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 Temperature Measurement of Fluid Flows by Using a Focusing Schlieren Method

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 12 ◽  
Author(s):  
A. Martínez-González ◽  
D. Moreno-Hernández ◽  
J. Guerrero-Viramontes ◽  
M. León-Rodríguez ◽  
J. Zamarripa-Ramírez ◽  
...  
Keyword(s):  
Fluid Flows ◽  
Calibration Procedure ◽  
Temperature Fields ◽  
Schlieren Image ◽  
Intensity Level ◽  
Schlieren Method ◽  
Schlieren Technique ◽  
Hot Air ◽  
Air Gun ◽  
Experimental Values

A method for measuring planar temperature fields of fluid flows is proposed. The focusing schlieren technique together with a calibration procedure to fulfill such a purpose is used. 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. The experimental values of temperature measurements are in agree with those measured using a thermocouple.

scholarly journals A novel approach involving a microcatheter tip during aneurysmal coil embolization: The Γ (gamma) tip method

2019 ◽  
Vol 25 (6) ◽  
pp. 681-684 ◽  
Author(s):  
Tomotaka Ohshima ◽  
Shigeru Miyachi ◽  
Naoki Matsuo ◽  
Reo Kawaguchi ◽  
Ryuya Maejima ◽  
...  
Keyword(s):  
Coil Embolization ◽  
Parent Artery ◽  
Hot Air ◽  
Dynamic Movement ◽  
Air Gun ◽  
Novel Approach ◽  
Endovascular Coil Embolization ◽  
Aneurysmal Neck ◽  
Novel Strategy

Complete and secure occlusion of the entire aneurysmal neck remains a problem despite major advances in the treatment of intracranial aneurysms using endovascular coil embolization. Here, we present our initial clinical experience using a novel strategy for endovascular coil embolization involving a microcatheter tip, known as the “Γ (gamma) tip method,” and compare the in vitro results of this technique with those of conventional straight microcatheters. The microcatheters were bent at a right angle starting 1–2 mm from the length of the tip using a catheter-shaping mandrel and a hot air gun. The tiny right-angled tip is the “Γ tip.” In aneurysm models, we assessed the efficacy of shaping during coil deployment. The Γ-tipped microcatheters demonstrated better movement and oscillation during insertion of the coil into the aneurysm compared with the straight-tipped catheters. Moreover, the Γ-tipped microcatheter provided less coil protrusion into the parent artery and less microcatheter kickback compared with the straight tip. With the Γ-tipped microcatheter, even if the first coil loop migrated into the parent artery, its subsequent dynamic movement routed it back into the aneurysm. The Γ tip method enabled smooth movement of the microcatheter into the aneurysm, demonstrating the safety and security of coil insertion using the Γ tip compared with the conventional straight tip.

Braking System Cooling Time Simulation

2003 ◽  
Author(s):  
Luiz Tobaldini Neto ◽  
Ramon Papa ◽  
Luis C. de Castro Santos
Keyword(s):  
Stokes Equations ◽  
Thermal Environment ◽  
Computational Cost ◽  
Calibration Procedure ◽  
Accurate Solution ◽  
Temperature Fields ◽  
Convection Flow ◽  
Time Interval ◽  
Braking System ◽  
The Impact

Aircraft braking pads are subject to an extremely severe thermal environment. During a typical landing the carbon brake pads can reach temperatures up to 700–800 K or even more. Between landings during the taxi and parking phase the brakes have to cool off back to their operational limits in a time interval consistent with the average operational time. In order to evaluate the impact of design modifications on the wheel mounting and fairings, without the need of extensive laboratory and flight campaigns, a CFD (Computational Fluid Dynamics) based methodology was developed. Due to the geometry complexity the need of a geometrically representative, but simplified model comes up, in order to capture the major features of the natural convection flow and temperature fields and can be used to evaluate the influence of design changes on the braking system cooling times. A calibration procedure is carried out, aiming a better representation of the transient phenomenon, using a thermal resistances setting up feature from the solver used. An example of the application of this methodology is presented. A computational grid of over 700,000 tetrahedral elements was constructed and the Navier-Stokes equations are solved using a commercial package (FLUENT). The computational cost for a time accurate solution demands the use of parallel processing in order to complete the analysis in a typical industrial environment timeframe. Comparison with both laboratory and flight data calibrate and validate the results of the computational model. This paper describes the details of the construction of the CFD model, the setting of the initial and boundary conditions and the comparison between measured and simulated parameters.

