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Study on the Optimal Velocity of Horizontal Air Jet of a Range Hood System

TRANSACTIONS OF THE KOREAN SOCIETY OF MECHANICAL ENGINEERS B 2025年第1期49卷 25-32页

作者： Kim, Myoung Soo Choi, Hyoung Gwon Kim, Sang Gyu Donggang Univ Dept AI convergence Mech Engn Gwangju South Korea Seoul Natl Univ Sci & Tech Dept Mech & Automot Engn Seoul South Korea Samsung SDI Syst Verificat Grp Youngin Si South Korea

We have investigated on the determination of an optimal horizontal air jet velocity of a range hood system by using a segregated finite element method to conduct three dimensional numerical simulations. The horizontal air jet plays a role of air curtain to isolate a heat generated by a cooking range. Therefore, it can efficiently pump out the isolated heat and contaminant air preventing them from being convected into a living space. simple algorithm was employed to find steady solutions for turbulent flows and k-omega two-equation model was used for turbulence modeling. Present numerical simulations show that the air jet of the present range hood system generates coanda effect isolating the contaminated air in a certain region to pump it out whereas the jet pushes back the contaminated air into a living room as its velocity increases competition of the those two mechanism. Both streamlines and temperature contours are displayed to

关键词： Optimal Jet Velocity Air Curtain Range Hood System Finite Element Method simple algorithm

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Application of IDEAL algorithm based on the collocated unstructured grid for incompressible flows

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COMPUTATIONAL GEOSCIENCES 2024年第5期28卷 907-923页

作者： Chen, Yujie Ling, Kong Zhang, Xiaoyu Xiang, Yue Sun, Dongliang Yu, Bo Zhang, Wei Tao, Wenquan Beijing Inst Petrochem Technol Sch Mech Engn Beijing 102617 Peoples R China Xi An Jiao Tong Univ Sch Energy & Power Engn Key Lab Thermo Fluid Sci & Engn Minist Educ Xian 710049 Peoples R China China Univ Petr East China Coll New Energy Qingdao 266580 Peoples R China Tsinghua Univ Sichuan Energy Internet Res Inst Chengdu 610000 Sichuan Peoples R China

The inner doubly iterative efficient algorithm (IDEAL), an advanced fully implicit algorithm for solving the pressure-velocity coupling problem, lacks a comprehensive implementation procedure on commonly used collocated unstructured grids. Therefore, this study provides a thorough demonstration of the fundamental principles, solving procedures, discretizations of momentum and pressure equations, Rhie-Chow interpolation implementation, mass continuity processing, and boundary condition treatment associated with the IDEAL algorithm on a collocated unstructured grid. Additionally, a comparative analysis between the semi-implicit method for pressure-linked equations (simple) and the IDEAL algorithm is conducted concerning computational efficiency under different grid types and flow conditions. The results indicate a significantly higher computational efficiency achieved by the IDEAL algorithm across all tested cases, attributed to its ability to overcome two fundamental assumptions inherent in the simple algorithm. The average acceleration ratio for these cases is approximately 3.13 (tsimple/tIDEAL). This study serves as a valuable reference for the further development and application of the IDEAL algorithm in solving flow problems with complex irregular domains discretized by unstructured grids.

关键词： IDEAL algorithm Collocated unstructured grid simple algorithm

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Three-dimensional numerical analysis of the impact of the orientation of partially inclined baffles on the combined mass and heat transfer by a turbulent convective airflow

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INTERNATIONAL JOURNAL OF ENERGY AND ENVIRONMENTAL ENGINEERING 2023年第1期14卷 79-94页

作者： Salhi, Jamal-Eddine Zarrouk, Tarik Hmidi, Nassreddine Salhi, Merzouki Salhi, Najim Chennaif, Mohammed Fac Sci Equipe Sci Mat Lab LPTPME Dept Phys Energies Nouvelles & Applicat Mohammed 1er Oujda 60000 Morocco First Mohammed Univ Fac Sci Oujda 60000 Morocco Univ Mohammed 1st Lab Elect Engn & Maintenance LEEM High Sch Technol Oujda Morocco

