scholarly journals 3D Numerical Simulation and Performance Analysis of CO2 Vortex Tubes

2021 ◽  
Vol 11 (20) ◽  
pp. 9386
Author(s):  
Qijun Xu ◽  
Jinfeng Wang ◽  
Jing Xie
Keyword(s):  
Three Dimensional ◽  
Vortex Chamber ◽  
Swirl Flow ◽  
Tube Length ◽  
Maximum Pressure ◽  
Pressure Potential ◽  
Maximum Heat ◽  
Cooling Temperature ◽  
And Performance ◽  
Vortex Tubes

In view of the extensive application of swirl flow pipes (vortex tubes) in refrigeration systems, the parameters of swirl flow pipes were investigated to provide optimal cooling and heating conditions. Three-dimensional numerical simulations were carried out using available experimental data and models. The analysis verified that the heat pipe with a length of 175 mm performed better than the swirl flow pipe with a length of 125 mm, confirming experiments by Agrawal. Meanwhile, by comparing different pressures, it was found that in the single-nozzle swirl flow pipe, the greater the increase of pressure (0.1–1.0 MPa), the greater the burden on the vortex chamber and the more serious the wear is, which can be seen in the higher inlet pressure. In order to improve the durability of the swirl flow pipe, we suggest using a swirl flow pipe with more nozzles. Finally, according to the simulation results, with the rise of carbon dioxide pressure potential energy at the inlet, the cooling effect of the swirl flow is first increasing and then decreasing. When the swirl flow pipe is used as a refrigeration device to determine the minimum cooling temperature under the maximum pressure, the lowest temperature of the 125 mm swirl flow pipe was 252.4 K at 0.8 MPa, while the lowest temperature of the 175 mm swirl flow pipe was 246.0 K. Secondly, the distance from the inlet to the hot outlet of the swirl flow pipe had little effect on the cooling temperature and radial velocity, but increasing its distance increased the wall temperature of the swirl flow pipe because it increases the contact time between the airflow and the hot end of the tube wall. When the swirl flow pipe is used as a heat-producing device, increasing the tube length of the swirl flow pipe appropriately increases its maximum heat-producing temperature.

scholarly journals Numerical Simulation of the Effect of Different Numbers of Inlet Nozzles on Vortex Tubes

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1531
Author(s):  
Qijun Xu ◽  
Jing Xie
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Gas Flow ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Vortex Chamber ◽  
Inlet Pressure ◽  
Energy Separation ◽  
Outlet Temperature ◽  
Vortex Tubes

In order to broaden the application of vortex tubes (VOTU) in industry and to improve the efficiency of cooling and heating, numerical simulations of vortex tubes were carried out. In this study, the temperature, velocity, and pressure fields of three VOTUs with inlet nozzles of 2, 3, and 6 were investigated at different inlet pressures based on previous experimental data and by three-dimensional numerical simulation. It was found that the increase of inlet pressure leads to the increase of energy separation between the hot and cold ends of the three VOTUs. As the number of inlets increases, the pressure difference between the tube wall and the core region gradually strengthens. In contrast, the pressure in the tube center is not affected by the inlet pressure. The number of nozzles affects the inlet and outlet temperatures of the VOTU. When the number of nozzles is 3, and the inlet pressure is 0.6 MPa, the VOTU shows the maximum hot and cold outlet temperature difference of 66 K. The maximum velocity of VOTU appears at the connection of the inlet and vortex chamber, so the inlet is tangential to VOTU, which is beneficial to reduce the loss of gas energy. The wall thickness of the inlet increases gradually to avoid the high-speed gas flow on the erosion of the wall surface. This study has profound guidance for the one-dimensional design of VOTUs.

Digitalization system of ancient architecture decoration art based on neural network and image features

2020 ◽  
pp. 1-12
Author(s):  
Wu Xin ◽  
Qiu Daping
Keyword(s):  
Neural Network ◽  
Construction Industry ◽  
Three Dimensional ◽  
Performance Testing ◽  
Image Features ◽  
Three Dimensional Model ◽  
Performance Effect ◽  
Data Process ◽  
And Performance ◽  
Construction Mode

The inheritance and innovation of ancient architecture decoration art is an important way for the development of the construction industry. The data process of traditional ancient architecture decoration art is relatively backward, which leads to the obvious distortion of the digitalization of ancient architecture decoration art. In order to improve the digital effect of ancient architecture decoration art, based on neural network, this paper combines the image features to construct a neural network-based ancient architecture decoration art data system model, and graphically expresses the static construction mode and dynamic construction process of the architecture group. Based on this, three-dimensional model reconstruction and scene simulation experiments of architecture groups are realized. In order to verify the performance effect of the system proposed in this paper, it is verified through simulation and performance testing, and data visualization is performed through statistical methods. The result of the study shows that the digitalization effect of the ancient architecture decoration art proposed in this paper is good.