Calibration Procedure for Attenuation Coefficient Measurements in Highly Opaque Media Using Infrared Focal Plane Array (IRFPA) Spectroscopy

2018 ◽  
Vol 72 (2) ◽  
pp. 177-187 ◽  
Author(s):  
Sara Kirchner ◽  
Sebastien Narinsamy ◽  
Alain Sommier ◽  
Marta Romano ◽  
Meguya Ryu ◽  
...  
Keyword(s):  
Coming Out ◽  
Focal Plane ◽  
Aqueous Media ◽  
Focal Plane Array ◽  
Calibration Procedure ◽  
Integration Time ◽  
Intensity Level ◽  
Infrared Focal Plane Array ◽  
Ir Spectroscopic

The purpose of this article is to present a new calibration procedure for spectroscopic measurements using an infrared focal plane array (IRFPA) spectrometer on highly opaque middle-wave infrared (MWIR) media. The procedure is based on the properties of the IRFPA camera and especially the integration time (IT), which is the main parameter that can be adjusted to control the sensitivity of the measurements. The goal of the paper is to experimentally validate this dependence with the direct reference intensity light coming out of the IR monochromator in order to predict the spectrum shape and intensity level in a range out of the camera saturation. This method allows determining spectrum used as background for transmittance calculation. It has been applied in the case of measurement of water transmittance, which is a highly opaque medium and whose measurement requires high ITs. The main result is the ability to take an IR spectroscopic imaging measurement through 300 µm of water and the determination of its transmittance with sufficient sensitivity due to the proposed calibration procedure. This procedure allows the possibility of transitory studies in heterogeneous aqueous media.

Insulation Systems of Frameless Buildings

2020 ◽  
Vol 992 ◽  
pp. 66-72
Author(s):  
Ekaterina Yu. Bobrova ◽  
K.A. Ter-Zakaryan ◽  
Alexey D. Zhukov ◽  
A.A. Medvedev ◽  
A.I. Poserenin
Keyword(s):  
Thermal Imaging ◽  
Weld Seam ◽  
Raw Material ◽  
Environmental Friendliness ◽  
Longitudinal Tensile Strength ◽  
Hot Air ◽  
Air Gun ◽  
Insulation Systems ◽  
Metallized Coating ◽  
Side Walls

The article analyzes different ways of creating an insulating coating within the scope of frameless buildings. Among such constructions, the production halls, raw material and finished-products storages, agricultural storages, livestock housing, garages, covered parking, sports and cultural facilities are to be distinguished. Criteria that the heat-insulating materials should meet in the context of effective and durable insulation coatings are low thermal conductivity, vapor and water permeability, high operational durability and environmental friendliness as well. It is confirmed that products based on polyethylene foam, such as mats and rolls, fully meet the above-mentioned criteria. Furthermore, the possibility of obtaining a seamless joint during the installation process significantly increases the effectiveness of the insulating coating by means of minimizing cold bridges and eliminating leakages when connecting separate insulating elements. Polyethylene foam is an elastic and well stretching material. When fixing polyethylene foam rolls on the metal covering of the frameless construction, they will change their shape together with the metal due to the climatic temperature drops (stretch and constrict). The performed tests have revealed that the longitudinal tensile strength of the products with a metallized coating is 80–92 kPa, without a metallized coating - 80–87 kPa, and 29–32 kPa of the weld seam. The article includes information regarding the results of thermal imaging monitoring of frameless constructions with an insulating coating based on polyethylene foam. It is shown that hot-air welding (with the help of a hot air gun) allows minimizing heat losses both at the joints of the sheets and in the areas adjoining to the base and to the side walls of the buildings.

On-line Consolidation of Commingled Polypropylene/Glass Roving During Filament Winding

2011 ◽  
Vol 24 (6) ◽  
pp. 789-804 ◽  
Author(s):  
R. Gennaro ◽  
F. Montagna ◽  
A. Maffezzoli ◽  
F. Fracasso ◽  
S. Fracasso
Keyword(s):  
Filament Winding ◽  
Void Content ◽  
Processing Conditions ◽  
Hot Air ◽  
Air Gun ◽  
On Line ◽  
Set Up ◽  
Comparison Of The Results ◽  
Composite Samples

In this study, the in situ consolidation of polypropylene matrix/glass reinforced rovings was performed combining two heating systems, an infrared oven and a hot air gun, and a roll pressing the commingled roving during hoop winding on a cylindrical mandrel. Process parameters were set up on the basis of a preliminary simulation of the heat transfer along the roving and then comparison of the results with experimental temperature profiles obtained by a noncontact thermometer. Composite samples were cut along the cylinder axis for mechanical characterization. Physical properties, such as density and void content, obtained using different processing conditions, were compared. Electron microscopy was performed in order to assess how processing conditions affect fiber–matrix impregnation.

