An improved inversion algorithm to reconstruct 2D temperature fields of long sparks with high-speed schlieren technique

Measurement ◽  
2021 ◽  
pp. 109620
Author(s):  
Xiaopeng Liu ◽  
Xiankang Wang ◽  
Xiangen Zhao ◽  
Pei Xiao ◽  
Yang Liu ◽  
...  
Keyword(s):  
High Speed ◽  
Temperature Fields ◽  
Inversion Algorithm ◽  
Schlieren Technique

Thermal Wake of a Single Rising Air Bubble in a Large Body of Stagnant Liquid

2007 ◽  
Author(s):  
Majid Molki ◽  
Bahman Abbasi
Keyword(s):  
High Speed ◽  
Thermal Field ◽  
Large Body ◽  
Heat Transfer Process ◽  
Computational Effort ◽  
Temperature Fields ◽  
High Speed Photography ◽  
Three Dimensional Model ◽  
Surrounding Water ◽  
Air Bubble

A computational effort was undertaken to study the thermal field behind a slowly rising solitary air bubble. Starting from rest, the bubble moves upward in water due to buoyancy force in the gravitational field and induces both internal and external motion. The bubble, being colder than the surrounding water, is heated by water. The upward motion deforms the shape of the bubble and generates a convective heat transfer process. Variation of temperature at the gas-liquid interface causes a local variation of surface tension. Although the problems of this type have been generally treated by the axisymmetric assumption, the present work employs a three-dimensional model that captures the azimuthal variation of flow parameters. High-speed photography was employed to visualize the bubble evolution from the onset until the bubble reached a certain velocity. The computations were performed using the finite-volume and Volume of Fluid (VOF) techniques. The shape and evolution of the bubble as predicted by the computations are compared with those captured on the high-speed photographs. The computations revealed details of the pressure and temperature fields inside and outside the bubble. They also indicated the thermal field in the wake region behind the bubble.

Numerical Simulation and Analysis of Effect of Injection Volume on Biomass Particle Cyclone Venturi Dryer

2021 ◽  
Author(s):  
Guohai Jia ◽  
Guoshuai Tian ◽  
Zicheng Gao ◽  
Dan Huang ◽  
Wei Li ◽  
...  
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Gas Flow ◽  
Continuous Phase ◽  
Temperature Fields ◽  
Maximum Pressure ◽  
Two Phase ◽  
Velocity Change ◽  
Injection Volume ◽  
Wood Debris

Abstract Cyclone venturi dryer is suitable for drying materials with large particle size and wide distribution. The working process of cyclone venturi dryer is a very complicated three-dimensional and turbulent motion, so it is difficult to be studied theoretically and experimentally. In order to study the internal flow characteristics of the biomass particle cyclone venturi dryer, the computational fluid dynamics (CFD) software was used to simulate the gas-solid two-phase flow field inside the cyclone venturi dryer. The continuous phase adopts the Realizable k-ε turbulence model and the particle phase is discrete. The effects of different injection volume on the pressure, velocity, and temperature fields inside a cyclone venturi dryer were analyzed. The results showed that the maximum pressure drop and velocity change inside the dryer were at the venturi pipe. The wet material of the cyclone venturi dryer was inhaled into the venturi contraction tube by the negative pressure formed after the highspeed airflow was ejected, thus the mixture was completed in the venturi throat. The wood debris material was mixed with the high-speed hot gas flow in the venturi throat and then sprayed into the diffusion pipe. In the diffusion pipe of venturi, the heat and mass transfer process of wet wood debris and heat flow in venturi diffusion tube was completed. It is in good agreement with the simulation results. This study can provide a reference for the optimization design of the related cyclone venturi dryer structure.

Normal Voice Production: Computation of Driving Parameters from Endoscopic Digital High Speed Images

2003 ◽  
Vol 42 (03) ◽  
pp. 271-276 ◽  
Author(s):  
T. Braunschweig ◽  
J. Lohscheller ◽  
U. Eysholdt ◽  
U. Hoppe ◽  
M. Döllinger
Keyword(s):  
Vocal Fold ◽  
High Speed ◽  
Biomechanical Model ◽  
Vocal Folds ◽  
Inversion Algorithm ◽  
Knowledge Based ◽  
Normal Voice ◽  
Inversion Procedure ◽  
High Speed Glottography

Summary Objectives: A central point for quantitative evaluation of pathological and healthy voices is the analysis of vocal fold oscillations. By means of digital High Speed Glottography (HGG), vocal fold oscillations can be recorded in real time. Recently, a numerical inversion procedure was developed that allows the extraction of physiological parameters from digital high speed videos and a classification of voice disorders. The aim of this work was to validate the inversion procedure and to investigate the applicability to normal voices. Methods: High speed recordings were performed during phonation within a group of five female and five male persons with normal voices. By using knowledge based image processing algorithms, motion curves of the vocal folds were extracted at three different positions (dorsal, medial, ventral). These curves were used to obtain physiological voice parameters, and in particular the degree of symmetry of the vocal folds based upon a biomechanical model of the vocal folds. Results: The highest degree of symmetry was observed for the medial motion curves. While the dor-sally and ventrally extracted motion curves exhibited similar results concerning the degree of symmetry the performance of the algorithm was less stable. Conclusions: The inversion algorithm provides reasonable results for all subjects when applied to the medial motion curves. However, for dorsal and ventral motion curves, correct performance is reduced to 85 %.

scholarly journals Temperature Measurement of Fluids Flow by Using a Focusing Schlieren Method

