scholarly journals Effect of Laser on Double-Arc Physical Characteristics in Pulsed Laser Induced Double-TIG Welding

2021 ◽  
Author(s):  
Liming Liu ◽  
Xinkun Xu ◽  
Guomin Xu ◽  
Zhaodong Zhang
Keyword(s):  
Heat Source ◽  
High Speed ◽  
Pulsed Laser ◽  
Physical Characteristics ◽  
Particle Migration ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Horizontal Distance ◽  
Arc Plasma ◽  
Total Electron

Abstract In order to improve the energy utilization efficiency of double-TIG arc, based on the synchronous induction of pulsed laser to double-arc, the coupling-enhanced discharge phenomenon between double-arc is studied in this paper. The energy utilization efficiency of pulsed laser induced double-arc is quantitatively analyzed. The physical characteristics of coupling double-arc are studied based on high-speed camera and spectral diagnosis technology. The physical model is established to discuss the particle migration during the coupling discharge, characterizing the movement state of electrons. The results show that Dla (horizontal distance between the tungsten electrode tip and laser beam axis) has a significant effect on the energy utilization efficiency of the heat source. With the increase of Dla, there are three interaction relationships between the double-arc plasma and keyhole plasma: Mutual interference, Coupling-enhanced discharge and No interaction. A suitable Dla can realize the synchronous induction of laser to double-arc plasma, forming a coupling double-arc, the heat source has a higher energy utilization efficiency. The migration of particles in double-arc can be divided into four stages: Double-arc free discharge stage, Laser-induced initial stage, Laser-induced contraction stage and Laser-induced stable stage. Under the induction of laser, the double-arc forms a common compressed conductive channel. The energy density of coupling double-arc reaches 9.3 times that of traditional double-arc, and the total electron kinetic energy increases by 38% compared with traditional double-arc.

scholarly journals Perfect metamaterial absorber improved laser-driven flyer

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiangbo Ji ◽  
Wenzhi Qin ◽  
Xuannan Wu ◽  
Yao Wang ◽  
Fuhua Gao ◽  
...  
Keyword(s):  
Electron Temperature ◽  
High Speed ◽  
High Performance ◽  
Metal Structure ◽  
Metamaterial Absorber ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Acceleration Process ◽  
Perfect Metamaterial Absorber ◽  
New Perspective

Abstract Laser driven flyer (LDF) can drive small particles to ultrahigh speed (several km/s) by feeding pulse laser light, and exhibits giant application prospect in both of the civilian and military regions, such as the ignition of missile and spacecraft and dynamic high-pressure loading. In this work, we demonstrate a high-performance LDF by using the perfect metamaterial absorber (PMA) to improve the energy utilization efficiency of light. The designed Ag nanopillar array in anodic aluminum oxide templates (APA-AAO) were skillfully fabricated in-situ on the flyer layer surface, which can greatly reduce the reflectivity from 93% of the pure Al foil flyers to about 5% of the APA-AAO enhanced flyers. Our systematically transient analysis reveals that this ultralow reflectivity, together with the well-formed metal structure on Al foil, greatly improve both of the electron temperature and sustaining time of plasma formed in the ablating layer, and further enhances the acceleration process at both of the initial detonation wave generation stage (0–10 ns) and the following thermal expansion stage (10–200 ns). The final speed of the flyer generated in the PMA-enhanced LDF approach to 1730 m/s, which is about 1.4 times larger than that (1250 m/s) of the pure Al foil flyers. The transient electron temperature, transient flyer shadowgraph, plasma sustaining time, velocity, and accelerated velocity have been investigated systematically in this work. This PMA enhanced LDF provides an effective method for obtaining high-speed microparticles, and opens up a new perspective and guidance for designing high-performance LDF.

scholarly journals Study on Time Characteristics of Coupling Discharge in Pulsed Laser Induced Double-TIG Welding

2021 ◽  
Author(s):  
Xinkun Xu ◽  
Huanyu Yang ◽  
Liming Liu
Keyword(s):  
High Speed ◽  
Pulsed Laser ◽  
Pulse Action ◽  
Tig Welding ◽  
Duty Ratio ◽  
Regulation Mechanism ◽  
Arc Plasma ◽  
Existence Time ◽  
Arc Pressure ◽  
Marangoni Force

