Fluid turbulence simulations of divertor heat load for ITER hybrid scenario using BOUT++

2021 ◽  
Author(s):  
Xueyun Wang ◽  
Xueqiao Xu ◽  
Philip B Snyder ◽  
Zeyu Li
Keyword(s):  
Heat Flux ◽  
Steady State ◽  
Energy Loss ◽  
Heat Load ◽  
Type I ◽  
Fluid Turbulence ◽  
Drift Model ◽  
Steady State Operation ◽  
Different Types ◽  
The One

Abstract The BOUT++ six-field turbulence code is used to simulate the ITER 11.5MA hybrid scenario and a brief comparison is made among ITER baseline, hybrid and steady-state operation (SSO) scenarios. Peeling-ballooning instabilities with different toroidal mode numbers dominate in different scenarios and consequently yield different types of ELMs. The energy loss fractions (ΔWped/Wped) caused by unmitigated ELMs in the baseline and hybrid scenarios are large (~2%) while the one in the SSO scenario is dramatically smaller (~1%), which are consistent with the features of type-I ELMs and grassy ELMs respectively. The intra ELM divertor heat flux width in the three scenarios given by the simulations is larger than the estimations for inter ELM phase based on Goldston’s heuristic drift model. The toroidal gap edge melting limit of tungsten monoblocks of divertor targets imposes constraints on ELM energy loss, giving that the ELM energy loss fraction should be smaller than 0.4%, 1.0%, and 1.2% for ITER baseline, hybrid and SSO scenarios, correspondingly. The simulation shows that only the SSO scenario with grassy ELMs may satisfy the constraint.

scholarly journals Non-steady-state heat conduction in composite walls

2014 ◽  
Vol 470 (2165) ◽  
pp. 20130605 ◽  
Author(s):  
Bernard Deconinck ◽  
Beatrice Pelloni ◽  
Natalie E. Sheils
Keyword(s):  
Heat Flux ◽  
Heat Conduction ◽  
Steady State ◽  
Composite Materials ◽  
Solution Method ◽  
One Dimensional ◽  
Infinite Domains ◽  
Steady State Heat ◽  
The One ◽  
Composite Walls

The problem of heat conduction in one-dimensional piecewise homogeneous composite materials is examined by providing an explicit solution of the one-dimensional heat equation in each domain. The location of the interfaces is known, but neither temperature nor heat flux is prescribed there. Instead, the physical assumptions of their continuity at the interfaces are the only conditions imposed. The problem of two semi-infinite domains and that of two finite-sized domains are examined in detail. We indicate also how to extend the solution method to the setting of one finite-sized domain surrounded on both sides by semi-infinite domains, and on that of three finite-sized domains.

scholarly journals Thermal comfort in reduced models of broilers' houses, under different types of roofing materials

2013 ◽  
Vol 33 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Eduardo A. de Almeida ◽  
Roberta Passini
Keyword(s):  
Thermal Comfort ◽  
Heat Load ◽  
The State ◽  
State University ◽  
Asbestos Cement ◽  
Different Types ◽  
Humidity Index ◽  
The One ◽  
Roofing Materials ◽  
Vegetable Fiber

The research was developed to evaluate the use of different types of roofing materials regularly used in poultry houses. Measurements of thermal comfort were made through the use of techniques such as the Black Globe and Humidity Index (BGHI), the Thermal Heat Load (THL) and Enthalpy (H). Conducted in the State University of Goiás, during the months of April and May, 2011, the experiment was composed of five different treatments: AC - Asbestos cement tiles, BA -Bamboo tiles, BAP - Bamboo tiles painted in white, FB -Vegetable fiber tiles and bitumen, FBP -Vegetable fiber tiles and bitumen painted in white. The experiment consisted in 15 repetitions, which were considered the different days of measurements taken. Throughout the studied period, the time of the day considered the least comfortable was the one observed at 2:00pm, and the coverage of vegetable fiber and bitumen showed the highest value of BGHI (84.1) when compared to other types of coverage, characterizing a situation of lower thermal comfort, and no difference was found for THL and H on treatments in the studied region.

Electrophysiological characterization of different types of neurons recorded in vivo in the motor cortex of the cat. II. Membrane parameters, action potentials, current-induced voltage responses and electrotonic structures

1993 ◽  
Vol 69 (6) ◽  
pp. 1865-1879 ◽  
Author(s):  
A. Baranyi ◽  
M. B. Szente ◽  
C. D. Woody
Keyword(s):  
Steady State ◽  
Membrane Potential ◽  
Motor Cortex ◽  
Action Potential ◽  
Action Potentials ◽  
Cell Types ◽  
Type I ◽  
Firing Threshold ◽  
Current Pulses ◽  
Different Types

