scholarly journals Quartz Enhanced Photoacoustic Detection Based on an Elliptical Laser Beam

2020 ◽  
Vol 10 (4) ◽  
pp. 1197
Author(s):  
Zhijin Shang ◽  
Shangzhi Li ◽  
Hongpeng Wu ◽  
Lei Dong
Keyword(s):  
Laser Beam ◽  
Atmospheric Pressure ◽  
Acoustic Pressure ◽  
Fem Simulation ◽  
Quartz Tuning Fork ◽  
Simulation Software ◽  
Trace Gas ◽  
Photoacoustic Detection ◽  
Qepas Signal ◽  
Full Utilization

A quartz enhanced photoacoustic spectroscopy (QEPAS) sensor system based on an elliptical laser beam for trace gas detection was demonstrated. A Powell lens was exploited to shape the circular laser beam into an elliptical laser beam for the full utilization of the quartz tuning fork (QTF) prong spacing. Based on the finite element modeling (FEM) simulation software COMSOL, the distribution of acoustic pressure on QTF prongs with different beam shapes was simulated theoretically. The experimental results showed that the QEPAS signal based on the elliptical laser beam had a 1.4-fold improvement compared with the circular laser beam, resulting in a minimum detection limit of 418.6 ppmv and the normalized noise equivalent absorption (NNEA) of 1.51 × 10−6 cm−1 W/√Hz at atmospheric pressure.

scholarly journals Forming parameters optimizations with drawing force and die stress in wire rod drawing using rotating die under Coulomb friction

2018 ◽  
Vol 185 ◽  
pp. 00025
Author(s):  
Ing-Kiat Tiong ◽  
Un-Chin Chai ◽  
Gow-Yi Tzou
Keyword(s):  
Taguchi Method ◽  
Coulomb Friction ◽  
Effective Strain ◽  
Fem Simulation ◽  
Frictional Coefficient ◽  
Simulation Software ◽  
Drawing Force ◽  
Wire Rod ◽  
Forming Parameters ◽  
Die Stress

An optimization research is performed on the related forming parameters of wire rod drawing through a rotating die under Coulomb friction. The optimization research is conducted through finite element method (FEM) simulation combined with Taguchi method. There are two drawing characteristic optimizations have been carried out. They are the optimizations with drawing force and die stress. The forming parameters considered in this study are half die angle, frictional coefficient, die fillet, and rotating angular velocity of the rotating die. The same procedure is carried out in both optimizations. The geometrical models of the wire rod, top die and rotating die are constructed firstly in SolidWorks and imported into the FEM simulation software named DEFORM 3D. With the aid of Taguchi method, the simulation experiments are carried out. The results such as drawing force, die stress, and the corresponding signal-to-noise (S/N) ratio are obtained and compared. The influence rank of the forming parameters and the optimal combination of parameters are obtained through the response table for both optimizations. The results such as effective stress, effective strain, velocity field, drawing force, and die stress are studied. The results show that the minimizations of drawing force and die stress are successfully achieved.

Ultra-high sensitive trace gas detection based on light-induced thermoelastic spectroscopy and a custom quartz tuning fork

2020 ◽  
Vol 116 (1) ◽  
pp. 011103 ◽  
Author(s):  
Yufei Ma ◽  
Ying He ◽  
Pietro Patimisco ◽  
Angelo Sampaolo ◽  
Shunda Qiao ◽  
...  
Keyword(s):  
Tuning Fork ◽  
Quartz Tuning Fork ◽  
Gas Detection ◽  
Trace Gas ◽  
Trace Gas Detection

scholarly journals Dynamics of UV short pulse laser-induced plasmas from a ceramic material “titanium carbide”: a hydrodynamical out of equilibrium investigation

2019 ◽  
Vol 37 (01) ◽  
pp. 86-100
Author(s):  
A. Ait Oumeziane ◽  
J-D. Parisse
Keyword(s):  
Laser Beam ◽  
Ceramic Material ◽  
Material Properties ◽  
Atmospheric Pressure ◽  
Short Pulse ◽  
Plume Expansion ◽  
Pure Material ◽  
Short Pulse Laser ◽  
Helium Gas ◽  
Ionization Rates

AbstractThe present work is motivated by the numerous applications of short lasers–ceramics interaction. It aims at applying a newly developed model to investigate the dynamic of laser-induced plasmas from a ceramic material into a helium gas under atmospheric pressure. To have a better understanding of the link between the material properties, the plume characteristics and its interaction with the laser beam, a thorough examination of the entire ablation processes is conducted. Comparison with the behavior of laser-induced plumes under the same conditions from a pure material is shown to have a key role in shedding the light on what monitors the plume expansion in the background environment. Plume temperatures, velocities, ionization rates as well as elemental composition have been presented and compared under carefully chosen relevant conditions. This study is of interest for laser matter applications depending on the induced plasmas dynamics and composition.