Abstract Based on the dynamic behavior of laser keyhole, the time characteristics of coupling discharge of heat source in pulsed laser induced double-TIG welding (LIDTW) are studied. The behaviors of arc plasma and laser keyhole were directly observed by high-speed camera and auxiliary illumination source. The physical characteristics of arc plasma were analyzed by spectrometer and arc quality analyzer. A physical model is established to reveal the regulation mechanism of time characteristics of coupling discharge. It is found that after laser pulse action the coupling discharge between keyhole plasma and double-arc plasma does not end immediately, and its time depends on the existence time of keyhole. During hybrid welding, when the combined force of arc pressure and Marangoni force can overcome the gravity, the liquid metal is forced out of the keyhole and the keyhole remains open. Improving the electron density of arc plasma and arc voltage and reducing the diameter of arc conductive channel by selecting appropriate parameters to is the key to prolong the existence time of keyhole, which is beneficial to improve the welding penetration. The coupling enhancement of double-arc electromagnetic field in LIDTW can effectively suppress keyhole backfill and increase the duty ratio of coupling discharge. When the total current intensity is 200 A, compared with laser induced single-TIG welding (LISTW), the existence time of keyhole in LIDTW increases by 77 %, the duty ratio of coupling discharge increases by 12 %, and the weld penetration increases by 29.2 %.

Characteristics of pulsed nanosecond discharge excited by compact solid-state pulse forming line at atmospheric pressure air

2021 ◽  
Author(s):  
Jie Li ◽  
Yi Liu ◽  
Xi Li ◽  
Pang Dong ◽  
Feixiang Liu ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
High Speed ◽  
Average Energy ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
High Speed Photography ◽  
Pulsed Plasma ◽  
Streamer Discharge ◽  
Equilibrium Plasma ◽  
Non Equilibrium

Abstract Non-equilibrium plasma is a promising technology for the generation of ozone and removal of exhausted fuel gases. However, applications of non-equilibrium plasma are restricted by energy utilization efficiency in many industry fields. Discharge excited by nanosecond pulsed power is regarded as one of the most efficient methods. In this study, a compact 5 stages stacked blumlein pulse forming line and photoconductive semiconductor switches-based power source was introduced to generate pulsed plasma. This compact source could achieve over 50 kV with 10.1 ns pulse width and 4.8 ns pulse rising time. Coaxial cylindrical reactor was employed to generate a pulsed streamer discharge driven by the nanosecond pulsed source in atmospheric pressure air. Electrical parameters of the streamer discharge have been obtained in this study, the instantaneous power dissipation exceeds 8 MW and the average energy consumption of each pulse exceeds 56 mJ. Experiments of high speed photography have been conducted to observe the evolution process. It can be found that streamer heads start from the central wire electrode and then head to the grounded cylinder electrode in all radial direction of the coaxial electrode. Triple wire-to-cylinder electrodes discharge shows that all the three coaxial discharges develop synchronously and symmetrically, which shows that is capable of generating large volume non-equilibrium diffusive streamer discharge plasma.

Advanced Rapid Forming Technology for Remanufacturing Engineering

2012 ◽  
Vol 271-272 ◽  
pp. 386-389
Author(s):  
Pei Jing Shi ◽  
Hong Mei Wang ◽  
Wei Zhang ◽  
Bin Shi Xu
Keyword(s):  
Heat Source ◽  
High Speed ◽  
High Density ◽  
Arc Spraying ◽  
Source Surface ◽  
Arc Plasma ◽  
Forming Technology ◽  
Laser Heat Source ◽  
Original Size ◽  
And Performance

Based on the foreign remanufacturing mode, the new remanufacturing rapid forming technology, which relies mainly on Surface Repair and Performance Improving Method has been explored and practiced. The aim of remanufacturing forming is to renew the original size of the waste components rapidly, and then improve their service performance. The advanced rapid forming technology, especially the high density heat source surface forming technology, is the important technique to carry out rapid forming. Based on the arc heat source, plasma heat source and laser heat source, three kinds of high density heat source remanufacturing forming technologies, such as high speed arc spraying forming technology, micro-arc plasma forming technology, and laser cladding forming technology, have been developed.

