Ion heat transport in electron cyclotron resonance heated L-mode plasma on the T-10 tokamak

Anomalous ion heat transport is analyzed in the T-10 tokamak plasma heated with electron cyclotron resonance heating(ECRH) in second-harmonic extra-ordinary mode. Predictive modeling with empirical scaling for Ohmical heat conductivity shows that in ECRH plasmas the calculated ion temperature could be overestimated, so an increase of anomalous ion heat transport is required. To study this effect two scans are presented: over the EC resonance position and over the ECRH power. The EC resonance position varies from the high-field side to the low-field side by variation of the toroidal magnetic field. The scan over the heating power is presented with on-axis and mixed ECRH regimes. Discharges with high anomalous ion heat transport are obtained in all considered regimes. In these discharges the power balance ion heat conductivity exceeds the neoclassical level by up to 10 times. The high ion heat transport regimes are distinguished by three parameters: the ratio Te/Ti, the normalized electron density gradient R/■, and the ion–ion collisionality νii~*. The combination of high Te/Ti, high νii~*, and R/■=6-10 results in values of normalized anomalous ion heat fluxes up to 10 times higher than in the low transport scenario.

Novel Analysis of Two Kinds Hybrid Models in Ferro Martial Inserting Variable Lorentz Force Past a Heated Disk:An Implementation of Finite Element Method

In this article,the rheology of Ferro-fluid over an axisymmetric heated disc with a variable magnetic field by considering the dispersion of hybrid nanoparticles is considered.The flow is assumed to be produced by the stretching of a rotating heated disc.The contribution of variable thermophysical properties is taken to explore themomentum,mass and thermal transportation.The concept of boundary layermechanismis engaged to reduce the complex problem into a simpler one in the form of coupled partial differential equations system.The complex coupled PDEs are converted into highly nonlinear coupled ordinary differential equations system(ODEs)and the resulting nonlinear flow problem is handled numerically.The solution is obtained via finite element procedure(FEP)and convergence is established by conducting the grid-independent survey.The solution of converted dimensionless problem containing fluid velocity,temperature and concentration field is plotted against numerous involved emerging parameters and their impact is noted.From the obtained solution,it is monitored that higher values of magnetic parameter retard the fluid flow and escalating values of Eckert number results in to enhance temperature profile.Ferro-fluid flow and heat energy for the case of the Yamada Ota hybrid model are higher than for the case of the Hamilton Crosser hybrid model.Developing a model is applicable to the printing process,electronic devices,temperature measurements,engineering process and food-making process.The amount of mass species is reduced vs.incline impacts of chemical reaction and Schmidt parameter.

Thermo-diffusion impact on immiscible flow characteristics of convectively heated vertical two-layered Baffle saturated porous channels in a suspension of nanoparticles:an analytical study

The heat and mass transfer of two immiscible fluids in an inclined channel with thermal diffusion,vicious,and Darcy dissipation is studied.The first region consists of a clear fluid,and the second one is filled with a nanofluid saturated with a porous medium.The behaviors of Cu-H_(2)O,In-H_(2)O,and Au-H_(2)O nanofluids are analyzed.The transport properties are assumed to be constant.The coupled non-linear equations of the flow model are transformed into the dimensionless form,and the solutions for the velocity,temperature,and concentration are obtained by the regular perturbation technique.Investigations are carried out on the flow characteristics for various values of the material parameters.The results show that the velocity and temperature of the fluids enhance with the thermal Grashof number,solutal Grashof number,and Brinkman number while decrease with the porosity parameter and solid volume fraction.

Numerical Study of Natural Convective Heat Transfer in an Air Filled Square Cavity Heated from Below and Symmetrically Cooled from the Sides with a Partition in the Hot Wall

A two-dimensional numerical study of laminar natural convection in a square enclosure filled with air with a wall partially heated on the bottom is presented.The heat source is located on the lower wall with different heated widths varied from 20 to 80%(ε=0.2–0.8)of the total width of the lower wall and different heights h=H/4 and H/2 of the partition.The effect of the partition height on the main system dynamics is investigated through solution of the two-dimensional Navier-Stokes equations and the energy equation by means of a finite volume method based on the SIMPLE algorithm.The influence of the Rayleigh number(Ra=10^(3) to 10^(6))and the hot wall length is also examined.It is shown that the average Nusselt number grows whenεincreases and when h decreases.For a given value ofεand h,the average Nusselt number increases as Ra increases.It is concluded that the partition height causes a decrease in the average Nusselt number.