Use of the schlieren method to investigate temperature fields in a solid

1971 ◽  
Vol 20 (3) ◽  
pp. 372-374 ◽  
Author(s):  
Yu. A. Napar'in ◽  
V. I. Shakhurdin
Keyword(s):  
Temperature Fields ◽  
Schlieren Method

scholarly journals Method of Polychromatic Hilbert Diagnostics of Phase and Temperature Perturbations of Axisymmetric Flames

2021 ◽  
Author(s):  
Vitaly Arbuzov ◽  
Eduard Arbuzov ◽  
Yuri Dubnishchev ◽  
Olga Zolotukhina ◽  
Vladimir Lukashov
Keyword(s):  
Temperature Field ◽  
Optical Density ◽  
Axial Symmetry ◽  
Hydrogen Diffusion ◽  
Temperature Fields ◽  
Radial Temperature ◽  
Hot Air ◽  
Density Perturbations ◽  
Subsequent Calculation ◽  
Candle Flame

The work is aimed at solving the scientific and practical problem of non-disturbing diagnostics of the phase and temperature fields of reacting jets and flames. On the example of an axisymmetric hydrogen-diffusion flame and a hot air flow from a candle flame, a method was developed that is adequate to the problem being solved, based on Hilbert polychromatic visualization of phase optical density fields, measuring the temperature profile in selected areas of the medium under study, pixel-by-pixel processing of RAW images recorded by a photographic matrix in RGB channels. The visualized Hilbert structures carry information about the phase optical density perturbations induced by the temperature field. The phase structure of the probing light field in the axial symmetry approximation of the flame under investigation is analyzed using the Abel transform. Iterative selection of radial temperature profiles, adapted Bezier curves, is performed with the subsequent calculation of the spatial structure of the refractive index and phase function. The reconstruction of the temperature field by the example of the study of a hydrogen-air flame is carried out taking into account the diversity of the partial optical properties of the gas mixture in a model consistent with the Gladstone-Dale dispersion formula. The influence of disturbances in the air surrounding the flame on its axial symmetry is discussed. The criterion for the reliability of the research results is a comparison of the hilbertograms obtained in the experiment and the hilbertograms reconstructed from phase structures induced by temperature fields.

scholarly journals The effect of technological parameters of PMMA thermoplastic welding in the hot air stream on the quality of joints

2019 ◽  
Vol 91 (8) ◽  
pp. 13-24 ◽  
Author(s):  
Damian Przewodowski ◽  
Dariusz Golański
Keyword(s):  
Tensile Test ◽  
Welded Joints ◽  
Joint Strength ◽  
Side Wall ◽  
Welding Parameters ◽  
Technological Parameters ◽  
Visual Evaluation ◽  
Hot Air ◽  
Air Gun ◽  
The Impact

The work covers the welding of thermoplastic polymethyl methacrylate (PMMA) and concerns the assessment of the impact of the main welding parameters on joint strength. The strength test of welded joints made of thermoplastic material was carried out. The aim of the study was to determine the influence of the main technological parameters of welding, such as: temperature and welding speed, gas stream output, filler rod pressure, diameter and type of hot air gun nozzle on the strength of the obtained joint. The method of sample preparation and testing was performed in accordance with the guidelines of PN-EN 12814-2: 2002 "Tests of welded joints in semi-finished products made of thermoplastics ‒ Part 2: Tensile test". Visual evaluation of welded samples and analysis of results obtained from the tensile test made it possible to draw conclusions about the influence of selected welding parameters on joint strength. The decisive influence on the strength of joints was caused by welding defects, in the form of lack of side wall fusion and porosity.

Application of the Rainbow Schlieren Method in Free Underexpanded Jets

2013 ◽  
Vol 313-314 ◽  
pp. 750-753
Author(s):  
Wen Tang Wu ◽  
Yan Ji Hong ◽  
Ji Fei Ye ◽  
Guan Lei Jiang
Keyword(s):  
Experimental Investigation ◽  
Pressure Ratio ◽  
Schlieren Method ◽  
Schlieren Technique ◽  
Underexpanded Jets ◽  
Schlieren System ◽  
Operation Method ◽  
Nozzle Pressure ◽  
Jet Structure ◽  
Rainbow Schlieren

An experimental investigation into free underexpanded jets is described. In this paper the experiment took the axis-symmetry unexpended jets as the object, used the typical "Z" schlieren system and replaced the edge with rainbow filter.The rainbow schlieren method is used to obtain measurements in underexpanded jets with nozzle pressure ratios ranging from 2.97 to 19.80. Obtaining the result of that the influence of pressure ratio on jet structure. This paper provides an operation method in the concrete and some useful reference for the rainbow schlieren technique.

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