This paper performed a three-dimensional numerical analysis of the flow structure and heat transfer enhancement of turbulent airflow through a rectangular channel (without baffles, with baffles). Two partially inclined baffles with different orientations are mounted on the bottom and top walls of the channel. The location of the baffles in the direction of flow through the channel of a heat exchanger is of great importance. It depends mainly on the geometrical parameters and the orientation of the baffles. Hence, our study focused on analyzing the effects of the baffles on the thermal-hydraulic behavior in the exchanger by choosing a flat baffle and four configurations of different orientations. Numerical results are presented in terms of axial velocity U, isotherms (T), turbulent kinetic energy (k), amount of heat dissipated by the channel surfaces (Q), average Nusselt number (Nu), friction factor (f), and thermal performance factor (n). The results show that the insertion of the partially inclined baffles into the channel causes the generation of vortices in the upstream and downstream areas of the baffle location point. Thus the mixing phenomenon occurs, which induces an increase in the heat transfer rate and generates a pressure drop simultaneously. Furthermore, the analysis of the results shows that compared to the smooth case (without baffles), the thermal performance factor (eta) is significantly higher in the four configurations with baffles. Thus, for the different cases studied: (2);(3);(4);(5) and (6), the factor (eta) is equal to 2.18;2.16;2.19;2.27;and 2.25, respectively, for a Reynolds number equal to 87,300. The results also indicate that the transmitted relative heat quantities are equal to 116.08, 113.93, 118.2, 121.71, and 109.39%, respectively, for the same cases considered. Therefore, the configuration corresponding to case (5) performs better in heat transfer than the others. Finally, new correlations for predicting friction factor and Nusselt n

关键词： Heat transfer Numerical analysis Turbulent flow Heat exchangers simple algorithm Computational Fluid Dynamics

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Three-dimensional optimization of a heat sink performance using the combined active and passive methods

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INTERNATIONAL JOURNAL OF ENERGY AND ENVIRONMENTAL ENGINEERING 2023年第2期14卷 229-241页

作者： Salhi, Jamal-Eddine Zarrouk, Tarik Chennaif, Mohammed Benaichi, Mohammed Salhi, Merzouki Salhi, Najim Mohammed 1er Univ Fac Sci Dept Phys Equipe Sci Mat Energies Nouvelles & ApplicatLab Oujda 60000 Morocco Ecole Hautes Etud Ingn CREHEIO Ctr Rech Oujda 60000 Morocco Univ Mohammed 1st Oujda Morocco

The present study aims to investigate the effects of the presence of vortex generators in the cooling fluid flow of a microchannel heat sink and to seek to optimize its performance in terms of heat transfer. In addition, the cooling fluid used is a pure water solution in the presence of aluminum oxide (Al2O3) nanoparticles. The numerical simulation is performed for different cases. Each case is characterized by the rate of the volume fraction of aluminum (Al2O3) in the presence of the base fluid (pure water). Four cases were studied in which the rate of the volume fraction of aluminum (Al2O3) suspended in the base fluid was chosen equal to 1%, 2%, 3%, and 4%, respectively. The heat sink is a microchannel, and the numerical simulations are performed for a Reynolds number in the range (600, 1400). A finite volume scheme resolves the system of differential equations governing the physical problem according to the imposed boundary conditions. The problem of pressure-velocity coupling, imposed by the presence of pressure by its gradient in the equations of the algebraic system to be solved, is solved by using the semi-implicit method for pressure-linked equation (simple) algorithm. The different thermal factors: the Nusselt number, the friction factor, and the thermal performance enhancement factor, and the two physical fields: the velocity and the temperature field, have been analyzed. The results obtained show that, for Re = 600, the value of Nu increased with increasing concentrations of 5.68, 8.16, 10.08, and 11.66 for a concentration equal to 1%, 2%, 3%, and 4%, respectively. The results also show that playing a vortex generator with a constant concentration equal to 2% could further improve the thermal performance improvement factor from 25 to 67%. Accordingly, the configuration corresponding to Case 2 performs better in heat transfer than the others. Finally, new correlations to predict the friction factor, Colburn j-factor, and Nusselt number as a Reynolds number

关键词： CFD simple algorithm Nanofluid Al2O3 Heat transfer Nusselt number Colburn coefficient

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A segregated reduced-order model of a pressure-based solver for turbulent compressible flows

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ADVANCED MODELING AND SIMULATION IN ENGINEERING SCIENCES 2025年第1期12卷 1-21页

作者： Zancanaro, Matteo Ngan, Valentin Nkana Stabile, Giovanni Rozza, Gianluigi mathLab Math Area Via Bonomea 265 I-34136 Trieste Italy St Anna Sch Adv Studies BioRobot Inst Viale Rinaldo Piaggio 34 I-56025 Pisa Italy