Performance evaluation of two types of heated cables for distributedtemperature sensing-based measurement of soil moisture content

Distributed temperature sensing(DTS)using heated cables has been recently developed for distributed monitoring of in-situ soil moisture content.In this method,the thermal and electrical properties of heated cables have a significant influence on the measurement accuracy of soil moisture content.In this paper,the performances of two heated cables,i.e.the carbon-fiber heated cable(CFHC)and the metalnet heated cable(MNHC),are studied in the laboratory.Their structures,uniformity in the axial direction,measurement accuracy and suitability are evaluated.The test results indicate that the MNHC has a better uniformity in the axial direction than CFHC.Both CFHC and MNHC have high measurement accuracy.The CFHC is more suitable for short-distance measurement(500 m),while the MNHC can be used for longdistance measurement(>500 m).

A distributed measurement method for in-situ soil moisture content by using carbon-fiber heated cable

Moisture content is a fundamental physical index that quantifies soil property and is closely associatedwith the hydrological, ecological and engineering behaviors of soil. To measure in-situ soil moisturecontents, a distributed measurement system for in-situ soil moisture content （SM-DTS） is introduced.The system is based on carbon-fiber heated cable （CFHC） technology that has been developed to enhancethe measuring accuracy of in-situ soil moisture content. Using CFHC technique, a temperature characteristicvalue （Tt） can be defined from temperatureetime curves. A relationship among Tt, soil thermalimpedance coefficient and soil moisture content is then established in laboratory. The feasibility of theSM-DTS technology to provide distributed measurements of in-situ soil moisture content is verifiedthrough field tests. The research reported herein indicates that the proposed SM-DTS is capable ofmeasuring in-situ soil moisture content over long distances and large areas.

MICROSTRUCTURE ANALYSIS AND MECHANICAL PROPERTIES OF Zn-Al ALLOY ROD PRODUCED BY HEATED MOLD CONTINUOUS CASTING

The new technology of continuous casting by heated mold was used to produce directional solidification ZA alloy lines to eliminate the inter defects of these lines and increase their mechanical properties. The results are as follows: (1) The microstruc-ture of the ZA alloy lines is the parallel directional dendritic columnar crystal. Every dendritic crystal of eutectic alloy ZA5 was composed of many layer eutectic β and η phases. The micro structure of hypereutectic ZA alloys is primary dendritic crystal and interdendritic eutectic structure. The primary phase of ZA8 and ZA12 is β, among them, but the primary phase of ZA22 and ZA27 is a. (2) Through the test to the as-cast ZA alloy lines made in continuous casting by heated mold, it is found that the tensile strength and hardness increase greatly, but the elongation decreases. With the increase of aluminum amount from ZA 5 to ZA 12, ZA22 and ZA27, the tensile strength increases gradually. ZA27 has the best comprehensive mechanical properties in these four kinds of ZA alloys. (3) Heat treatment can decrease the dendritic segregation and improve the elongation of ZA alloy, but make their strength decrease slightly.

Thermal conductivity of dense hcp iron:Direct measurements using laser heated diamond anvil cell

Thermal conductivity(k)of iron is measured up to about 134 GPa.The measurements are carried out using the single sided laser heated diamond anvil cell,where the power absorbed by a Fe metal foil at hotspot is calculated using a novel thermodynamical method.Thermal conductivity of fee(γ)-Fe increases up to a pressure of about46 GPa.We find thermal conductivity values in the range of 70-80 Wm-1K-1(with an uncertainty of 40%),almost constant with pressure,in the hcp(e)phase of Fe.We attribute the pressure independent k above 46 GPa to the strong electronic correlation effects driven by the electronic topological transition(ETT).We predict a value of thermal conductivity ofε-Fe of about 40±16 Wm-1K-1 at the outer core of Earth.

A modified soil water content measurement technique using actively heated fiber optic sensor

Soil water content measurement is critical in practical engineering.The actively heated fiber Bragg grating optic sensor(FBGS)has great potential of multi-point measurement for soil water content measurement in field.In this study,the effect of heating time on the measurement accuracy is discussed,and modifications are made for actively heated fiber optic(AHFO)sensors.The results demonstrate that if an integration data analysis method is used,the accuracy and reliability of soil water content measurement with AHFO sensors will be improved.Both a short fiber length and a short-term heating pattern are effective and can help to reduce soil disturbance.With the proposed integration method,a short heating time is guaranteed for measuring the soil water content.Such improvements will reduce the thermal disturbance to soil sample and improve the reliability of measurement.

Absorption Measurement of Radiatively-Heated Low-z Mixture

High-resolution transmission spectra of radiatively-heated low-z C10H16O6 plasma have been measured on‘Xingguang II’laser facility by using flat field grating spectrometer.Absorption lines of oxygen and carbon ions in the region of 1.6 to 5.0 nm have been observed clearly and identified.Using the unresolved transition array model,we also calculated the transmission spectra of C10H16O6 plasma.The measured transmission spectrum has been compared with the calculated ones.

