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parameter study OF LAMINAR FLOW AND HEAT TRANSFER IN AN INTERRUPTED MICROCHANNEL HEAT SINK WITH RIBS

HEAT TRANSFER RESEARCH 2021年第2期52卷 13-27页

作者： Wang, Wei Shuai, Yong Su, Wentao Li, Bingxi Tan, Yufei Sunden, Bengt Harbin Inst Technol Sch Energy Sci & Engn Harbin 150001 Peoples R China Harbin Inst Technol Sch Environm Harbin 150001 Peoples R China Liaoning Shihua Univ Coll Petr Engn Fushun 113001 Peoples R China Lund Univ Dept Energy Sci S-22100 Lund Sweden

The enhanced heat transfer mechanism and parameter optimization of an interrupted microchannel heat sink with rectangular ribs (IMCHS-R) was numerically studied for Reynolds number ranging from 100 to 900, using ANSYS Fluent. Interrupted microchannel heat sinks with different kinds of rectangular ribs having different width, length, and locations were compared with a straight microchannel and microchannel interrupted chambers. The results indicated that the heat transfer and flow resistance were mainly strengthened at the sudden converging area and narrow channels, and the secondary flow area did not show a positive effect on heat transfer. The IMCHS-R with W-2/W-1 = 0.3 and L-2/L-1 = 0.7 presented the best behavior from both PEC and Stot-ave at Re = 500-700. The heat transfer performance can be improved 2.0 times compared to the straight microchannel heat sink and the PEC can reach a value larger than 1.5. However, the rib location has a little effect on the enhanced heat transfer performances.

关键词： interrupted microchannel heat sink numerical simulation parameter study entropy analysis overall heat transfer performance

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parameter study of a kinetic-frictional continuum model of a disk impeller high-shear granulator

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POWDER TECHNOLOGY 2013年 238卷 20-26页

作者： Abrahamsson, P. J. Bjorn, I. Niklasson Rasmuson, A. Chalmers Univ Technol Dept Chem Engn SE-41296 Gothenburg Sweden Astra Zeneca Pharmaceut Dev R&D Molndal SE-43183 Molndal Sweden

A disk impeller high shear granulator was modeled with a kinetic-frictional continuum model. A parameter study was made and the parameterization of the equations was assessed to investigate if the model is suited for modeling high shear granulation. A dry granule mixing was studied and the parameters investigated were the particle diameter, the angle of internal friction, the particle-particle restitution coefficient, the particle density, the particle velocity boundary condition, the packing limit and the numerical parameter frictional packing limit. All the particle related parameters can be expected to change during a granulation. The flow field prediction of the model is in agreement with the behavior described by Knight et al. (2001), showing a rigid torus. This is in contrast to a discrete element model simulation that predicts inner rotation within the torus (Gantt and Gatzke 2006). The general flow field of this system is fairly insensitive to all parameter changes, except a change to no slip boundary condition for the particle phase, even though several parameters significantly affect the solid phase viscosity. The model was used to predict the change in impeller torque when going from mixing a dry powder to a wet system. It is shown that the models have some potential for qualitative descriptions of the wet state. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Kinetic Theory of Granular Flow Frictional model High shear granulation parameter study

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parameter study of electrospinning of polyamide-6

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EUROPEAN POLYMER JOURNAL 2008年第10期44卷 3067-3079页

作者： Heikkila, Pirjo Harlin, Ali Tampere Univ Technol FIN-33101 Tampere Finland

Importance of different solution and process parameters were evaluated in multi-nozzle electrospinning of polyamide-6. We were interested in how those parameters affect firstly on fibre diameters and fibre diameter distribution and secondly on production rate and disturbances of the process. The trial series was planned using orthogonal experimental design. Altogether eight parameters having three or two levels each were chosen for this study. The chosen solution parameters were polymer grade, viscosity of solution, salt content and solvent grade and process parameters, voltage, distance, nozzle size and feeding pressure of solution. This study was performed using continuous electrospinning equipment consisting of multiple nozzles and horizontal electric field. Literature findings about the influences of certain variables are often contradictory. These contradictions and their possible causes were discussed. (c) 2008 Elsevier Ltd. All rights reserved.

