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Sharp Tischrechner »EL-R297«, schwarz
Bestseller
20,42 € *
zzgl. 4,95 € Versand

Tischrechner »EL-R297«, Eco-Concept Rechner, LC-Display: 12 Stellen, mit Steuerberechnung, Runden-Funktion, Simulation von Preis / Kosten / Marge und Gesamtsummenspeicher, Solar-/ Batteriebetrieb, Gewicht: 228

Anbieter: OTTO
Stand: 30.03.2020
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Modeling and simulation of complete liquid-vapo...
55,80 € *
ggf. zzgl. Versand

This work deals with modeling and numerical simulation of fluid flow and heat transfer associated with phase change process inside both isotropic and anisotropic porous media, based on the Two-Phase Mixture Model (TPMM) along with the assumption of Local Thermal Equilibrium (LTE) and Non-Equilibrium (LTNE) conditions. In particular, it demonstrates the necessity and usefulness of a newly proposed smoothing algorithm for handling the sharp discontinuities in the effective diffusion coefficient in order to avoid the occurrence of non-physical “jump” in the predicted temperature distribution during the numerical simulation of the complete phase change process inside porous media. For the purpose of demonstration, one- and two-dimensional phase change problems operated in the Darcy flow regime have been considered.The Finite Volume Method (FVM) has been used on both staggered and non-staggered grid layouts in order to solve the governing conservation equations. In this work, after critically analyzing the drawbacks of the existing enthalpy formulation based on TPMM, a modified formulation has been also developed that can easily accommodate substantial density variations in the single phase regions. The results obtained from the modified enthalpy formulation have been compared with that predicted by the existing modified volumetric enthalpy formulation and excellent agreements have been observed for all tested cases. A thorough parametric study, using both LTE and LTNE models, indicates that the adoption of the proposed smoothing algorithm successfully eliminates “jump” in the predicted temperature distribution and does not alter the overall energy and momentum balance. All tested cases, covering applicable ranges of parametric variations, could be physically interpreted. The methodology is, therefore, recommended for future simulations of complete phase change process inside porous media. The results also show that the modified enthalpy formulation requires significantly less computation time thanmodified volumetric enthalpy formulation.

Anbieter: Dodax
Stand: 30.03.2020
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Sharp Tischrechner »EL-330W«, weiß
Top-Produkt
13,21 € *
zzgl. 4,95 € Versand

Tischrechner »EL-330W«, angewinkeltes LC-Display: 10 Stellen, mit Steuerberechnung, Simulation von Preis / Kosten / Marge und Währungsumrechnung, Solar-/ Batteriebetrieb, Gewicht: 55 g

Anbieter: OTTO
Stand: 30.03.2020
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Contaminant transport in a fractured chalk aquifer
49,00 € *
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Transport processes in fractured aquifer are characterised by a couple of transport mechanisms within the fracture and the neighbouring matrix. To understand the possible transport mechanisms of tracers in a fractured chalk block, laboratory single- and multi-tracer tests were carried out in two blocks under defined boundary conditions. The breakthrough curves (BTC's) of the tracers are governed by sharp peaks due to advective transport and dispersive respectively diffusive transport processes in the tailing part of the BTC's. The simulation of the BTC's with the single fissure dispersion model could not reasonably fit the BTC's. A multichannel SFDM with the superposition of BTC's of at least two different flow paths, resulted in an acceptable fit (by calculating the cumulative tracer breakthrough and recovery curves). Those simulations indicate the existence of flow channelling effects within the fracture. The results showed that matrix diffusion process plays only a minor role in the determination of the fate of nitrate in the groundwater aquifers. The key factor controlling the fate of nitrate in the groundwater is the redox process.

Anbieter: Dodax
Stand: 30.03.2020
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Sharp Tischrechner »EL-330W«, weiß
Aktuell
13,21 € *
zzgl. 4,95 € Versand

Tischrechner »EL-330W«, angewinkeltes LC-Display: 10 Stellen, mit Steuerberechnung, Simulation von Preis / Kosten / Marge und Währungsumrechnung, Solar-/ Batteriebetrieb, Gewicht: 55 g

Anbieter: OTTO
Stand: 30.03.2020
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Shear-driven Film Separation
68,00 € *
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Dynamic thin liquid films driven by an adjacent gas flow have been subject to many investigations due to their presence in many engineering applications. More specifically though, the behavior of such films at a sharply expanding corner has received little attention, but can be observed in internal combustion engines, liquid atomizer systems, and refrigerant flows in evaporators. Efforts to validate computational models of the propagation and separation of films are limited by the lack of reliable non-intrusive techniques to measure and analyze dynamic film parameters. In this study, film propagation models and film separation models were validated separately using experimental measurements. For film thickness measurement, a laser focus displacement instrument was used following a theoretical and experimental qualification of the instrument. Thickness measurements with corresponding film velocities were then compared to the computational results of two numerical simulations. The experimental facility was also used to measure film separation at a sharp corner, and two film separation models were validated using these measurements.

Anbieter: Dodax
Stand: 30.03.2020
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Sharp Tischrechner »EL-R297«, schwarz
Empfehlung
20,42 € *
zzgl. 4,95 € Versand

Tischrechner »EL-R297«, Eco-Concept Rechner, LC-Display: 12 Stellen, mit Steuerberechnung, Runden-Funktion, Simulation von Preis / Kosten / Marge und Gesamtsummenspeicher, Solar-/ Batteriebetrieb, Gewicht: 228

Anbieter: OTTO
Stand: 30.03.2020
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ADAPTIVE FREE-KNOT SPLINES AND INFERENCE
49,00 € *
ggf. zzgl. Versand

In this book, we propose a function estimation procedure using adaptive free-knot splines (AFKS) and associated algorithm for implementation in nonparametric regression. Knot selection is extremely important for estimating a function with complicated structure by spline functions. The AFKS allows variable knot numbers and replacements of knots at any locations and multiple knots at the same location. This flexibility leads to an adaptive spline estimator that adapts to any function with inhomogeneous smoothness, including a sharp kink or discontinuity, which substantially improves the representation power of splines. A new knot selection scheme is proposed, by utilizing an adaptive model selection criterion (AMSC) and an Evolutionary Algorithm (EA). The AMSC guards against the selection error in searching through a large candidate knot space, while the EA enables us to search the global minima of AMSC. The performance of the AFKS is examined via simulations, which demonstrates its superiority over the existing spline methods and wavelet estimators. This book would be useful for researchers who analyze real and complex data structures.

Anbieter: Dodax
Stand: 30.03.2020
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Multi-component Effects of Biofuels and Blends
75,90 € *
ggf. zzgl. Versand

Petroleum-based fuels are used in IC engines for power generation. Global demand for petroleum-based fuels has been increasing in the past decade. Meanwhile, the increase in supply is growing at a slower rate, resulting in a sharp rise in energy cost. On the other hand, diesel engine is known to have better thermal efficiency than spark-ignition engine due to higher compression ratio. Three-dimensional multi-physics simulations were conducted to characterize biodiesel combustion in compression ignition engines, using various dual injection scheme. Simulations were conducted to test various injection schemes, fuel compositions and their effects on the engine out emissions with the main focus on simultaneous reductions in NOx and soot. A robust multi-component evaporation model for droplets is developed. The model allows accurate description of the evaporation process of fuel droplets while maintaining the computational efficiency. The analysis in this should benefit any researchers developing next generation, clean combustion technologies.

Anbieter: Dodax
Stand: 30.03.2020
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