Regional integrated energy system schemes selection based on risk expectation and Mahalanobis-Taguchi system

2021 ◽  
pp. 1-18
Author(s):  
Jiahang Yuan ◽  
Yun Li ◽  
Xinggang Luo ◽  
Lingfei Li ◽  
Zhongliang Zhang ◽  
...  
Keyword(s):  
Energy Demand ◽  
Choquet Integral ◽  
Subjective Evaluation ◽  
Risk Attitude ◽  
Energy System ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Energy Structure ◽  
Fuzzy Measures ◽  
Integrated Energy System

Regional integrated energy system (RIES) provides a platform for coupling utilization of multi-energy and makes various energy demand from client possible. The suitable RIES composition scheme will upgrade energy structure and improve integrated energy utilization efficiency. Based on a RIES construction project in Jiangsu province, this paper proposes a new multi criteria decision-making (MCDM) method for the selection of RIES schemes. Because that subjective evaluation on RIES schemes benefit under criteria has uncertainty and hesitancy, intuitionistic trapezoidal fuzzy number (ITFN) which has the better capability to model ill-known quantities is presented. In consideration of risk attitude and interdependency of criteria, a new decision model with risk coefficients, Mahalanobis-Taguchi system and Choquet integral is proposed. Firstly, the decision matrices given by experts are normalized, and then are transformed to minimum expectation matrices according to different risk coefficients. Secondly, the weights of criteria from different experts are calculated by Mahalanobis-Taguchi system. Mobius transformation coefficients based on interaction degree are to calculate 2-order additive fuzzy measures, and then the comprehensive weights of criteria are obtained by fuzzy measures and Choquet integral. Thirdly, based on group decision consensus requirement, the weights of experts are obtained by the maximum entropy and grey correlation. Fourthly, the minimum expectation matrices are aggregated by the intuitionistic trapezoidal fuzzy Bonferroni mean operator. Thus, the ranking result according to the comparison rules using the minimum expectation and the maximum expectation is obtained. Finally, an illustrative example is taken in the present study to make the proposed method comprehensible.

scholarly journals Acute Effects of Handheld Loading on Standing Broad Jump in Youth Athletes

2021 ◽  
Vol 18 (9) ◽  
pp. 5046
Author(s):  
Wei-Hsun Tai ◽  
Ray-Hsien Tang ◽  
Chen-Fu Huang ◽  
Shin-Liang Lo ◽  
Yu-Chi Sung ◽  
...  
Keyword(s):  
High Speed ◽  
Center Of Mass ◽  
Reaction Force ◽  
Sampling Rate ◽  
Random Order ◽  
Horizontal Distance ◽  
Acute Effects ◽  
Vertical Ground Reaction Force ◽  
Strength And Conditioning ◽  
Peak Knee

The study aimed to investigate the acute effects of handheld loading on standing broad jump (SBJ) performance and biomechanics. Fifteen youth male athletes (mean age: 14.7 ± 0.9 years; body mass: 59.3 ± 8.0 kg; height: 1.73 ± 0.07 m) volunteered to participate in the study. Participants were assigned to perform SBJ with and without 4 kg dumbbells in a random order. Kinematic and kinetic data were collected using 10 infrared high-speed motion-capture cameras at a 250 Hz sampling rate and two force platforms at a 1000 Hz sampling rate. A paired t-test was applied to all variables to determine the significance between loading and unloading SBJs. Horizontal distance (p < 0.001), take-off distance (p = 0.001), landing distance (p < 0.001), horizontal velocity of center of mass (CoM; p < 0.001), push time (p < 0.001), vertical impulse (p = 0.003), and peak horizontal and vertical ground reaction force (GRF; p < 0.001, p = 0.017) were significantly greater in loading SBJ than in unloading SBJ. The take-off vertical velocity of CoM (p = 0.001), take-off angle (p < 0.001), peak knee and hip velocity (p < 0.001, p = 0.007), peak ankle and hip moment (p = 0.006, p = 0.011), and peak hip power (p = 0.014) were significantly greater in unloading SBJ than in loading SBJ. Conclusions: Acute enhancement in SBJ performance was observed with handheld loading. The present findings contribute to the understanding of biomechanical differences in SBJ performance with handheld loading and are highly applicable to strength and conditioning training for athletes.