This article provides a reduced-order modelling framework for turbulent compressible flows discretized by the use of finite volume approaches. The basic idea behind this work is the construction of a reduced-order model capable of providing closely accurate solutions with respect to the high fidelity flow fields. Full-order solutions are often obtained through the use of segregated solvers (solution variables are solved one after another), employing slightly modified conservation laws so that they can be decoupled and then solved one at a time. Classical reduction architectures, on the contrary, rely on the Galerkin projection of a complete Navier-Stokes system to be projected all at once, causing a mild discrepancy with the high order solutions. This article relies on segregated reduced-order algorithms for the resolution of turbulent and compressible flows in the context of physical and geometrical parameters. At the full-order level turbulence is modeled using an eddy viscosity approach. Since there is a variety of different turbulence models for the approximation of this supplementary viscosity, one of the aims of this work is to provide a reduced-order model which is independent on this selection. This goal is reached by the application of hybrid methods where Navier-Stokes equations are projected in a standard way while the viscosity field is approximated by the use of data-driven interpolation methods or by the evaluation of a properly trained neural network. By exploiting the aforementioned expedients it is possible to predict accurate solutions with respect to the full-order problems characterized by high Reynolds numbers and elevated Mach numbers.

关键词： Compressible flows Reduced-order model simple algorithm Turbulence Neural networks

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SPARK: Implicit Time-Accurate algorithm for All-Speed Viscous Flows

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AIAA JOURNAL 2022年第7期60卷 4384-4398页

作者： Yin, Jiangli Rajagopalan, R. Ganesh Iowa State Univ Dept Aerosp Engn Ames IA 50011 USA

A new pressure-based finite volume algorithm is developed for simulating all-speed viscous flows. In this algorithm, the semidiscretized transport equations are integrated in the framework of stiffly accurate diagonally implicit Runge-Kutta methods. At each stage of time integration, the density-pressure-velocity coupling is fully solved, and mass conservation is ensured. The algorithm is verified and validated for several canonical cases over a wide range of freestream Mach number, from incompressible to supersonic flow. The performance and accuracy of the proposed algorithm are benchmarked against established methods for simulating unsteady flow, namely, simple and simpleR.

关键词： Three Dimensional Turbulent Flow Freestream Mach Number Runge Kutta Methods Strouhal Number simple algorithm Velocity Profiles Continuity Equation High Performance Computing Navier Stokes Equations Prandtl Number

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A novel efficient segregated pressure-based algorithm for steady-state incompressible flow

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NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS 2022年第1-2期82卷 18-40页

作者： Deng, Yangyu Zhang, Di Liu, Yakun Fu, Xuemin Wu, Jian Dalian Univ Technol Fac Infrastruct Engn Sch Hydraul Engn Dalian 116024 Liaodong Peoples R China

In order to enhance the calculation efficiency of steady-state incompressible fluid flow, based on the existing IDEAL (i.e. the inner doubly iterative efficient algorithm for linked equations) algorithm, a novel segregated pressure-based algorithm (named as IDEALC) has been developed in this paper. The novel algorithm inherits the superiorities of the original IDEAL algorithm and at the same time improves its potential shortcomings. The specific promotions of the IDEALC algorithm consist of three aspects, including the first approximation of the simple algorithm, the approach to solving the momentum equation and the second approximation of the simple algorithm. Detailed comparisons between the IDEAL and the IDEALC algorithms are carried out by three numerical experiments on structured collocated grids. The numerical results demonstrate that the IDEALC algorithm can accurately predict the information of the flow field and has substantial advantages over the IDEAL algorithm in terms of the efficiency because of the consistent property of the former. The superiority of the IDEALC algorithm over the IDEAL algorithm is especially remarkable when the time step multiplier gets a moderate value.

关键词： Calculation efficiency IDEAL IDEALC incompressible flow segregated pressure-based algorithm simple algorithm

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Numerical study and optimization of important parameters of non-Newtonian nanofluid turbulent flow in a channel with triangular vortex generators using artificial neural network

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ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS 2022年 139卷 94-108页

作者： Pan, Kejia Ibrahim, Muhammad Saeed, Tareq Ibrahim, Syed Shah, Murad Ali Cent South Univ Sch Math & Stat Changsha 410083 Peoples R China CECOS Univ IT & Emerging Sci Dept Basic Sci & Humanities Peshawar Pakistan King Abdulaziz Univ Fac Sci Dept Math Nonlinear Anal & Appl Math NAAM Res Grp POB 80203 Jeddah 21589 Saudi Arabia

The current research investigated the turbulent flow field as well as heat transfer rate (HTR) of the non-Newtonian H2O-Al2O3-carboxymethyl (CMC) in some channel having vortex generators (VGs). The partial differential equations were solved using the finite volume approach and the simple algorithm. The results also revealed that the VG depth change, which was in a few millimeters range, had no considerable impacts on the Nu as well as pressure decrease. In addition, the rise of Re (higher turbulent flow) remarkably increased HTR. Furthermore, due to the formation of vortex movements, local Nu variations revealed a significant rise near the considered VG. With the increase of the VG attack angle, there was a sudden the fluid flow change in the VG zone, resulting a larger DP, especially for the angle of attack of 60 degrees For the 60 degrees attack angle, a number of vortexes were formed behind the VGs, resulting a sudden variation of velocity on the contact surface of the VG. The greatest Nusselt number was 51.321, and the maximum pressure drop was 94993, according to the artificial neural network findings. As a consequence of the Pareto findings, there is a greater pressure decrease when there are more Nusselt.

