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Influence of Filling Ratio and Working fluid Thermal Properties on Starting up and Heat Transferring Performance of Closed Loop Plate Oscillating Heat Pipe with Parallel Channels

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Journal of Thermal Science 2017年第1期26卷 73-81页

作者： SHI Weixiu PAN Lisheng School of Environment and Energy Engineering Beijing University of Civil Engineering and Architecture Beijing Key Lab of Heating Gas SupplyVentilating and Air Conditioning Engineering State Key Laboratory of High-temperature Gas Dynamics Institute of MechanicsChinese Academy of Sciences

Using ethanol or acetone as the working fluid, the performance of starting up and heat transfer of closed-loop plate oscillating heat pipe with parallel channels(POHP-PC) were experimentally investigated by varying filling ratio, inclination, working fluids and heating power. The performance of the tested pulsating heat pipe was mainly evaluated by thermal resistance and wall temperature. Heating copper block and cold water bath were adopted in the experimental investigations. It was found that oscillating heat pipe with filling ratio of 50% started up earlier than that with 70% when heating input was 159.4 W, however, it has similar starting up performance with filling ratio of 50% as compared to 70% on the condition of heat input of 205.4 W. And heat pipe with filling ratio of 10% could not start up but directly transit to dry burning. A reasonable filling ratio range of 35%-70% was needed in order to achieve better performance, and there are different optimal filling ratios with different heating inputs- the more heating input, the higher optimal filling ratio, and vice versa. However, the dry burning appeared easily with low filling ratio, especially at very low filling ratio, such as 10%. And higher filling ratio, such as 70%, resulted in higher heat transfer( dry burning) limit. With filling ratio of 70% and inclination of 75°, oscillating heat pipe with acetone started up with heating input of just 24 W, but for ethanol, it needed to be achieved 68 W, Furthermore, the start time with acetone was similar as compared to that with ethanol. For steady operating state, the heating input with acetone was about 80 W, but it transited to dry burning state when heating input was greater than 160 W. However, for ethanol, the heating input was in vicinity of 160 W. Furthermore, thermal resistance with acetone was lower than that with ethanol at the same heating input of 120 W.

关键词： closed loop with parallel channels, plate pulsating heat pipe, filling ratio, working fluid thermalproperties, start up, heat transfer performance

Numerical analysis for peristaltic transport of Carreau-Yasuda fluid with variable thermal conductivity and convective conditions

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Journal of Central South University 2015年第11期22卷 4467-4475页

作者： F.M.Abbasi T.Hayat B.Ahmad Department of Mathematics Comsats Institute of Information Technology Department of Mathematics Quaid-I-Azam University 45320 Nonlinear Analysis and Applied Mathematics (NAAM) Research Group Faculty of Science King Abdulaziz University

Peristalsis of Carreau-Yasuda fluid is investigated. Analysis is carried out in the presence of velocity slip and convective boundary conditions. Thermal conductivity of the fluid is taken to be temperature dependent. Lubrication analysis is used in the formulation of the problem. Resulting nonlinear system of equations is solved numerically. Impact of embedded parameters on the quantities of interest is examined through graphs and tables. Comparison of the behavior of the Carreau-Yasuda, Carreau and Newtonian fluid models is presented. Results show that the heat transfer rate at the wall for the Carreau fluid model is large when compared with the Newtonian or the Carreau-Yasuda fluid model. Also the heat transfer rate at the wall decreases with increase in the velocity slip and variable thermal conductivity parameters. Further, an increase in the Biot number reduces the fluid temperature by a considerable amount.