Evaluation of Energy Efficiency for a CCHP System With Available Microturbine

2007 ◽  
Author(s):  
H. X. Liang ◽  
Q. W. Wang
Keyword(s):  
Gas Turbine ◽  
Waste Heat ◽  
Energy System ◽  
Primary Energy ◽  
Economic Benefits ◽  
Optimal Operation ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Energetic Efficiency ◽  
Efficiency Evaluation

This paper deals with the problem of energy utilization efficiency evaluation of a microturbine system for Combined Cooling, Heating and Power production (CCHP). The CCHP system integrates power generation, cooling and heating, which is a type of total energy system on the basis of energy cascade utilization principle, and has a large potential of energy saving and economical efficiency. A typical CCHP system has several options to fulfill energy requirements of its application, the electrical energy can be produced by a gas turbine, the heat can be generated by the waste heat of a gas turbine, and the cooling load can be satisfied by an absorption chiller driven by the waste heat of a gas turbine. The energy problem of the CCHP system is so large and complex that the existing engineering cannot provide satisfactory solutions. The decisive values for energetic efficiency evaluation of such systems are the primary energy generation cost. In this paper, in order to reveal internal essence of CCHP, we have analyzed typical CCHP systems and compared them with individual systems. The optimal operation of this system is dependent upon load conditions to be satisfied. The results indicate that CCHP brings 38.7 percent decrease in energy consumption comparing with the individual systems. A CCHP system saves fuel resources and has the assurance of economic benefits. Moreover, two basic CCHP models are presented for determining the optimum energy combination for the CCHP system with 100kW microturbine, and the more practical performances of various units are introduced, then Primary Energy Ratio (PER) and exergy efficiency (α) of various types and sizes systems are analyzed. Through exergy comparison performed for two kinds of CCHP systems, we have identified the essential principle for high performance of the CCHP system, and consequently pointed out the promising features for further development.

Nanowire-based zinc-doped tin oxide microtubes for enhanced solar energy utilization efficiency

2017 ◽  
Vol 43 (9) ◽  
pp. 6822-6830 ◽  
Author(s):  
Wutao Mao ◽  
Zhengdao Li ◽  
Keyan Bao ◽  
Kaijun Zhang ◽  
Weibo Wang ◽  
...  
Keyword(s):  
Solar Energy ◽  
Tin Oxide ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Solar Energy Utilization

Carbon Emission of Mining Industry’s Energy Consumption in Heilongjiang Province

2015 ◽  
Vol 1092-1093 ◽  
pp. 1597-1600
Author(s):  
Zhong Hua Wang ◽  
Xin Ye Chen
Keyword(s):  
Energy Consumption ◽  
Carbon Emissions ◽  
Carbon Emission ◽  
Industrial Structure ◽  
Mining Industry ◽  
Calculation Model ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Heilongjiang Province ◽  
Low Carbon

The need to reduce carbon emission in Heilongjiang Province of China is urgent challenge facing sustainable development. This paper aims to make explicit the problem-solving of carbon emission to find low carbon emission ways. According to domestic and foreign literatures on estimating and calculating carbon emissions and by integrating calculation methods of carbon emissions, it was not possible to consider all of the many contributions to carbon emissions. Calculation model of carbon emissions suitable to this paper is selected. The carbon emissions of energy consumption in mining industry are estimated and calculated from 2005 to 2012, and the characteristics of carbon emission are analyzed at the provincial level. It makes the point that carbon emissions of energy consumption in mining industry can be reduced when we attempt to alter energy consumption structure, adjust industrial structure and improve energy utilization efficiency.

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