Sawtooth Activity in Ohmically Heated Plasma on HT-7 Tokamak

Sawtooth activity on HT-7 tokamak has been investigated experimentally mainly by using soft x-ray diode array and magnetic probes. Their behaviors and occurrences are correlated closely to the discharge conditions: the electron density Ne, the electron temperature Te, the safety factor qa on plasma boundary and wall condition etc. When central line-averaged electron density Ne(0) is over 2.0×1013cm-3 , major sawtooth activity emerges with a period of up to 6.5 ms and a fluctuation amplitude of up to 2-30 % of SXR radiation signal. In some cases such as the safety factor between 4.2-4.7 and Zeff=3.0-6.0, a monster sawtooth activity often emerges without apparent deterioration of plasma confinement and without major disruption. During these events, abundant MHD phenomena are observed including partial sawtooth oscillations. In this paper, the observed sawtooth behaviors and their dependence on the and their dependence density Ne and wall condition in ohmically heated plasma are introduced, the results are discussed and presented.

Study on microstructures and properties of preheated flash butt welded SW400 steel joints

Under the spirit of sustainable development, ‘lightweight’ has been gradually included into the vehicle design criterion by many manufacturers and used in automobile production. Following this trend, domestic wheel suppliers also begin to study the technology of lightweight wheel. One way to achieve this goal is improving strength grade of the steel and optimizing the structure design in the field of steel wheels. But there are a few problems in flash butt welding process in the application of high strength steel, leading to high rejection rates. SW400 steel is a special high strength wheel steel developed by Benxi Steel. Taking SW400 steel as the research material, this article studys the feasibility of improving the properties of rim flash butt welded joints by adding preheating process.

Relationships between the surface quality of a single crystal copper ingot and the process parameters of a heated mould continuous casting method

The relationships between the surface quality of a single crystal copper ingot and the process parameters of heated mould continuous casting method were studied experimentally using our own design of horizontal heated mould continuous casting apparatus, and the mechanism by which process parameters affect the surface quality of a single crystal copper ingot is analyzed in the present paper. The results show that the process parameters affect the surface quality of a pure copper ingot by affecting the position of the liquid-solid interface in the mould. The position of the liquid-solid interface in the mould must be controlled carefully within an appropriate range, which is determined through a series of experiments, in order to gain a single crystal copper ingot with good surface quality.

Effect of Hartmann Number on Free Convective Flow of MHD Fluid in a Square Cavity with a Heated Cone of Different Orientation

This paper presents the effect of magnetic field, indicated by Hartmann number (Ha), on the free convective flow of Magneto-hydro-dynamic (MHD) fluid in a square cavity with a heated cone of different orientation. Although similar studies abound, the novelty of this work lies in the presence of the heated cone, whose orientation is varied at different angles. The mathematical model includes the system of governing mass, momentum and energy equations. The system is solved by finite element method. The calculations are performed for Prandtl number Pr = 0.71;the Rayleigh number Ra = 10, 1000, 100,000;and for Hartmann number Ha = 0, 20, 50, 100. The results are illustrated with streamlines, velocity profiles and isotherms. From the results, it is found that for the present configuration, magnetic field (Hartmann number) has no effect on the shape of the streamlines for low Rayleigh numbers. However, for high values of Ra, the effect of Ha becomes quite visible. Magnetic field affects the flow by retarding the fluid movement, and thus affects convective heat transfer. At low Ra, the fluid movement and heat transfer rate are already slowing, thus impressing a magnetic field does not produce much effect. At high Ra, fluid particles move at high velocity and change the stream lines, in absence of any magnetic force. Impressing magnetic field in this situation produced noticeable effect by slowing down the fluid movement and changing the streamlines back to low Ra situations. It is noted that a combination of low Ra with zero or low Ha produces similar effects with the combination of high Ra and high Ha. It can be concluded that with increasing Ha, heat transfer mode in MHD fluid gradually changes toward conduction from convection. It can be surmised that sufficiently large Ha can potentially stop the fluid movement altogether. In that case, heat transfer would be fully by conduction.

Two-Dimensional Simulation of the Navier-Stokes Equations for Laminar and Turbulent Flow around a Heated Square Cylinder with Forced Convection

Few studies jointly investigate thermal and turbulent effects. In general, these subjects are treated separately. The purpose of this paper is to use the Immersed Boundary Method (IBM) coupled with the Virtual Physical Model (VPM) to investigate incompressible two-dimensional Newtonian flow around a heated square cylinder at constant temperature on its surface with forced convection and turbulence. The VPM model dynamically evaluates the force that the fluid exerts on the immersed surface and the thermal exchange between both in the Reynolds numbers (Re) window 40 ≤ Re ≤ 5×103 . For simulations of turbulence the Smagorinsky and Spalart-Allmaras models are used. The first model uses the Large Eddy Simulation (LES) methodology and is based on the local equilibrium hypothesis for small scales associated with the Boussinesq hypothesis, such that the energy injected into the spectrum of the turbulence balances the energy dissipated by convective effects. The second model uses the concept Unsteady Reynolds Averaged Navier-Stokes Equations (URANS), with only one transport equation for turbulent viscosity, being calibrated in pressure gradient layers. The goal of this work is to analyse the combination of the heat-transfer phenomena with the turbulence for the thermo-fluid-structure interaction in a square cylinder. For this, it was developed a C/C++ code that requires low computational costs in regards to memory and computer facilities. It is observed that, with the increase of the Reynolds number, an increase of the drag coefficient occurs, as well as reinforces the influence of the pressure distribution downstream of the cylinder, which is strongly influenced by the formation and detachment of vortices on the upper and lower sides of the square cylinder.