Sea Urchins and Circuses: The Modernist Natural Histories of Jean Painlevé and Alexander Calder

2018 ◽  
Vol 13 (2) ◽  
pp. 187-211
Author(s):  
Patricia E. Chu
Keyword(s):  
New Media ◽  
Sea Urchins ◽  
Life Sciences ◽  
Three Dimensional ◽  
Machine Age ◽  
Avant Garde ◽  
History Of ◽  
And Performance ◽  
The One ◽  
Natural Historian

The Paris avant-garde milieu from which both Cirque Calder/Calder's Circus and Painlevé’s early films emerged was a cultural intersection of art and the twentieth-century life sciences. In turning to the style of current scientific journals, the Paris surrealists can be understood as engaging the (life) sciences not simply as a provider of normative categories of materiality to be dismissed, but as a companion in apprehending the “reality” of a world beneath the surface just as real as the one visible to the naked eye. I will focus in this essay on two modernist practices in new media in the context of the history of the life sciences: Jean Painlevé’s (1902–1989) science films and Alexander Calder's (1898–1976) work in three-dimensional moving art and performance—the Circus. In analyzing Painlevé’s work, I discuss it as exemplary of a moment when life sciences and avant-garde technical methods and philosophies created each other rather than being classified as separate categories of epistemological work. In moving from Painlevé’s films to Alexander Calder's Circus, Painlevé’s cinematography remains at the forefront; I use his film of one of Calder's performances of the Circus, a collaboration the men had taken two decades to complete. Painlevé’s depiction allows us to see the elements of Calder's work that mark it as akin to Painlevé’s own interest in a modern experimental organicism as central to the so-called machine-age. Calder's work can be understood as similarly developing an avant-garde practice along the line between the bestiary of the natural historian and the bestiary of the modern life scientist.

Electrical Capacitance Volume Tomography (ECVT) for industrial and medical applications-An Overview

2015 ◽  
Vol 11 (1) ◽  
pp. 2897-2908
Author(s):  
Mohammed S.Aljohani
Keyword(s):  
Imaging Technique ◽  
Three Dimensional ◽  
Biological Processes ◽  
Electrical Capacitance ◽  
Image Reconstruction Techniques ◽  
Phase Dynamics ◽  
Non Invasive ◽  
Electrical Capacitance Volume Tomography ◽  
And Performance ◽  
Optimization And Performance

Tomography is a non-invasive, non-intrusive imaging technique allowing the visualization of phase dynamics in industrial and biological processes. This article reviews progress in Electrical Capacitance Volume Tomography (ECVT). ECVT is a direct 3D visualizing technique, unlike three-dimensional imaging, which is based on stacking 2D images to obtain an interpolated 3D image. ECVT has recently matured for real time, non-invasive 3-D monitoring of processes involving materials with strong contrast in dielectric permittivity. In this article, ECVT sensor design, optimization and performance of various sensors seen in literature are summarized. Qualitative Analysis of ECVT image reconstruction techniques has also been presented.

Advances in coupled axial turbine and nonaxisymmetric exhaust volute aerodynamics for turbomachinery

2020 ◽  
pp. 095441002096645
Author(s):  
Jie Gao ◽  
Chunde Tao ◽  
Dongchen Huo ◽  
Guojie Wang
Keyword(s):  
Performance Improvement ◽  
High Efficiency ◽  
Three Dimensional ◽  
Great Influence ◽  
Aerodynamic Characteristics ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Axial Turbine ◽  
Flow Interactions ◽  
And Performance

