble Sauter mean diameter and interfacial area concentration which characterise subcooled boiling.

Improvement in the ABND model to simulate gas‐liquid bubbly flows with heat transfer was achieved by combining the condensation expression with the gaseous mass transport equation within the CFD commercial code CFX4.4.

Overall, both the ABND model and the MUSIG model provided good results in terms of the above‐mentioned criteria when compared against experimental measurements. However, the ABND model was found to have limitations in predicting high‐subcooled boiling flows due to the lack of bubble size resolution to adequately capture the effect of condensation over a range of bubbles sizes.

It is shown that the ABND model provides an economic alternative to the MUSIG model in terms of complexity and computational time, as long as one is aware of the limitations in simulating high‐subcooling flow regimes.

Spiral-wound heat exchangers (SWHEs) are widely used in different industries. In special applications, such as cryogenic (HEs), fluid properties may significantly depend on fluid temperature. This paper aims to present an analytical method for design and rating of SWHEs considering variable fluid properties with consistent shell geometry and single-phase fluid.

To consider variations of fluid properties, the HE is divided into identical segments, and the fluid properties are assumed to be constant in each segment. Validation of the analytical method is accomplished by using three-dimensional numerical simulation with shear stress transport k-ω model, and the numerical model is verified by using the experimental data. Moreover, the HE cost is selected as the main criterion in obtaining the proper design, and the most affordable geometry is selected as the proper design.

The accuracy of different heat transfer and pressure drop correlations is investigated by comparing the analytical and numerical results. The average errors in the calculation of effectiveness, shell-side pressure drop and tube-side pressure drop using the analytical method are 2.1%, 13.9% and 13.3%, respectively. Moreover, the effect of five main geometrical parameters on the SWHE cost is investigated. The results indicate that the effect of longitudinal pitch ratio on the SWHE cost can be neglected, whereas other geometrical parameters have a significant impact on the total cost of the SWHE.

This work contains a versatile and low-cost analytical method to design and rating the SWHEs considering the variable fluid property with consistent shell geometry. The previous studies have introduced complex methods and have not considered the consistency of shell geometry.

The application of dry-type transformers is growing in the market because the technology is non-flammable, safer and environmentally friendly. However, the unit dimensions are normally larger and material costs become higher, as no oil is present for dielectric insulation or cooling. At designing stage, a transformer thermal model used for predicting temperature rise is fundamental and the modelling of cooling system is particularly important. This paper aims to describe a thermal model used to compute dry transformers with different cooling system configurations.

The paper introduces a fast-calculating thermal and pressure network model for dry-transformer cooling systems, preliminarily verified by analytical methods and advanced CFD simulations, and finally validated with experimental results.

This paper provides an overview of the network model of dry-transformer cooling system, describing its topology and its main variants including natural or forced ventilation, with or without cooling duct in the core, enclosure with roof and floor ventilation openings and air barriers. Finally, it presents a formulation for the new heat exchanger element.

The network approach presented in this paper allows to model efficiently the cooling system of dry-type transformers. This model is based on physical principles rather than empirical assessments that are valid only for specific transformer technologies. In comparison with CFD simulation approach, the network model runs much faster and the accuracies still fall in acceptable range; therefore, one is able to utilize this method in optimization procedures included in transformer design systems.

To provide a validation of a three‐dimensional (3D) macroscopic model for superconductors comparing numerical to experimental AC losses of a BSCCO‐2223 tape subject to an orthogonal magnetic field and a transport current.

We solve in 3D geometries the eddy current problem in presence of superconductors, represented by a power‐law characteristic rewritten into a variational form. An integral formulation of the magneto‐quasistatic Maxwell's equations is used. The solution of the problem is found by an unconstrained minimization of a suitable functional. The numerical results on AC losses computation are compared to experimental data.

The agreement between numerical and experimental data is good in a wide range of currents and magnetic fields.

The magnetic field is assumed to be orthogonal to the tape. Different incidence angles should be taken into account.

It is possible to extend the range of validity of the engineering formulae for AC losses used in the work.

The paper provides a validation of a numerical code against experimental results: this is always challenging in the field of applied superconductivity.

This study aims to computational numerical simulations to clarify and explore the influences of periodic cellular lattice (PCL) morphological parameters – such as lattice structure topology (simple cubic, body-centered cubic, z-reinforced body-centered cubic [BCCZ], face-centered cubic and z-reinforced face-centered cubic [FCCZ] lattice structures) and porosity value ( ) – on the thermal-hydraulic characteristics of the novel trussed fin-and-elliptical tube heat exchanger (FETHX), which has led to a deeper understanding of the superior heat transfer enhancement ability of the PCL structure.

A three-dimensional computational fluid dynamics (CFD) model is proposed in this paper to provide better understanding of the fluid flow and heat transfer behavior of the PCL structures in the trussed FETHXs associated with different structure topologies and high-porosities. The flow governing equations of the trussed FETHX are solved by the CFD software ANSYS CFX® and use the Menter SST turbulence model to accurately predict flow characteristics in the fluid flow region.

The thermal-hydraulic performance benchmarks analysis – such as field synergy performance and performance evaluation criteria – conducted during this research successfully identified demonstrates that if the high porosity of all PCL structures decrease to 92%, the best thermal-hydraulic performance is provided. Overall, according to the obtained outcomes, the trussed FETHX with the advantages of using BCCZ lattice structure at 92% porosity presents good thermal-hydraulic performance enhancement among all the investigated PCL structures.

To the best of the authors’ knowledge, this paper is one of the first in the literature that provides thorough thermal-hydraulic characteristics of a novel trussed FETHX with high-porosity PCL structures.