关键词： peristaltic transport Carreau-Yasuda fluid variabl

Modeling bubble column reactor with the volume of fluid approach:Comparison of surface tension models

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Chinese Journal of Chemical Engineering 2019年第11期27卷 2659-2665页

作者： Qi Liu Zhenghong Luo Department of Chemical Engineering College of Chemistry and Chemical EngineeringState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

This work aims at comparing surface tension models in VOF(Volume of fluid) modeling and investigating the effects of gas distributor and gas velocity. Hydrodynamics of a continuous chain of bubbles inside a bubble column reactor was simulated. The grid independence study was first conducted and a grid size of 1.0 mm was adopted in order to minimize the computing time without compromising the accuracy of the results. The predictions were validated by comparing the experimental studies reported in the literature. It was found that all surface tension models can describe the bubble rise and bubble plume in a column with slight deviations.

关键词： Bubble column reactor Computational fluid dynamics Volume of fluid method Surface tension models Gas distributor

An experimental study on shock wave mitigation capability of polyurea and shear thickening fluid based suspension pads

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Defence Technology（防务技术） 2018年第1期14卷 12-18页

作者： Andi Haris Heow Pueh Lee Vincent Beng Chye Tan Department of Mechanical Engineering National University of Singapore

The present experimental study investigates shock wave mitigation capability of potentially new personal protective equipment(PPE) suspension pads made from polyurea and shear thickening fluid(STF).The shock tube test results show that when placed behind Twaron fabric systems with thickness ranging from 2 mm to 18 mm, the replacement of conventional flexible foam pad with STF and STF-infused foam pads with the same thickness of 20 mm greatly reduces the normalized peak pressure(by about 72% for each pad). However, this benefit is partially offset by a large increase in the normalized impulse(by about78% for the STF pad and 131% for the STF-infused foam pad) which may cause the shock wave mitigation performance of these two pads to become less effective. Interestingly, the use of 4 mm thick polyurea pad can greatly reduce the normalized peak pressure and impulse as well(by about 74% and 49%, respectively). These results reveal that among the potentially new suspension pads tested, the polyurea pad displays the best shock wave mitigation performance. Therefore, polyurea has potential for use as a suspension pad in personal protective equipment requiring shock wave mitigation capability such as fabric ballistic vests, bomb suits and combat helmets.

关键词： Shock wave mitigation Polyurea Shear thickening fluid Suspension pad Ballistic fabric Primary blast injuries

Bayesian seismic inversion for estimating fluid content and fracture parameters in a gas-saturated fractured porous reservoir

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Science China Earth Sciences 2019年第5期62卷 798-811页

作者： Xinpeng PAN Guangzhi ZHANG School of Sciences China University of Petroleum (East China) Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology

Understanding the effects of in situ fluid content and fracture parameters on seismic characteristics is important for the subsurface exploration and production of fractured porous rocks. The ratio of normal-to-shear fracture compliance is typically utilized as a fluid indicator to evaluate anisotropy and identify fluids filling the fractures, but it represents an underdetermined problem because this fluid indicator varies as a function of both fracture geometry and fluid content. On the bases of anisotropic Gassmann's equation and linear-slip model, we suggest an anisotropic poroelasticity model for fractured porous reservoirs. By combining a perturbed stiffness matrix and asymptotic ray theory, we then construct a direct relationship between the PP-wave reflection coefficients and characteristic parameters of fluids(P-and S-wave moduli) and fractures(fracture quasi-weaknesses), thereby decoupling the effects of fluid and fracture properties on seismic reflection *** incorporating fracture quasi-weakness parameters, we propose a novel parameterization method for elastic impedance variation with offset and azimuth(EIVOA). By incorporating wide-azimuth observable seismic reflection data with regularization constraints, we utilize Bayesian seismic inversion to estimate the fluid content and fracture parameters of fractured porous rocks. Tests on synthetic and real data demonstrate that fluid and fracture properties can be reasonably estimated directly from azimuthal seismic data and the proposed approach provides a reliable method for fluid identification and fracture characterization in a gas-saturated fractured porous reservoir.

