Surface Melting, Spallation, and Stresses Induced in Metals by Pulsed Electron Beam Heating

1971 ◽  
Vol 38 (2) ◽  
pp. 363-370 ◽  
Author(s):  
L. W. Woodruff ◽  
W. H. Giedt ◽  
J. L. Hesse
Keyword(s):  
Electron Beam ◽  
Equation Of State ◽  
Target Surface ◽  
Surface Melting ◽  
Phase Region ◽  
Internal Stresses ◽  
Two Phase ◽  
One Dimensional ◽  
Pulsed Electron Beam ◽  
Specific Objective

The present study was undertaken to investigate the applicability of one-dimensional computer programs for predicting the response of materials exposed to rapid surface heating produced by a pulsed electron beam. A specific objective was to determine modifications necessary to account for surface melting and spall. Measured values of mass loss, impulse, and internal stresses in lead and gold were satisfactorily predicted using a one-dimensional finite-difference program which simultaneously solved the conservation equations and a hydrodynamic equation of state. Required program modifications included: (a) specifying spall to occur to the depth below the target surface at which the energy deposited was sufficient to initiate melting, and (b) revising the equation of state for the material in the two-phase region.

A Simulation of the Liquid Shock and Cavitation Based on a Multi-Equation Model

2016 ◽  
Vol 13 (04) ◽  
pp. 1641010
Author(s):  
Yang-Yao Niu
Keyword(s):  
Equation Of State ◽  
Blunt Body ◽  
Equation Model ◽  
Test Cases ◽  
Riemann Solver ◽  
Temperature Dependent ◽  
Two Phase ◽  
One Dimensional ◽  
Condensation Shock ◽  
Multi Phase

In this paper, an unsteady preconditioning formulation for multi-phase flows with arbitrary equation of state based on the approximated Riemann solver is developed for multi-phase flows at all speed. This paper considers a homogeneous two-phase multi-equation mixture model with the assumption of kinematics and thermodynamics equilibriums. The thermodynamics behaviors of liquid phase, vapor phase and their phase transitional process are described by a temperature-dependent hybrid equation of state. Benchmark test cases, including one-dimensional (1D) condensation shock in the cavitated nozzle and two-dimensional (2D) cavitated blunt body problem, demonstrate accurate capturing of interfaces, shock waves and cavitation zones.

Scanning Electron-Beam Dielectric Microscopy for the Temperature Coefficient Distribution of Dielectric Materials

2001 ◽  
Vol 700 ◽  
Author(s):  
Yasuo Cho
Keyword(s):  
Electron Beam ◽  
Temperature Coefficient ◽  
Dielectric Materials ◽  
Two Phase ◽  
Sem Images ◽  
Pulsed Electron Beam ◽  
Scanning Electron Beam ◽  
Microscopy Technique ◽  
Coefficient Distribution ◽  
Scanning Electron

AbstractStudies on scanning electron-beam dielectric microscopy (SEDM) are reported. This microscopy technique is used for determining the temperature coefficient distribution of dielectric materials using an electron-beam as a heat source instead of a light beam as in photothermal dielectric microscopy. This microscopy technique, which has the ability to simultaneously observe SEM images and the material composition by EPMA, has a resolution better than that of photothermal dielectric microscopy. To demonstrate the usefulness of this technique, the two-dimensional image of a two-phase composite ceramic composed of TiO2 and Bi2Ti4O11 is measured. To shorten a measurement time, a new type of SEDM for measuring the real time transient response caused by a single pulsed electron-beam is also successfully developed. Finally, a quantitative measurement method of temperature coefficient is also developed.

scholarly journals Structure and properties of high-chromium steel irradiated with a pulsed electron beam and nitrided in a low-pressure gas discharge plasma

2021 ◽  
Vol 2064 (1) ◽  
pp. 012043
Author(s):  
Y Ivanov ◽  
E Petrikova ◽  
A Teresov ◽  
S Lykov ◽  
O Tolkachev ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
Electron Beam ◽  
Low Pressure ◽  
Developed Countries ◽  
Gas Discharge ◽  
Iron Nitride ◽  
Complex Method ◽  
Two Phase ◽  
Pulsed Electron Beam

Abstract Ion-plasma saturation of the surface of machine parts and mechanisms with gas elements (nitrogen, oxygen, carbon) is currently one of the most effective and widely used methods of surface hardening of metal products for various purposes in the industry of developed countries. The aim of this research is to develop a complex method for modifying the surface layer of AISI 310 steel, combining irradiation with an intense pulsed electron beam and subsequent nitriding in the plasma of a low-pressure gas discharge. As a result of the studies performed, the optimal parameters of modification were revealed, which make it possible to increase the hardness of the surface layer of steel by more than 11 times, relative to the hardness of the initial material, and 8 times, relative to the hardness of steel irradiated with a pulsed electron beam. In this case, the wear resistance of the steel exceeds the wear resistance of the original and irradiated material by more than 100 times. It has been established that the high strength and tribological properties of the modified steel are due to the formation of a two-phase (iron nitride and chromium nitride) layered nanoscale structure in the surface layer.