2018 ◽  
Author(s):  
Adrián Martínez-González ◽  
David Moreno-Hernández ◽  
J. Ascención Guerrero-Viramontes ◽  
Miguel León-Rodríguez ◽  
J. Carlos I. Zamarripa-Ramírez ◽  
...  
Keyword(s):  
Calibration Procedure ◽  
Temperature Fields ◽  
Schlieren Image ◽  
Intensity Level ◽  
Depth Of Focus ◽  
Schlieren Method ◽  
Schlieren Technique ◽  
Hot Air ◽  
Air Gun ◽  
Grid Position

In this work, we propose a method to measure planar temperature fields of fluids flow. We used a focusing schlieren technique together with a calibration procedure to fulfill such purpose. The focusing schlieren technique uses an off-axis circular illumination to reduce the depth of focus of the optical system. The calibration procedure is based on the relation of the intensity level of each pixel of a focused schlieren image to the corresponding cutoff grid position measured at the exit focal plane of the schlieren lens.  The method is applied to measure planar temperature fields of the hot air issuing from a 10 mm diameter nozzle of a commercial Hot Air Gun Soldering Station Welding. Our tests are carried out at different temperature values and different planes along the radial position of the nozzle of the Hot Air Gun Soldering Station Welding. The temperature values obtained experimentally are in agreed with those obtained with a thermocouple.

scholarly journals Data-driven Prediction of Temperature Evolution in Metallic Additive Manufacturing Process

2021 ◽  
Author(s):  
Quy Duc Thinh Pham ◽  
Truong Vinh Hoang ◽  
Quoc Tuan Pham ◽  
Than Phuc Huynh ◽  
Van Xuan Tran ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
High Speed ◽  
High Speed Steel ◽  
Numerical Data ◽  
Temperature Evolution ◽  
Data Driven ◽  
Temperature Fields ◽  
Sampling Point ◽  
Element Analysis ◽  
Metallic Additive

In this study, a data-driven deep learning model for fast and accurate prediction of temperature evolution and melting pool size of metallic additive manufacturing processes are developed. The study focuses on bulk experiments of the M4 high-speed steel material powder manufactured by Direct Energy Deposition. Under non-optimized process parameters, many deposited layers (above 30) generate large changes of microstructure through the sample depth caused by the high sensitivity of the cladding material on the thermal history. A 2D finite element analysis (FEA) of the bulk sample, validated in a previous study by experimental measurements, is able to achieve numerical data defining the temperature field evolution under different process settings. A Feed-forward neural networks (FFNN) approach is trained to reproduce the temperature fields generated from FEA. Hence, the trained FFNN is used to predict the history of the temperature fields for new process parameter sets not included in the initial dataset. Besides the input energy, nodal coordinates, and time, five additional features relating layer number, laser location, and distance from the laser to sampling point are considered to enhance prediction accuracy. The results indicate that the temperature evolution is predicted well by the FFNN with an accuracy of 99% within 12 seconds.

Numerical analysis of high-speed wheel/rail adhesion under interfacial liquid contamination using an elastic-plastic asperity contact model

2016 ◽  
Vol 231 (1) ◽  
pp. 63-74
Author(s):  
Bing Wu ◽  
Tao Wu ◽  
Zefeng Wen ◽  
Xuesong Jin
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Present Model ◽  
Temperature Fields ◽  
Elastic Model ◽  
Asperity Contact ◽  
Roughness Parameters ◽  
Slip Ratio ◽  
Elastic Plastic ◽  
Train Speed

The objective of this paper is to investigate the high-speed wheel/rail adhesion under interfacial liquids contamination using a numerical model. This model considers the rheological property of interfacial liquids, elastic-plastic deformation of microasperities contact and the temperature across the film thickness. The pressure and the temperature fields can be obtained. The effects of train speed, surface roughness parameters, characteristic shear stress, and the slip ratio are investigated. Furthermore, the present model is compared with the elastic model and the elastic-plastic model without considering the thermal effect. The numerical results show that the train speed and temperature affects the wheel/rail adhesion significantly.

Measurements of Fire Whirls From a Single Flame in a Vertical Square Channel With Symmetrical Corner Gaps

1999 ◽  
Author(s):  
Kohyu Satoh ◽  
K. T. Yang
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Infrared Camera ◽  
Temperature Fields ◽  
Small Scale ◽  
Simulation Studies ◽  
Square Channel ◽  
Physical Measurements ◽  
Urban Fires ◽  
Important Basis

Abstract One of the most destructive forces in large urban fires is the occurrence of fire whirls. Despite the relatively recent experimental and numerical simulation studies on the global behaviors of small-scale whirling fires, much of the whirling fire phenomena still remain unknown. The purpose of this experimental study is to examine closely the detailed structures of the velocity and temperature fields in a stable whirling flame generated in a vertical square channel with symmetrical corner gaps by both physical measurements using conventional means and by quantitative observations using both a high-speed motion camera and a thermographic infrared camera. The results showed a rather complex non-uniform velocity and temperature field in the lower half of the whirling flame and could provide an important basis to validate the fire field models for the study of real large-scale fire whirls.

The Embedded Display for Temperature Fields Reconstruction Based on Win CE

2014 ◽  
Vol 513-517 ◽  
pp. 1150-1153
Author(s):  
Xiong Wan ◽  
Jia Kun Zhao ◽  
Hua Ming Zhang
Keyword(s):  
Temperature Field ◽  
High Speed ◽  
Temperature Fields ◽  
Operation System ◽  
Two Dimension ◽  
Design Idea ◽  
Intelligent Instrument

This design has proposed a method which uses the Hypogynous Computer and ARM together to get a high speed temperature field display.It displays multi re-biulded severed two dimension section by takig image superier performance of WinCE 6.0 operation system as the subject.It has introduced a design idea with modular processes, and it provides a reference for the miniaturization intelligent instrument which it's measure subject is field.

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