关键词： fluid parameters Fracture parameters Fractured porous reservoir Poroelasticity theory Bayesian seismic inversion

Computational fluid Dynamics Benchmark of an Impulse Turbine with Fixed Guide Vanes

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Journal of Thermal Science 2004年第2期13卷 109-113,108页

作者： Ajit THAKKER Fergal HOURIGAN T. SETOGUCHI M. TAKAO Wave Energy Research Team Department of Mechanical and Aeronautical Engineering University of Limerick Limerick IrelandWave Energy Research Team Department of Mechanical and Aeronautical Engineering University of Limerick Limerick IrelandDepartment of Mechanical Engineering Saga University 1 Honjo-machi Saga-shi Saga 840-8502 JapanDepartment of Control Engineering Matsue National College of Technology 14-4 Nishiikuma-cho Matsue-shi Shimane 690-8518 Japan

This paper presents the comparison of a three dimensional Computational fluid Dynamics (CFD) analysis with empirical performance data of a 0.6 m impulse turbine with fixed guide vanes used for wave energy power conversion. Pro-Engineer, Gambit and Fluent 6 were used to create a 3-D model of the turbine. A hybrid meshing scheme was used with hexahedral cells in the near blade region and tetrahedral and pyramid cells in the rest of the domain. The turbine has a hub-to-tip ratio of 0.6 and results were obtained over a wide range of flow coefficients. The model yielded a maximum efficiency of approximately 54% as compared to a maximum efficiency of around 49% from experiment. A degree of insight into flow behaviour, not possible with experiment, was obtained.

关键词： wave energy impulse turbine computational fluid dynamics CFD hybrid mesh.

INERTIA EFFECTS OF THE fluid AND CYLINDER IN COAXIAL CYLINDRICAL RHEOMETER

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Acta Mechanica Sinica 1998年第3期14卷 234-238页

作者：张建保匡震邦 Dept.of Physics The Forth Military Medical UniversityXi'an 710032China Dept.of Eng.Mechanics Shanghai Jiaotong UniversityShanghai 200240China

The inertias of the fluid and the inner cylinder in coaxial cylinder rheometer (CACR) have great influence on the unsteady flow of non-Newtonian fluid. Even for the Newtonian fluid there exist the so called stress overshoot phenomenon. This phenomenon was studied and a method correcting the measured results for an unsteady flow in the rheometer was proposed. It is found that the inertia effect of the fluid can be ignored when the gap between cylinders is small. (Edited author abstract) 11 Refs.

关键词： inertia rheometer fluid hemorheology

Study of Formation and Propagation of Streamers in SF_6 and Its Gas Mixtures with Low Content of SF_6 Using a One-Dimensional fluid Model

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Plasma Science and Technology 2012年第3期14卷 187-191页

作者：李付亮汪沨王国利 W.PFEIFFER 何荣涛 Hunan Technical College of Water Resources and Hydropower School of Electrical and Information Engineering Hunan University National Engineering Laboratory for Ultra High Voltage Engineering Technology(Kunming Guangzhou) Technische Universitt Darmstadt 64283 DarmstadtGermany XuJi(Xiamen) Intelligent Switchgear Manufacturing Co. Ltd.

Using a hybrid Monte Carlo Collision/fluid model, the formation and propagation of streamers in SF6 and its gas mixtures are simulated. The simulation is based on an accurate numerical solution of Poisson＇s equation in conjunction with the continuity fluid equation for electrons, negative ions, and positive ions. The factors that influence the formation and propagation of streamers are investigated. The electron density, positive and negative ion density, and electric field in the discharge channel are also presented, which are very important in understanding the phenomena of streamers and in assessing the insulation strength of the gas mixture.

关键词： streamer fluid SF6 insulation

Meshwork Supported fluid Film Model of Cell Membranes

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Chinese Physics Letters 1998年第10期15卷 770-771页

作者：唐孝威 Institute of High Energy Physics Chinese Academy of SciencesBeijing 100039

A new model of cell membranes,a meshwork supported fluid film model,is proposed by unifying the features of the fluid mosaic and the skeleton *** properties of cell membranes including cell shape,cell signaling,membra... 详细信息

关键词： skeleton Mesh fluid