Computer Prediction of Local Destratification Near Low-Level Release Structures of Reservoirs

1983 ◽  
Vol 105 (1) ◽  
pp. 65-70 ◽  
Author(s):  
A. A. Busnaina ◽  
D. G. Lilley
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Axial Flow ◽  
Solution Procedure ◽  
Design Parameters ◽  
Fundamental Study ◽  
Computer Prediction ◽  
Practical Applications ◽  
Low Level ◽  
Dimensional Simulation

The Garton Pump consists of a low-energy axial flow propeller placed just below the surface so as to provide a downward directed jet of fluid and thereby locally mix reservoirs near the release structure of the dam. In this way high-quality epilimnion water is transported downwards, so obtaining local destratification and improved release water quality in the vicinity of low-level release structures. The flowfield is fully three-dimensional and a simplified numerical simulation and solution procedure has been formulated in Cartesian coordinates to include species diffusion and buoyancy forces. Comparison of predictions with experimenal data confirms that the main dynamic effects are modeled adequately and better than a previous two-dimensional simulation. This fundamental study with practical applications represents a low cost basic tool to show the influence of design parameters on the practical flowfield.

scholarly journals One-Dimensional and Three-Dimensional Numerical Investigations of Thermal Performance of Phase Change Materials in a Lithium-Ion Battery

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8386
Author(s):  
Van-Tinh Huynh ◽  
Kyoungsik Chang ◽  
Sang-Wook Lee
Keyword(s):  
Thermal Behavior ◽  
Thermal Performance ◽  
Phase Change Materials ◽  
Cfd Simulation ◽  
Cooling System ◽  
Low Cost ◽  
Three Dimensional ◽  
Lithium Ion ◽  
Design Parameters ◽  
Practical Applications

The thermal performance of a large-format (52.3 Ah) Li-ion pouch battery with an n-octadecane PCM was investigated. A simplified 1D model was employed to estimate the transient thermal behavior. Two design parameters, the thickness and the thermal conductivity of the PCM, were considered. A 0.5 mm thick n-octadecane PCM integrated with aluminum foam reduced the battery temperature to 34.3 °C and 50.7 °C at the end stage of discharging under 3C and 5C discharge rates, respectively. The 1D results compared to the 3D results were able to predict the temperature dissipation by the PCM method at the end of discharging. The 1D approach clearly produced reliable results in predicting the thermal behavior of the PCM cooling and was superior in practical applications with its low cost and time consumption. A 3D CFD simulation was able to describe the detailed temperature uniformity in the cell, which is an important factor in the design and evaluation of a battery cooling system.

scholarly journals Microdroplet-guided intercalation and deterministic delamination towards intelligent rolling origami

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Borui Xu ◽  
Xinyuan Zhang ◽  
Ziao Tian ◽  
Di Han ◽  
Xingce Fan ◽  
...  
Keyword(s):  
Low Cost ◽  
Rolling Direction ◽  
Three Dimensional ◽  
Van Der Waals Interaction ◽  
Creative Design ◽  
General Strategy ◽  
Practical Applications ◽  
On Demand ◽  
Vapor Sensing ◽  
Fundamental Research

Abstract Three-dimensional microstructures fabricated by origami, including folding, rolling and buckling, gain great interests in mechanics, optics and electronics. We propose a general strategy on on-demand and spontaneous rolling origami for artificial microstructures aiming at massive and intelligent production. Deposited nanomembranes are rolled-up in great amount triggered by the intercalation of tiny droplet, taking advantage of a creative design of van der Waals interaction with substrate. The rolling of nanomembranes delaminated by liquid permits a wide choice in materials as well as precise manipulation in rolling direction by controlling the motion of microdroplet, resulting in intelligent construction of rolling microstructures with designable geometries. Moreover, this liquid-triggered delamination phenomenon and constructed microstructures are demonstrated in the applications among vapor sensing, microresonators, micromotors, and microactuators. This investigation offers a simple, massive, low-cost, versatile and designable construction of rolling microstructures for fundamental research and practical applications.