Marine, industrial, turboprop and turboshaft gas turbine engines use nonaxisymmetric exhaust volutes for flow diffusion and pressure recovery. These processes result in a three-dimensional complex turbulent flow in the exhaust volute. The flows in the axial turbine and nonaxisymmetric exhaust volute are closely coupled and inherently unsteady, and they have a great influence on the turbine and exhaust aerodynamic characteristics. Therefore, it is very necessary to carry out research on coupled axial turbine and nonaxisymmetric exhaust volute aerodynamics, so as to provide reference for the high-efficiency turbine-volute designs. This paper summarizes and analyzes the recent advances in the field of coupled axial turbine and nonaxisymmetric exhaust volute aerodynamics for turbomachinery. This review covers the following topics that are important for turbine and volute coupled designs: (1) flow and loss characteristics of nonaxisymmetric exhaust volutes, (2) flow interactions between axial turbine and nonaxisymmetric exhaust volute, (3) improvement of turbine and volute performance within spatial limitations and (4) research methods of coupled turbine and exhaust volute aerodynamics. The emphasis is placed on the turbine-volute interactions and performance improvement. We also present our own insights regarding the current research trends and the prospects for future developments.

scholarly journals Numerical Study toward Optimization of Spray Drying in a Novel Radial Multizone Dryer

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1233
Author(s):  
Umair Jamil Ur Rahman ◽  
Artur Krzysztof Pozarlik ◽  
Thomas Tourneur ◽  
Axel de Broqueville ◽  
Juray De Wilde ◽  
...  
Keyword(s):  
Spray Drying ◽  
Droplet Size ◽  
Separation Efficiency ◽  
Numerical Study ◽  
Three Dimensional ◽  
Droplet Size Distribution ◽  
Vortex Chamber ◽  
Temperature Pattern ◽  
Multiphase Model ◽  
Drying Technology

In this paper, an intensified spray-drying process in a novel Radial Multizone Dryer (RMD) is analyzed by means of CFD. A three-dimensional Eulerian–Lagrangian multiphase model is applied to investigate the effect of solids outlet location, relative hot/cold airflow ratio, and droplet size on heat and mass transfer characteristics, G-acceleration, residence time, and separation efficiency of the product. The results indicate that the temperature pattern in the dryer is dependent on the solids outlet location. A stable, symmetric spray behavior with maximum evaporation in the hot zone is observed when the solids outlet is placed at the periphery of the vortex chamber. The maximum product separation efficiency (85 wt %) is obtained by applying high G-acceleration (at relative hot/cold ratio of 0.75) and narrow droplet size distribution (45–70 µm). The separation of different sized particles with distinct drying times is also observed. Smaller particles (<32 µm) leave the reactor via the gas outlet, while the majority of big particles leave it via the solids outlet, thus depicting in situ particle separation. The results revealed the feasibility and benefits of a multizone drying operation and that the RMD can be an attractive solution for spray drying technology.

scholarly journals Precise point positioning with GPS and Galileo broadcast ephemerides

GPS Solutions ◽  
2021 ◽  
Vol 25 (2) ◽  
Author(s):  
Luca Carlin ◽  
André Hauschild ◽  
Oliver Montenbruck
Keyword(s):  
Precise Point Positioning ◽  
Three Dimensional ◽  
Test Results ◽  
Process Noise ◽  
Functional Models ◽  
Ambiguity Estimation ◽  
Point Positioning ◽  
And Performance ◽  
Range Error ◽  
Space Range

AbstractFor more than 20 years, precise point positioning (PPP) has been a well-established technique for carrier phase-based navigation. Traditionally, it relies on precise orbit and clock products to achieve accuracies in the order of centimeters. With the modernization of legacy GNSS constellations and the introduction of new systems such as Galileo, a continued reduction in the signal-in-space range error (SISRE) can be observed. Supported by this fact, we analyze the feasibility and performance of PPP with broadcast ephemerides and observations of Galileo and GPS. Two different functional models for compensation of SISREs are assessed: process noise in the ambiguity states and the explicit estimation of a SISRE state for each channel. Tests performed with permanent reference stations show that the position can be estimated in kinematic conditions with an average three-dimensional (3D) root mean square (RMS) error of 29 cm for Galileo and 63 cm for GPS. Dual-constellation solutions can further improve the accuracy to 25 cm. Compared to standard algorithms without SISRE compensation, the proposed PPP approaches offer a 40% performance improvement for Galileo and 70% for GPS when working with broadcast ephemerides. An additional test with observations taken on a boat ride yielded 3D RMS accuracy of 39 cm for Galileo, 41 cm for GPS, and 27 cm for dual-constellation processing compared to a real-time kinematic reference solution. Compared to the use of process noise in the phase ambiguity estimation, the explicit estimation of SISRE states yields a slightly improved robustness and accuracy at the expense of increased algorithmic complexity. Overall, the test results demonstrate that the application of broadcast ephemerides in a PPP model is feasible with modern GNSS constellations and able to reach accuracies in the order of few decimeters when using proper SISRE compensation techniques.