Heat and Mass Transports in Porous Wicks Driven by a Gas-Phase Diffusion Flame

2005 ◽  
Author(s):  
Mandhapati P. Raju ◽  
James S. T’ien
Keyword(s):  
Gas Phase ◽  
Diffusion Flame ◽  
Capillary Rise ◽  
Phase Region ◽  
Standoff Distance ◽  
Dimensional System ◽  
Liquid Region ◽  
Two Phase ◽  
One Dimensional ◽  
Porous Wick

A one dimensional stagnation point diffusion flame stabilized next to a porous wick is studied using a numerical model. The bottom end of the one-dimensional wick is dipped inside a liquid fuel (ethanol) reservoir. The liquid is drawn towards the surface of the wick through capillary action against gravity. The model combines heat and mass transfer equations in the porous media with phase change and gas-phase combustion equations to investigate steady-state flow structure in the porous wick and flame characteristics in the gas phase. In one-dimensional system, the only steady solution in the porous wick that is stable is found to be in the funicular regime. There are two regions in the wick: a vapor-liquid two-phase region near the surface exposed to the flame and a purely liquid region deep inside the wick. The physics behind the two-phase flow driven by capillarity and evaporation has been studied in detail. The coupling between the flame and the porous transport involves three different length scales: flame standoff distance, wick height above the reservoir and capillary rise. Attempt is made to study the effect of the non-dimensional numbers that contains these scales. In the limit of fast chemical kinetics (large Damkohler number), the computed results depend only on two non-dimensional ratios: the ratio of wick height to capillary rise and the ratio of wick height to flame standoff distance. Thus, a simplified similitude has been identified.

scholarly journals Modification of the Redlich-Kwong-Aungier Equation of State to Determine the Degree of Dryness in the CO2 Two-phase Region

2021 ◽  
Vol 24 (4) ◽  
pp. 17-27
Author(s):  
Hanna S. Vorobieva ◽  
Keyword(s):  
Experimental Data ◽  
Equation Of State ◽  
Gas Phase ◽  
Saturated Vapor ◽  
Phase Region ◽  
Working Fluid ◽  
Two Phase ◽  
Real Gas ◽  
Liquid Phases ◽  
Good Agreement

The degree of dryness is the most important parameter that determines the state of a real gas and the thermodynamic properties of the working fluid in a two-phase region. This article presents a modified Redlich-Kwong-Aungier equation of state to determine the degree of dryness in the two-phase region of a real gas. Selected as the working fluid under study was CO2. The results were validated using the Span-Wanger equation presented in the mini-REFPROP program, the equation being closest to the experimental data in the CO2 two-phase region. For the proposed method, the initial data are temperature and density, critical properties of the working fluid, its eccentricity coefficient, and molar mass. In the process of its solution, determined are the pressure, which for a two-phase region becomes the pressure of saturated vapor, the volumes of the gas and liquid phases of a two-phase region, the densities of the gas and liquid phases, and the degree of dryness. The saturated vapor pressure was found using the Lee-Kesler and Pitzer method, the results being in good agreement with the experimental data. The volume of the gas phase of a two-phase region is determined by the modified Redlich-Kwong-Aungier equation of state. The paper proposes a correlation equation for the scale correction used in the Redlich-Kwongda-Aungier equation of state for the gas phase of a two-phase region. The volume of the liquid phase was found by the Yamada-Gann method. The volumes of both phases were validated against the basic data, and are in good agreement. The results obtained for the degree of dryness also showed good agreement with the basic values, which ensures the applicability of the proposed method in the entire two-phase region, limited by the temperature range from 220 to 300 K. The results also open up the possibility to develop the method in the triple point region (216.59K-220 K) and in the near-critical region (300 K-304.13 K), as well as to determine, with greater accuracy, the basic CO2 thermodynamic parameters in the two-phase region, such as enthalpy, entropy, viscosity, compressibility coefficient, specific heat capacity and thermal conductivity coefficient for the gas and liquid phases. Due to the simplicity of the form of the equation of state and a small number of empirical coefficients, the obtained technique can be used for practical problems of computational fluid dynamics without spending a lot of computation time.