CONVECTIVE HEAT TRANSFER CHARACTERISTICS OF GAS IMPINGEMENT ON SMALL HEATED DEVICE IN LIQUID COOLANT BATH

Heat transfer characteristics of a small heated device have been investigated in a liquid bath with gas jetimpingement as function of gas flow rate,coolant temperature,liquid phsicochemical properties,heat flux,heat source size,ambient pressure and the distance between jet and heated wall.The experimental results show that the agitation of liquid caused by gas jet bubbles increases greatly therate of heat transfer,and the evaporation of coolant near the wall,which was due to the concentration differencebetween gas-liquid interface and bulk gas phase,gives additional enhancement of heat transfer.The rate ofevaporation related to the bubble growth was mathematically formulated.By using the simultaneous heat and mass transfer model,the convective heat transfer coefficient and masstransfer coefficient can be deduced from the experimental results.In addition,the local heat transfer coefficient and the distribution of evaporation heat flux on the smallheated surface are investigated mathematically and experimentally.

Monster Sawtooth Activity in Ohmically Heated HT-7 Plasma

Experimental properties of monster sawtooth activities in ohmic HT-7 plasma are presented in this paper. The monster sawtooth activities belong to global fluctuations and are characterized with a series of large core collapses on SXR intensity traces with a long period, a large amplitude fluctuation and a large inversion radius. However, they emerge without apparent deterioration of plasma confinement and without major plasma disruption. During the events, long partial sawtooth collapses and abundant MHD phenomena are also observed.

Experiments and simulations of isochorically heated warm dense carbon foam at the Texas Petawatt Laser

An experimental and simulation study of warm dense carbon foams at ambient density(ne∼10^(21) cm^(−3))is presented.This study of isochorically heated foams is motivated by their potential application in carbon-atmosphere white-dwarf envelopes,where there are modeling uncertainties due to the equation of state.The foams are heated on an approximately picosecond time scale with a laser-accelerated proton beam.The cooling and expansion of the heated foams can be modeled with appropriately initialized radiation-hydrodynamics codes;xRAGE code is used in this work.The primary experimental diagnostic is the streaked optical pyrometer,which images a narrow band of radiation from the rear surface of the heated material.Presented are xRAGE modeling results for both solid aluminum targets and carbonized resorcinol-formaldehyde foam targets,showing that the foam appears to cool slowly on the pyrometer because of partial transparency.So that simulations of cooling foam are processed properly,it is necessary to account for finite optical depth in the photosphere calculation,and the methods for performing that calculation are presented in depth.

Process Parameters of Manufacturing Single Crystal Copper by Heated Mold Continuous Casting

The effect of process parameters on the surface quality of single crystal copper ingot was studied through experiment with a self-designed horizontal heated mould continuous casting apparatus,and the mechanism was analyzed.The results show that the process parameters affect the surface quality of pure copper ingot by affecting the position of the liquid-solid interface in the mould.The position of the liquid-solid interface in the mould must be controlled carefully in an appropriate range determined through experiments in order to gain a single crystal copper ingot with a high surface quality.

Evaluation of Energy Efficiency Performance of Heated Windows

Fenestration systems are widely used across the world.There is expansive research on window configurations,frames,and glazing technology,but not enough research has been published on reducing window heat loss through heat application to a pane.The presented study attempted to evaluate the performance of heated windows by developing an experimental setup to test a window at various temperatures by varying the power input to thewindow.Heated double pane window was installed in an insulated box.Atemperature gradient was developed across the window by cooling one side of the window using gel-based ice packs.The other face of the window was heated by enabling power at different wattages through the window.The temperature of the inside and outside panes,current and voltage input,and temperature of the room and box were recorded.The data was used to calculate the apparent effective resistance of the window when not being heated vs.when being heated.The study concluded that,when window temperature was maintained close to the room temperature,the heated double pane window is effective in reducing heat loss by as much as 50%as compared to a non-heated double pane window.When temperature of the window was much higher than the room temperature,the heat loss through the window increased beyond that of a non-heated window.The issues encountered during the current stages of experiments are noted,and recommendations are provided for future studies.