关键词： Electrospinning parameter study Polyamide Nanofibres Morphology Productivity

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parameter study and multi-objective optimization for crashworthiness of a B-type metro train

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PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART F-JOURNAL OF RAIL AND RAPID TRANSIT 2022年第1期236卷 91-108页

作者： Liu, Yanwen Yang, Bing Xiao, Shou-ne Zhu, Tao Yang, Guangwu Xiu, Ruixian Southwest Jiaotong Univ State Key Lab Tract Power Chengdu 610031 Peoples R China Changchun Railway Vehicles Co Ltd Basic R&D Dept Natl Railway Passenger Car Engn Res Ctr Jilin Peoples R China Changchun Normal Univ Coll Engn Jilin Peoples R China

A train's crashworthiness responses are directly affected by the vehicle weight M, train collision speed V, and empty stroke D. This study investigated the influences of M, V, and D on train crashworthiness. A one-dimensional multi-body dynamics model for a B-type metro train was created and verified. Approximate models were established for the total compression displacement (TS) and overall average collision deceleration (TMA) based on M, V, and D, and a novel method was proposed for quickly predicting the output response of a train's crashworthiness. The effects of the various parameters on TS and TMA were investigated, and a multi-objective optimization for minimizing TS and TMA was conducted. The results indicated that V has the greatest influence on TS and TMA, followed by M, and then D;M has a positive effect on TS and negative effect on TMA, whereas D has a negative effect on both TS and TMA;V has a positive effect on TS, but for TMA, the effect changes from positive to negative when V increases to 23 km/h. The optimized metro train has higher integrity in the passenger living space and a lower train collision average deceleration, and the crashworthiness is significantly improved.

关键词： Crashworthiness parameter study design of experiment approximate model multi-objective optimization

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parameter study of Glucose-Sensitive Hydrogel: Effect of Immobilized Glucose Oxidase on Diffusion and Deformation

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SOFT MATERIALS 2013年第1期11卷 69-74页

作者： Luo, Rongmo Li, Hua Nanyang Technol Univ Sch Mech & Aerosp Engn Singapore 639798 Singapore

A comprehensive parameter study is carried out in this paper for analysis of the influence of the immobilized glucose oxidase (GOx) and catalase on the equilibrium response of a glucose-sensitive hydrogel, based on the multi-effect-coupling glucose-stimulus (MECglu) model developed by the present authors. For the practical physiological glucose concentration ranging from 0 to 16.5mM (300mg/ml), the studied parameters distribute over both the hydrogel and surrounding solution domains, and include the reacting and diffusive species concentrations, the average pH, and mechanical deformation of the glucose-sensitive hydrogel. The parameter study achieves the optimal values of the GOx and catalase loaded in the insulin delivery system that is based on the glucose-sensitive hydrogel.

关键词： Deformation Diffusion Glucose oxidase Glucose-sensitive hydrogel parameter study

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parameter study of extrusion simulation and grain structure prediction for 6xxx alloys with varied Fe content

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MATERIALS TODAY COMMUNICATIONS 2024年 38卷

作者： Hovden, S. Kronsteiner, J. Arnoldt, A. Horwatitsch, D. Kunschert, G. Oesterreicher, J. A. AIT Austrian Inst Technol LKR Light Met Technol A-5282 Ranshofen Austria

Increasing the recycled content is key to improve the sustainability of aluminum wrought alloys. However, Al scrap is often contaminated with Fe. Thus, coping with elevated Fe contents of wrought alloys is essential, but more Fe leads to more intermetallic phases, which impact extrudability and Peripheral Coarse Grain (PCG) formation. Coarse grains at the surfaces of aluminum extrudates can have a major detrimental influence on ductility, corrosion, and fatigue behavior. Therefore, it is desired to minimize the formation of PCG while keeping up the productivity of the process. PCG formation is dependent on local state variables such as temperature, strain, and strain rate, and second phase particles. In this work, we study extrusion of the aluminum alloys EN AW-6060, EN AW-6005A and EN AW-6082 with standard and increased Fe contents (0.2 and 0.7 wt. %). A parameter study of extrusion simulations was performed using the commercial extrusion software Altair (R) InspireTM Extrude Metal. Ram speed, billet temperature, and tooling temperature were varied, for a total of 245 simulations for each alloy. In order to tackle the large number of simulations and to increase computational efficiency, the evolution of microstructure was calculated after the extrusion simulation. For this purpose, the local state variables temperature, strain, and strain rate, were taken from a plane cut of the profile. These parameters along with experimentally determined initial microstructural properties (before extrusion) were used as input for a stand-alone microstructure simulation code. The final grain size distribution output of the microstructure simulations was compared to the microstructure obtained after extrusion experiments. In this way, our work furthers the understanding of the relationships between alloy composition, process parameters, and PCG formation.