Numerical Simulation and Parameter Optimization on Forming Process of Automobile Torque Box

2014 ◽  
Vol 722 ◽  
pp. 140-146
Author(s):  
Wen Juan Zhang ◽  
Long Wu ◽  
Gang Chen
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Parameter Optimization ◽  
Process Parameters ◽  
Fem Simulation ◽  
Simulation Software ◽  
Drawing Process ◽  
Forming Process ◽  
Element Simulation

In this paper the drawing process of Box-torque was simulated by Dynaform, which is FEM simulation software. The process parameters, which affected the quality of forming, were optimized by finite element simulation. The emphasis was focus on the optimization of draw-bead and BHF and data were summarized from the optimization graphs. In this simulation, lengthways draw-bead was set on the technical face for reducing or eliminating wrinkle. It was innovation difference from the usual that the draw-bead was set on binder. Finally the correctness of simulation was approved by comparing the optimization of simulation with the data of experimentation.

Investigation of Combustion Oscillations in a Lean Gas Turbine Model Combustor

2007 ◽  
Author(s):  
Olaf Diers ◽  
Denis Schneider ◽  
Melanie Voges ◽  
Peter Weigand ◽  
Christoph Hassa
Keyword(s):  
Atmospheric Pressure ◽  
Acoustic Pressure ◽  
Particle Image ◽  
Operating Conditions ◽  
Operating Point ◽  
Image Velocimetry ◽  
Different Types ◽  
Mass Flows ◽  
Combined Data

This contribution is a continuation of ASME-GT2006-90300. While still working at atmospheric pressure, the range of operating conditions was extended to more realistic reduced mass flows to reproduce the engine pressure loss and air preheat up to 700K. The thermoacoustic behaviour of the burner was mapped over that operating range. Two different types of oscillations were observed for flames anchored at the nozzle or lifted from it. Both exhibited a frequency dependence on the Strouhal number for constant reduced mass flows. For a selected operating point with the lifted flame at a preheat temperature of 600K and a reduced mass flow of 0.3kg K0.5/(s bar), the thermoacoustic behaviour of the burner was characterised by phase locked Particle Image Velocimetry as well as phase locked OH- and OH-T- LIF measurements and correlated to the acoustic pressure signal obtained by microphones. The combined data showed pulsating combustion being supported through periodic reignition of the main flame zone by a recirculating volume of hot, OH-rich gas, the cycle time being connected to the observed frequency. The characterization of the preheated operating point was completed with a heat balance investigation quantifying the non-adiabatic combustion conditions of the uncooled combustor.

Trace gas detection based on photoacoustic spectroscopy in 3-D printed gas cell

2020 ◽  
Vol 28 (4) ◽  
pp. 236-242
Author(s):  
Shenlong Zha ◽  
Hongliang Ma ◽  
Changli Zha ◽  
Xueyuan Cai ◽  
Yuanyuan Li ◽  
...  
Keyword(s):  
Photoacoustic Spectroscopy ◽  
Near Infrared ◽  
Acoustic Pressure ◽  
Resonant Cavity ◽  
Photoacoustic Signal ◽  
Trace Gas ◽  
Integration Time ◽  
Photoacoustic Cell ◽  
Normal Atmospheric Pressure ◽  
Micro Resonator

A novel photoacoustic spectroscopy gas sensor based on a micro-resonator has been developed. The photoacoustic cell was designed and fabricated using 3-D printing and the photoacoustic cell volume was compressed significantly. This design greatly reduces the time of manufacturing the micro-resonator and the weight was lighter compared to traditional cells. Furthermore, the acoustic pressure distribution in the 3-D printed photoacoustic cell was analyzed by COMSOL Multiphysics software, which indicated that the strongest acoustic pressure occurred in the middle of the resonant cavity. The performance of the sensor was evaluated by detection of CH4 at normal atmospheric pressure used a near infrared distributed feedback laser emitted at 1653 nm. The characteristic of the photoacoustic signal under different pressures was also investigated. An Allan variance shows that the 3-D printed photoacoustic spectroscopy sensor has the detection limit of 1.44 ppmv (3σ) for CH4 detection at about 200 s integration time.

Stress Analysis and Improvement of Extrusion Dies Using Combination of FEM with Taguchi Method

2015 ◽  
Vol 764-765 ◽  
pp. 143-147
Author(s):  
Kao Hua Chang ◽  
Ching Wei Shih ◽  
Gow Yi Tzou
Keyword(s):  
Taguchi Method ◽  
Principal Stress ◽  
Fem Simulation ◽  
Cobalt Content ◽  
Maximum Principal Stress ◽  
Simulation Software ◽  
Extrusion Dies ◽  
Assembly Method ◽  
Die Materials ◽  
Reference Parameters

This study aims at analyzing the influence of the maximum principal stress on Tungsten Carbide Steel die core in an extrusion die which caused the crack of die core, and then adjusts the dies assembly method in order to improve the service life of die. In this study, combining FEM simulation software with Taguchi Method L9(34) is to choose the cobalt content for die core materials, and the quantity of shrink fit while assembling the die core and die case as the reference parameters. When carrying out the simulation process, compared the changes of the maximum principal stress of the die core caused by the plastic deformation of die materials to achieve the minimum expected value as the goal be chosen the most optimal die combination. Then, the results obtained are to make dies in trial and mass-production practically; as a result, it can be achieved that the die life is improved from the original 1000pcs to 150000pcs, which is more 150 times better than before.

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