scholarly journals Compressive Sensing Based Three-Dimensional Imaging Method with Electro-Optic Modulation for Nonscanning Laser Radar

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 748
Author(s):  
Yulong An ◽  
Yanmei Zhang ◽  
Haichao Guo ◽  
Jing Wang
Keyword(s):  
Compressive Sensing ◽  
3D Imaging ◽  
Low Cost ◽  
Functional Model ◽  
Three Dimensional ◽  
Visible Spectrum ◽  
Depth Map ◽  
Imaging Method ◽  
Practical Applications ◽  
Electro Optic

Low-cost Laser Detection and Ranging (LiDAR) is crucial to three-dimensional (3D) imaging in applications such as remote sensing, target detection, and machine vision. In conventional nonscanning time-of-flight (TOF) LiDAR, the intensity map is obtained by a detector array and the depth map is measured in the time domain which requires costly sensors and short laser pulses. To overcome such limitations, this paper presents a nonscanning 3D laser imaging method that combines compressive sensing (CS) techniques and electro-optic modulation. In this novel scheme, electro-optic modulation is applied to map the range information into the intensity of echo pulses symmetrically and the measurements of pattern projection with symmetrical structure are received by the low bandwidth detector. The 3D imaging can be extracted from two gain modulated images that are recovered by solving underdetermined inverse problems. An integrated regularization model is proposed for the recovery problems and the minimization functional model is solved by a proposed algorithm applying the alternating direction method of multiplier (ADMM) technique. The simulation results on various subrates for 3D imaging indicate that our proposed method is feasible and achieves performance improvement over conventional methods in systems with hardware limitations. This novel method will be highly valuable for practical applications with advantages of low cost and flexible structure at wavelengths beyond visible spectrum.

Computational Study of Edge Cooling for Open-Cathode Polymer Electrolyte Fuel Cell Stacks

2012 ◽  
Vol 9 (6) ◽  
Author(s):  
Agus P. Sasmito ◽  
Tariq Shamim ◽  
Erik Birgersson ◽  
Arun S. Mujumdar
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Thermal Management ◽  
Computational Study ◽  
Three Dimensional ◽  
Polymer Electrolyte Fuel Cell ◽  
Design Parameters ◽  
Two Phase ◽  
Practical Applications ◽  
The Impact

In open-cathode polymer electrolyte fuel cell (PEFC) stacks, a significant temperature rise can exist due to insufficient cooling, especially at higher current densities. To improve stack thermal management while reducing the cost of cooling, we propose a forced air-convection open-cathode fuel cell stack with edge cooling (fins). The impact of the edge cooling is studied via a mathematical model of the three-dimensional two-phase flow and the associated conservation equations of mass, momentum, species, energy, and charge. The model includes the stack, ambient, fan, and fins used for cooling. The model results predict better thermal management and stack performance for the proposed design as compared to the conventional open-cathode stack design, which shows potential for practical applications. Several key design parameters—fin material and fin geometry—are also investigated with regard to the stack performance and thermal management.

scholarly journals Strength and dynamic characteristics analyses of wound composite axial impeller

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Jifeng Wang ◽  
Jorge Olortegui-Yume ◽  
Norbert Müller
Keyword(s):  
Dynamic Characteristics ◽  
High Performance ◽  
Low Cost ◽  
Three Dimensional ◽  
Design Parameters ◽  
Modal Shape ◽  
Kevlar Fiber ◽  
Start Up ◽  
High Performance Composite ◽  
Wound Composite