1. Electrical properties of four functional classes [inactivating bursting (ib), noninactivating bursting (nib), fast spiking (fsp), and regular spiking (rsp)] of neurons in the motor cortex of conscious cats were studied with the use of intracellular voltage recording and single-electrode voltage-clamp (SEVC) techniques. Evaluations were made of action potentials and afterpotentials, current-voltage (I-V) relationships, and passive cable properties. Values of membrane potential (Vm), input resistance (RN), membrane time constant (T0), and firing threshold (T50) were also measured. The data were used to extend the electrophysiological classifications of neurons described in the companion paper. 2. Average values of Vm (from -63 to -66 mV), action-potential amplitudes (from 72 to 77 mV), and firing threshold (-54 mV) were not statistically different in different types of neurons. However, the magnitude of intracellularly injected depolarizing current required to induce spike discharge at 50% probability varied significantly (from 0.6 to 1.1 nA) among cell types. The mean RN and T0 measured at Vm varied between 8.3 and 19.8 M omega, and 7.2 and 15.1 ms, respectively, in the cell classes. 3. Action potentials were overshooting. Their mean duration at half amplitude varied from 0.25 to 0.73 ms among different cell types. Three types of action-potential configurations were distinguished. Type I action potentials found in nib and rsp neurons were relatively fast and had a depolarizing afterpotential (DAP) as well as fast and slow after hyperpolarizations (fAHPs, sAHPs). Type II action potentials found in ib and rsp cells had relatively slow rise and decay phases, DAPs, and sAHPs. Their fAHPs were small or absent. Type III action potentials were found exclusively in fsp cells, had very short durations, prominent fAHPs, but no sAHPs. 4. Steady-state I-V relationships were determined by measuring voltage responses to 0.2- to 1.0-nA hyperpolarizing, rectangular current pulses at different membrane potentials. Both RN and T0 exhibited nonlinear behavior over wide ranges of membrane potential; however, between -65 and -75 mV, the I-V relationships varied little, and they appeared constant in most cells. The steady-state values of RN increased with decreasing, and decreased with increasing the membrane potential in all but fsp cells. The I-V relationships were virtually linear in fsp neurons. 5. Transient I-V relationships were studied by measuring voltage responses to depolarizing and hyperpolarizing, rectangular current pulses of increasing amplitude from a preset membrane potential of -70 mV.(ABSTRACT TRUNCATED AT 400 WORDS)

Heat-Flux Measurements and Predictions for the Blade Tip Region of a High-Pressure Turbine

2006 ◽  
Author(s):  
S. M. Molter ◽  
M. G. Dunn ◽  
C. W. Haldeman ◽  
R. F. Bergholz ◽  
P. Vitt
Keyword(s):  
Heat Flux ◽  
High Pressure ◽  
Steady State ◽  
Flow Field ◽  
Turbine Blade ◽  
Heat Load ◽  
Complex Flow ◽  
High Pressure Turbine ◽  
Blade Tip ◽  
Blade Tips

High-pressure turbine blade tips operate in a highly complex flow environment that makes designing new blades for increased life difficult. Computational fluid dynamics simulations of the tip flow field may be able to guide new designs to improve the blade life, but the analysis techniques need to be verified against detailed measurements before they can be applied. The current paper presents measurements of heat flux and pressure in the blade tip region of a modern one-and-one-half stage high-pressure turbine operating at design corrected conditions in a rotating rig. Both flat tip and recessed, or squealer, tip blades were used in the experiments. The measurements indicate that the recessed tip, used in the majority of modern turbines to minimize blade damage from rubs, increases the blade heat load overall, and creates several hot spots on the floor of the recess for an uncooled airfoil. The tip data also showed there were significant unsteady variations in the heat load at the vane passing frequency. Steady state CFD calculations were completed for both flat and squealer tip configurations to examine if the analysis could capture the details that were measured. The CFD, while not capable of estimating the unsteady heat load component and generally over predicting the overall heat flux by 10–25%, did capture the measured heat flux trends in the recessed tip. These results show that steady-state CFD analysis can be useful in predicting the complex flow field and heat load distribution in turbine blade tips to help guide future blade designs.

Experimental Heat Flux Analysis of an Automotive Diesel Engine in Steady-State Operation and During Warm-Up

2011 ◽  
Author(s):  
Christian Donn ◽  
Wolfgang Zulehner ◽  
Daniel Ghebru ◽  
Ulrich Spicher ◽  
Matthias Honzen
Keyword(s):  
Heat Flux ◽  
Steady State ◽  
Diesel Engine ◽  
Flux Analysis ◽  
Warm Up ◽  
Experimental Heat ◽  
Steady State Operation

Methionine-Specific Staining of Collagen

1982 ◽  
Vol 40 ◽  
pp. 294-295
Author(s):  
E.M. Kuhn ◽  
K.D. Marenus ◽  
M. Beer
Keyword(s):  
Amino Acids ◽  
Collagen Fibers ◽  
Type Iii Collagen ◽  
Type I ◽  
Electron Microscopic ◽  
Good Correspondence ◽  
Specific Staining ◽  
Type Iii ◽  
Different Types ◽  
Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

The concept of motivation for effective credit risk management

2020 ◽  
Vol 26 (11) ◽  
pp. 2567-2593
Author(s):  
M.V. Pomazanov
Keyword(s):  
Risk Management ◽  
Economic Modeling ◽  
Type I ◽  
Credit Risk Management ◽  
Curve Modeling ◽  
Business Functions ◽  
The Common ◽  
Lending Decisions ◽  
The One

Subject. The study addresses the improvement of risk management efficiency and the quality of lending decisions made by banks. Objectives. The aim is to present the bank management with a fair algorithm for risk management motivation on the one hand, and the credit management (business) on the other hand. Within the framework of the common goal to maximize risk-adjusted income from loans, this algorithm will provide guidelines for ‘risk management’ and ‘business’ functions on how to improve individual and overall efficiency. Methods. The study employs the discriminant analysis, type I and II errors, Lorentz curve modeling, statistical analysis, economic modeling. Results. The paper offers a mechanism for assessing the quality of risk management decisions as opposed to (or in support of) decisions of the lending business when approving transactions. The mechanism rests on the approach of stating type I and II errors and the corresponding classical metric of the Gini coefficient. On the ‘business’ side, the mechanism monitors the improvement or deterioration of the indicator of changes in losses in comparison with the market average. Conclusions. The study substantiates the stimulating ‘rules of the game’ between the ‘business’ and ‘risk management’ to improve the efficiency of the entire business, to optimize interactions within the framework of internal competition. It presents mathematical tools to calculate corresponding indicators of the efficiency of internally competing entities.

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