关键词： Microstructure modeling Metal extrusion FEM parameter study PCG

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parameter study of sound energy distribution in cuboid extra-large spaces

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建筑模拟（英文版） 2019年第5期12卷 835-846页

作者： Chao Wang Hui Ma Jian Kang School of Architecture Tianjin University Tianjin 300072 China School of Architecture Tianjin University Tianjin 300072 China UCL Institute for Environmental Design and Engineering The Bartlett University Colege London (UCL) Central House 14 Upper Woburn Place London WC1H 0NN UK

The aim of this paper is to explore the sound energy distribution in cuboid extra-large spaces. The surface absorption and height are studied as the parameters using the image method. Air absorption is also discussed in this paper. The results show that the difficulty of reducing the noise increases with the increasing volume in extra-large spaces. Even if the ratio between the equivalent absorption area and the total surface is kept constant, the efficiency of noise reduction decreases by approximately 21％ in this study. The absorption areas on the floor and the walls have a better performance on noise reduction than that on the ceiling. When the initial height of an extra-large space with general ratio of three dimensions is continuously halved, the variation in the noise level is close to a fixed value, and when the initial height continuously doubled, the noise level decreased approximately exponentialy. The predicted difference between with and without consideration of air absorption increases linearly with the source-receiver distance.

关键词： extra-large space energy distribution image method parameter study sound absorption

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parameter study on performance of building cooling by night-time ventilation

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RENEWABLE ENERGY 2008年第12期33卷 2589-2598页

作者： Artmann, N. Manz, H. Heiselberg, P. Empa Swiss Fed Labs Mat Testing & Res Lab Bldg Technol CH-8600 Dubendorf Switzerland Univ Aalborg Dept Civil Engn Hybrid Ventilat Ctr DK-9000 Aalborg Denmark

Especially for commercial buildings in moderate climates, night-time ventilation seems to be a simple and energy-efficient approach to improve thermal comfort in summer. However, due to uncertainties in the prediction of thermal comfort in buildings with night-time ventilation, architects and engineers are still hesitant to apply this technique. In order to reduce the uncertainties, the most important parameters affecting night ventilation performance need to be identified. A typical office room was therefore modelled using a building energy simulation programme (HELIOS), and the effect of different parameters such as building construction, heat gains, air change rates heat transfer coefficients and, climatic conditions including annual variations on the number of overheating degree hours (operative room temperature >26 degrees C) was evaluated. Climatic conditions and air flow rate during night-time ventilation were found to have the largest effect. But thermal mass and internal heat gains also have a significant effect on cooling performance and the achievable level of thermal comfort. Using this modelling approach, significant sensitivity to heat transfer was found only for total heat transfer coefficients below about 4 W/m(2) K. (c) 2008 Elsevier Ltd. All rights reserved.

关键词： passive cooling night-time ventilation parameter study thermal mass heat transfer climate

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parameter study for critical heat flux under external reactor vessel cooling condition based on a mechanism model

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APPLIED THERMAL ENGINEERING 2024年 238卷

作者： Wang, Gang Kuang, Bo Zhao, Yu Han, Shilei Liu, Pengfei Hou, Jieming Shanghai Jiao Tong Univ Sch Mech Engn Dongchuan Rd 800 Shanghai 200240 Peoples R China Dongchuan Rd 800 Shanghai 200240 Peoples R China

External reactor vessel cooling has been adopted an important method to implement In Vessel Retention severe accident mitigation strategy for many advanced passive pressurized water reactors. Critical heat flux is one of the important criteria to evaluate the success or failure of this strategy. The uncertainty of engineering factors in practical design and operation conditions may make influence on critical heat flux more or less. In this paper, a parameter study for critical heat flux was carried out based on a new critical heat flux mechanism model. This mechanism model is developed based on the mechanism of liquid film dryout, and the predicted results of this model are in good agreement with the experimental results. Five important parameters, namely, coolant subcooling degree, geometry of lower head, system pressure, flow rate and heating power shape are analyzed based on this mechanism model. The results of parameter study show that the decrease of inlet coolant temperature and lower head radius are beneficial to the increase of critical heat flux. And the critical heat flux increases with the increase of system pressure. While the change of flow rate and heating power shape have little effect on critical heat flux. Under the condition of same circumference, the critical heat flux of spherical lower head is higher than that of elliptical lower head in the middle and low inclination angle region, while the trend is opposite in high inclination angle region, but not significant.

关键词： External reactor vessel cooling Critical heat flux parameter study Mechanism model

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parameter study of Some Key Structures for Cylinder Head

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Journal of Beijing Institute of Technology 2004年第2期13卷 183-186页

作者：张儒华左正兴曹丽亚廖日东 School of Mechanical and Vehicular Engineering Beijing Institute of TechnologyBeijing100081China

Using the method of the parameter study, some important dimensions of the cylinder head of an internal-combustion engine are analyzed. Under the mechanical load, the variational rules of the von Mises maximum stress on cylinder head are obtained, which are influenced by the thickness of the floor plate, head plate, jobbing sheet, standing partition board, and side plate of inlet port and exhaust port. A hypothesis is verified that there is an ideal matching point among those above-mentioned main parameters. The quantificational proportion relations, between these key structural parameters and von Mises maximum stress of cylinder head, can provide a good help for the cylinder head's structural design.

关键词： cylinder head parameter study finite element

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