scholarly journals Effect of Structural Differences on the Mechanical Properties of 3D Integrated Woven Spacer Sandwich Composites

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4284
Author(s):  
Lvtao Zhu ◽  
Mahfuz Bin Rahman ◽  
Zhenxing Wang
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Three Dimensional ◽  
Sheet Thickness ◽  
Physical And Mechanical Properties ◽  
Sandwich Composites ◽  
Computed Tomography Images ◽  
And Performance ◽  
Industrial Textiles ◽  
Load Conditions

Three-dimensional integrated woven spacer sandwich composites have been widely used as industrial textiles for many applications due to their superior physical and mechanical properties. In this research, 3D integrated woven spacer sandwich composites of five different specifications were produced, and the mechanical properties and performance were investigated under different load conditions. XR-CT (X-ray computed tomography) images were employed to visualize the microstructural details and analyze the fracture morphologies of fractured specimens under different load conditions. In addition, the effects of warp and weft direction, face sheet thickness, and core pile height on the mechanical properties and performance of the composite materials were analyzed. This investigation can provide significant guidance to help determine the structure of composite materials and design new products according to the required mechanical properties.

scholarly journals Effects of 3D Printing-Line Directions for Stretchable Sensor Performances

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1791
Author(s):  
Chi Cuong Vu ◽  
Thanh Tai Nguyen ◽  
Sangun Kim ◽  
Jooyong Kim
Keyword(s):  
3D Printing ◽  
Thermoplastic Polyurethane ◽  
Three Dimensional ◽  
Optimal Solution ◽  
Human Motion ◽  
Repeated Measurements ◽  
Fused Filament Fabrication ◽  
And Performance ◽  
The Times ◽  
Stretchable Sensors

Health monitoring sensors that are attached to clothing are a new trend of the times, especially stretchable sensors for human motion measurements or biological markers. However, price, durability, and performance always are major problems to be addressed and three-dimensional (3D) printing combined with conductive flexible materials (thermoplastic polyurethane) can be an optimal solution. Herein, we evaluate the effects of 3D printing-line directions (45°, 90°, 180°) on the sensor performances. Using fused filament fabrication (FDM) technology, the sensors are created with different print styles for specific purposes. We also discuss some main issues of the stretch sensors from Carbon Nanotube/Thermoplastic Polyurethane (CNT/TPU) and FDM. Our sensor achieves outstanding stability (10,000 cycles) and reliability, which are verified through repeated measurements. Its capability is demonstrated in a real application when detecting finger motion by a sensor-integrated into gloves. This paper is expected to bring contribution to the development of flexible conductive materials—based on 3D printing.

A Computational Analysis of Flow Field in Twin-Track Subway Tunnel to Improve Air Quality

2013 ◽  
Vol 319 ◽  
pp. 599-604
Author(s):  
Makhsuda Juraeva ◽  
Kyung Jin Ryu ◽  
Sang Hyun Jeong ◽  
Dong Joo Song
Keyword(s):  
Air Quality ◽  
Computational Model ◽  
Stokes Equations ◽  
Ventilation System ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Subway Tunnel ◽  
Air Supply ◽  
And Performance

A computational model of existing Seoul subway tunnelwas analyzed in this research. The computational model was comprised of one natural ventilationshaft, two mechanical ventilationshafts, one mechanical airsupply, a twin-track tunnel, and a train. Understanding the flow pattern of the train-induced airflow in the tunnel was necessary to improve ventilation performance. The research objective wasto improve the air quality in the tunnel by investigating train-induced airflow in the twin-track subway tunnel numerically. The numerical analysis characterized the aerodynamic behavior and performance of the ventilation system by solving three-dimensional turbulent Reynolds-averaged Navier-Stokes equations. ANSYS CFX software was used for the computations. The ventilation and aerodynamic characteristics in the tunnel were investigated by analyzing the mass flowrateat the exits of the ventilation mechanicalshafts. As the train passed the mechanical ventilation shafts, the amount of discharged-air in the ventilationshafts decreased rapidly. The air at the exits of the ventilation shafts was gradually recovered with time, after the train passed the ventilation shafts. The developed mechanical air-supply for discharging dusty air and supplying clean airwas investigated.The computational results showed that the developed mechanical air-supplycould improve the air quality in the tunnel.

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