关键词： Triangular vortex generator Non-Newtonian nanofluid simple algorithm Turbulent flow Mean Nusselt number, Artificial neural network

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Parameter identification of small distributed hydro generators during excitation system start-up

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IET GENERATION TRANSMISSION & DISTRIBUTION 2022年第15期16卷 3119-3127页

作者： Arastou, Alireza Rabieyan, Hadi Karrari, Hesam Karrari, Mehdi Amirkabir Univ Technol Elect Engn Dept 350 Hafez AveValiasr Sq Tehran Iran

Concerning the penetration of renewable energy resources into the power grid, investigation of the power system dynamics to meet the power demand and maintain stability has gathered momentum recently. On the other hand, evaluating the generator parameters in the distributed generation (DG) units as a subsystem of a large-scale power grid is crucial for control and stability analysis purposes. To this aim, a simple and efficacious algorithm to identify the operational parameters of synchronous generators (SGs) in small hydro DGs is proposed here. The required data for the SG identification using the recommended approach is gathered during excitation system start-up while the DG is disconnected from the grid. Using the proposed test procedure, the adverse impact of magnetic saturation on estimation results can be avoided. Furthermore, a straightforward parameter estimation (PE) procedure is established here to obtain the intended parameters from the recorded data. Finally, the proposed method was applied to a 10 MW hydro DG, and the results are discussed.

关键词： efficacious algorithm parameter estimation hydroelectric generators power demand distributed hydro generators power grids generator parameters power system dynamics test procedure recommended approach operational parameters large-scale power grid renewable energy resources parameter identification SG identification excitation system simple algorithm distributed power generation intended parameters straightforward parameter estimation procedure distributed generation units hydro DGs synchronous generators 10 MW hydro DG

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Analysis of the thermohydrodynamic behavior of a cooling system equipped with adjustable fins crossed by the turbulent flow of air in forced convection

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INTERNATIONAL JOURNAL OF ENERGY AND ENVIRONMENTAL ENGINEERING 2022年第3期13卷 1039-1051页

作者： Salhi, Jamal-Eddine Salhi, Merzouki Amghar, Kamal Zarrouk, Tarik Salhi, Najim First Mohammed Univ Fac Sci Lab Mech & Energy LME Oujda 60000 Morocco Abdelmalek Essaadi Univ Natl Sch Appl Sci BP 03 Ajdir Al Hoceima Morocco

The present study focused on researching a technique that can make a cooling system more efficient in terms of heat transfer. To achieve this, it is possible to modify the thermal conductivity of its cooling fluid or the structure of its flow. In this study, we have opted for the second technique. To do this, we sought to create singularities in the flow by inserting vertical and rotating baffles around the vertical. The study field is a channel of rectangular section, placed horizontally, and crossed by the incompressible and turbulent flow of a fluid (air) in forced convection. Geometrically, the physical problem describes mathematically. A system of hyperbolic equations governs it;Navier-Stokes equations derive from the laws of conservation of mass and momentum and the state's law that derives from the principle of conservation of energy. A finite volume scheme ensures the discretization of the governing equations and the numerical analysis's boundary conditions. The turbulence is modeled using the standard k-e model, while the pressure-velocity coupling problem solves by applying the simple algorithm. The proposed numerical computational model validates by comparing the computed results with those of literature correlations. The model was then applied to practical cases where a Reynolds number in the range (12,000, 16,000) has chosen. The orientation angle (theta) of the baffles is chosen equal to (0 degrees, 5 degrees, 7 degrees, 13 degrees, 15 degrees) with a different orientation direction. The calculated results are presented in map form for the different physical fields (of axial velocity, temperature) or in graphical form for the different factors and coefficients (friction factor, amount of heat removal, average Nusselt numbers, and thermal performance factor). The results obtained show that the system is made more efficient with a thermohydrodynamic behavior that varies significantly with the baffles' orientation. The heat transfer rate increased, and th

关键词： Heat transfer Fins Turbulent flow Nusselt numbers simple algorithm Friction factor

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