AbstractA low cost, light weight, high performance composite material turbomachinery impeller with a uniquely designed blade patterns is analyzed. Such impellers can economically enable refrigeration plants to use water as a refrigerant (R718). A strength and dynamic characteristics analyses procedure is developed to assess the maximum stresses and natural frequencies of these wound composite axial impellers under operating loading conditions. Numerical simulation using FEM for two-dimensional and three-dimensional impellers was investigated. A commercially available software ANSYS is used for the finite element calculations. Analysis is done for different blade geometries and then suggestions are made for optimum design parameters. In order to avoid operating at resonance, which can make impellers suffer a significant reduction in the design life, the designer must calculate the natural frequency and modal shape of the impeller to analyze the dynamic characteristics. The results show that using composite Kevlar fiber/epoxy matrix enables the impeller to run at high tip speed and withstand the stresses, no critical speed will be matched during start-up and shut-down, and that mass imbalances of the impeller shall not pose a critical problem.

A Mathematical Analysis of Directional Solidification of Aqueous Solutions

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Gideon Ukpai ◽  
Boris Rubinsky
Keyword(s):  
Mathematical Model ◽  
Aqueous Solutions ◽  
Mathematical Models ◽  
Directional Solidification ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Design Parameters ◽  
Fundamental Study ◽  
Biological Matter ◽  
Intent To Use

Abstract Horizontal directional solidification techniques have been broadly utilized for the freezing of biological matter under conditions in which the freezing rate during solidification must be controlled and known. Directional solidification is used for diverse applications such as fundamental research on freezing of biological materials, cryopreservation of biological matter, and tissue engineering. This study is motivated by our intent to use directional solidification as a simplified model for the study of three-dimensional (3D) cryoprinting. In evaluating directional solidification in the context of 3D cryoprinting, we realized that current mathematical models of directional solidification are not adequately representative for this purpose, because they are simplified and one-dimensional (1D). Here, we introduce an experimentally verified and more representative two-dimensional (2D) mathematical model of directional solidification that can aid in the fundamental study of freezing of biological matter, in particular during 3D cryoprinting. The mathematical model was used to develop correlations between the freezing rates that a layer of an aqueous solution experiences during directional solidification and the various design parameters such as thickness of the sample and temperature gradients in the substrate. Results show that the freezing rates can be higher than those suggested by the previously used simplified 1D mathematical models. The results can be used for developing simplified models of 3D cryoprinting. In addition, the results suggest that many experimental studies on directional solidification of aqueous solutions and biological matter may require readjustment of analysis, in view of these findings.

Research on the Geometry Parameters of Diffuser Vane Influence on the Performance of Bulb Tubular Pumping System

2017 ◽  
Author(s):  
Yan Jin ◽  
Junxin Wu ◽  
Hongcheng Chen ◽  
Chao Liu
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Design Parameters ◽  
Hydraulic Loss ◽  
Three Dimensional Flow ◽  
Pump System ◽  
Pumping System ◽  
Axial Flow Pump ◽  
Cfd Method ◽  
Flow Pump

Diffuser vane of tubular pump is different with that of the axial flow pump, since the diffusion angle after the impeller is larger than as usual, which is an important part of bulb tubular pump system. By calculating the hydraulic loss of each part of bulb tubular pump system, it is found that the hydraulic loss of diffuser vane is in large proportion of the whole hydraulic loss. For this situation, focuses on the design parameters of diffuser vane such as diffuser vane length, unilateral edge diffusion angle, equivalent diffusion angle are necessary. In this paper, CFD method is used to simulate the turbulent flow in a bulb tubular pumping system with two different diffuser vanes. The three dimensional flow fields in the whole passage of pumping system with different diffuser vanes are obtained. The results show that all the main geometry parameters of the diffuser vane design affect the performances of tubular pumping system, it should be chosen the parameters reasonably based on the actual situation.