Pulsed electron beam surface melting of CoCrMo alloy for biomedical applications

Wear ◽  
2013 ◽  
Vol 301 (1-2) ◽  
pp. 250-256 ◽  
Author(s):  
J.C. Walker ◽  
R.B. Cook ◽  
J.W. Murray ◽  
A.T. Clare
Keyword(s):  
Electron Beam ◽  
Biomedical Applications ◽  
Surface Melting ◽  
Cocrmo Alloy ◽  
Pulsed Electron Beam ◽  
Beam Surface

Steady-State Network Thermofluid Models of Loop Heat Pipes

2007 ◽  
Author(s):  
Nima Atabaki ◽  
Nirmalakanth Jesuthasan ◽  
B. Rabi Baliga
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Steady State ◽  
Phase Region ◽  
Vapor Transport ◽  
Two Phase ◽  
Liquid Transport ◽  
One Dimensional ◽  
Flow And Heat Transfer ◽  
Transport Line

A loop heat pipe (LHP) with one evaporator, a vapor-transport line, a single condenser, a liquid-transport line, and a compensation chamber is considered. The evaporator is an internally grooved circular pipe, with an annular wick installed on its inner surface. The wick is made of sintered powder metal. The condenser is a horizontal tube that is fitted with excellent thermal contact inside a metallic sleeve that is immersed in a constant-temperature bath maintained at a fixed sink temperature. Two different network thermofluid models of this LHP operating under steady-state conditions are presented. In the first (basic) model, quasi one-dimensional mathematical models of the fluid flow and heat transfer in each of the elements of the LHP are used; the pressure drop in the two-phase region of the condenser is ignored; and a relatively simple correlation is used to model the heat transfer in the two-phase region of the condenser. In the second (segmented) model, quasi one-dimensional control volumes or cells are used for the simulation of fluid flow and heat transfer in the vapor-transport line, the condenser, and the liquid-transport line, in order to better account for the variation of fluid properties and the quality (in two-phase regions); and the pressure drops in the two-phase regions are accounted for. The working fluid considered in this investigation is ammonia, but the proposed models can be used with any suitable fluid. Results pertaining to the LHP performance for a range of operating conditions are presented. Some of these results are compared to corresponding results of an earlier experimental investigation in the literature: good agreement is obtained with both models.

scholarly journals Layer structure, plasma jet, and thermal dynamics of Cu target irradiated by relativistic pulsed electron beam

2009 ◽  
Vol 27 (3) ◽  
pp. 497-509 ◽  
Author(s):  
Limin Li ◽  
Lie Liu ◽  
Guoxin Cheng ◽  
Qifu Xu ◽  
Xingjun Ge ◽  
...  
Keyword(s):  
Electron Beam ◽  
Energy Density ◽  
Relativistic Electron ◽  
Cross Section ◽  
Relativistic Electron Beam ◽  
Layer Structure ◽  
Target Surface ◽  
Plasma Jet ◽  
Thermal Dynamics ◽  
Pulsed Electron Beam

AbstractThis paper, based on a relativistic electron-beam accelerator with inductive energy accumulation, investigates the layer structure, plasma jet, and thermal dynamics of Cu target under the irradiation of pulsed electron beam (~350 kV, ~4 kA, ~300 ns). A description of a relativistic electron beam source with a carbon fiber cathode is presented. After the electron-beam irradiation at ~13 J/cm2energy density, microcraters with 0.5–1 µm diameter appeared on the target surface, and the target cross section is characterized by multilayer structures with a ~20 µm thickness melting layer and a cellular layer. Further, it was found that the carbon content increased significantly not only on the target surface but also on the cross section. The gas liberation per pulse induced by electron beam is analyzed. A good agreement between the experimental and calculated perveances was observed, with the exception at the end of the accelerating pulse possibly due to the participation of ion flow from the anode target. In the pulsed emission, there existed material transfer from anode to cathode, which is observed by the identification of elemental compositions on cathode surface. As the beam energy is deposited on target surface, the anode plasma jet is generated, and expands toward the cathode at a velocity of ~3 cm/μs. By solving the one-dimensional heat equation, 109K/s heating rate and 107K/m temperature gradient can be obtained. After the heating of pulsed electron beam, the thermal conduction is dominant, with a cooling rate on the order of 107 K/s. The relativistic electron beam sources may provide a potential development for target experiments and high energy density physics.

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