Influence of Impeller Design on Hemolysis of an Axial Blood Pump

2011 ◽  
Vol 140 ◽  
pp. 162-166
Author(s):  
Lei Liu ◽  
Fang Qun Wang ◽  
Qin Lin Wu ◽  
Wen Jue Wu ◽  
Kun Xi Qian ◽  
...  
Keyword(s):  
Traditional Method ◽  
Blood Compatibility ◽  
Three Dimensional ◽  
Axial Flow ◽  
Blood Pump ◽  
Design Parameters ◽  
Rotating Speed ◽  
Blood Damage ◽  
Axial Pump ◽  
Blood Pumps

Compared to centrifugal blood pumps, the high rotating speed of axial blood pumps lead to blood damage more easily. In order to improve blood compatibility of the axial blood pump developed by the authors, traditional method and three-dimensional streamlined method are used for axial impeller design, and rapid prototyping with ABS organic materials are adopted. Finally, hydraulic experiments and hemolysis tests have been conducted. The results reveal that the impeller design and the design parameters (diameter and length) affect the hydraulic performance and hemolysis of the axial pump obviously. The hemolysis index in axial flow impeller pump using traditional method is 0.12, while the minimum value of hemolysis index in the streamlined axial blood pump is 0.06, below the permitted hemolysis value of 0.1.

scholarly journals Simulated and Experimental Investigation of the Mechanical Properties and Solubility of 3D-Printed Capsules for Self-Healing Cement Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4578
Author(s):  
Se-Jin Choi ◽  
Ji-Hwan Kim ◽  
Hyojin Jeong ◽  
Ja-Sung Lee ◽  
Tae-Uk Lim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Cost ◽  
Three Dimensional ◽  
Design Parameters ◽  
Poly Lactic Acid ◽  
Material Strength ◽  
Cement Composites ◽  
Self Healing ◽  
Term Performance ◽  
Printing Direction

In the concrete industry, various R&D efforts have been devoted to self-healing technology, which can maintain the long-term performance of concrete structures, which is important in terms of sustainable development. Cracks in cement composites occur and propagate because of various internal and external factors, reducing the composite’s stability. Interest in “self-healing” materials that can repair cracks has led researchers to embed self-healing capsules in cement composites. Overcoming the limitations of polymer capsules produced by chemical manufacturing methods, three-dimensional (3D) printing can produce capsules quickly and accurately and offers advantages such as high material strength, low cost, and the ability to fabricate capsules with complex geometries. We performed structural analysis simulations, experimentally evaluated the mechanical properties and solubility of poly(lactic acid) (PLA) capsules, and examined the effect of the capsule wall thickness and printing direction on cement composites embedded with these capsules. Thicker capsules withstood larger bursting loads, and the capsule rupture characteristics varied with the printing angle. Thus, the capsule design parameters must be optimized for different environments. Although the embedded capsules slightly reduced the compressive strength of the cement composites, the benefit of the encapsulated self-healing agent is expected to overcome this disadvantage.

Simulation Study on Ventilation & Cooling for an Indoor Substation

2014 ◽  
Vol 672-674 ◽  
pp. 1700-1707 ◽  
Author(s):  
Rui Xu ◽  
Zhong Min Mei ◽  
Ting Fang Yu
Keyword(s):  
Natural Ventilation ◽  
Three Dimensional ◽  
Organization Design ◽  
Temperature Fields ◽  
Design Parameters ◽  
Air Distribution ◽  
Safety And Reliability ◽  
Computational Fluid Dynamics Cfd ◽  
Dimensional Simulation ◽  
Cfd Method

— Based on natural ventilation design scheme for an indoor substation, different air distribution schemes were obtained by changing height and size of air inlets and outlets. For indoor substation, three-dimensional simulation of air distribution was conducted by using Computational Fluid Dynamics (CFD) method. Ventilation & cooling effect of different indoor ventilation schemes were simulated with software (Fluent). By analyzing velocity fields and temperature fields, influences of different design parameters on safety and reliability of main transformer room of indoor substation were compared and analyzed in details. Additionally, characteristics and change rules of air distribution with different parameter variations were concluded. Considerations of ventilation organization design for main transformer room of indoor substation and recommendation for better air distribution schemes were provided. The research results also offered some guidance for design and renovation of ventilation & cooling projects of indoor substation.

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