ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Articles  (13)
  • Articles: DFG German National Licenses  (13)
  • heat transfer  (13)
  • 2010-2014
  • 1990-1994  (5)
  • 1985-1989  (5)
  • 1980-1984  (3)
  • 1950-1954
  • Technology  (13)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Plasma chemistry and plasma processing 13 (1993), S. 633-653 
    ISSN: 1572-8986
    Keywords: Rarefied plasma ; spherical particle ; particle charging ; Debye screening ; heat transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The methods of the kinetic theory tire applied for the description of charge and heat transfer front a rarefied plasma to a spherical particle for an arbitrary ratio between Dehye length and particle radius. Different models of the velocity distribution functions of the charged plasma species are considered. The results of the numerical analysis show that the intensity of plasma-particle heat exchange is greatly influenced by gas ionization, participation of electrons and ions in the transfer processes, particle charging, and .screening properties of the plasma. Even at a low degree of ionization, the electron and ion contribution to the heat transfer remains significant.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Plasma chemistry and plasma processing 12 (1992), S. 383-402 
    ISSN: 1572-8986
    Keywords: Rarefied plasma flow ; nonspherical metallic or nonmetallic particle ; particle charging ; heat transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The interaction of a nonspherical metallic or nonmetallic particle with a rarefied thermal plasma flow is considered. Heat transfer to a particle of arbitrary shape with an extremely thin plasma sheath due to, respectively, gas molecules, electrons, and ions is described. Analytical expressions are derived for charge and heat fluxes in the particular case of a spheroidal metallic or nonmetallic particle in a subsonic plasma flow. It has been shown that the intensity of heat exchange is greatly influenced by gas ionization, charge transfer processes, and particle shape, velocity, and orientation in the plasma flow.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Transport in porous media 6 (1991), S. 183-194 
    ISSN: 1573-1634
    Keywords: Free convection ; heat transfer ; porous media ; natural convection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract The effects of anisotropy on the steady laminar boundary-layer free convection over a vertical impermeable surface are analysed by using the method of integral relations. If the permeability in the direction orthogonal to the plate is greater than the permeability along the plate, then there is an increase in the temperature field.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Plasma chemistry and plasma processing 10 (1990), S. 71-85 
    ISSN: 1572-8986
    Keywords: Thermal plasmas ; spouted bed ; hydrodynamics ; heat transfer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The literature reveals very little intformation about plasma spouted bed hydrodynamics. Spouting of corindon particles with diameters ranging from 0.4 to 3.36 mm with argon plasma was conducted in a 90-mm-diameter column in the temperature range 300–1300°C. It was found that the maximum spoutable height (Hm) decreases with increasing particle diameter and decreasing mean bed temperature. A relation between the inlet plasma velocity and Hm is proposed. Concerning heat transport phenomena in the annulus, measurements and calculations indicate a large axial diffusivity but a poor radial mixing. Typical values of Dz and Dr are proposed on the basis of an identification procedure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Transport in porous media 5 (1990), S. 299-323 
    ISSN: 1573-1634
    Keywords: Supercritical convection ; heat transfer ; numerical simulation ; porous media ; geothermal systems ; water ; critical point
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Fluid and heat flow at temperatures approaching or exceeding that at the critical point (374 °C for pure water, higher for saline fluids) may be encountered in deep zones of geothermal systems and above cooling intrusives. In the vicinity of the critical point the density and internal energy of fluids show very strong variations for small temperature and pressure changes. This suggests that convective heat transfer from thermal buoyancy flow would be strongly enhanced at near-critical conditions. This has been confirmed in laboratory experiments. We have developed special numerical techniques for modeling porous flow at near-critical conditions, which can handle the extreme nonlinearities in water properties near the critical point. Our numerical simulations show strong enhancements of convective heat transfer at near-critical conditions; however, the heat transfer rates obtained in the simulations are considerably smaller than data reported from laboratory experiments by Dunn and Hardee. We discuss possible reasons for this discrepancy and develop suggestions for additional laboratory experiments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Plasma chemistry and plasma processing 9 (1989), S. 135S 
    ISSN: 1572-8986
    Keywords: Modeling ; thermal plasma processing ; supersonic jets ; heat transfer ; control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract Thermal plasma processing of materials is a rapidly growing area of research. The commercialization of these processes, however, has been limited by the lack of fundamental understanding of how the various processes work. Research has historically focused on developing models of fluid flow and heat transfer to particles injected into either DC arc or RF plasma jets. These models in the past have simplified boundary conditions to meet computational limitations. Recent advances in models have now been made, allowing evaluations of more of the plasma process variables. Supersonic flow modeling in a DC jet and modeling of the effects of particle loading (particulate feed rate) have been accomplished and are reviewed here. Materials processing using thermal plasmas has been separated into the categories of synthesis, melting, and deposition, and is discussed in view of the processing effects on the resultant material structures. Process modeling leading to process understanding is reviewed with an emphasis on process control and optimization. Commercialization of plasma processes requires controls and process transducers which result from experimentation and process models. Approaches to develop process controls from the current technical base are presented.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Transport in porous media 3 (1988), S. 95-106 
    ISSN: 1573-1634
    Keywords: Free convection ; heat transfer ; Porous media ; natural convection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract An analysis is presented for the calculation of heat transfer due to free convective flow along a vertical plate embedded in a porous medium with an arbitrarily varying surface heat flux. By applying the appropriate coordinate transformations and the Merk series, the governing energy equation is expressed as a set of ordinary differential equations. Numerical solutions are presented for these equations which represent universal functions and several computational examples are provided.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Transport in porous media 3 (1988), S. 325-341 
    ISSN: 1573-1634
    Keywords: Natural convection ; heat transfer ; boundaries ; modes ; critical ; Nusselt ; power integral method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract The ‘power integral method’ of calculating heat transfer across a convecting porous layer is extended to flux and porous boundaries. Convection starts at lower Rayleigh numbers for constant flux than for isothermal impervious boundaries and the flux is much greater. At higher Rayleigh numbers, as more of the higher modes contribute to the flux, the type of boundary has less influence on the heat transfer across the layer. For constant flux boundaries, simplified equations are developed to determine critical values for the second and higher modes and these values can be related simply to those for isothermal impervious boundaries.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Transport in porous media 3 (1988), S. 437-453 
    ISSN: 1573-1634
    Keywords: Natural convection ; heat transfer ; flow ; critical ; Nusselt ; power integral method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Temperature decay in sealed rockbeds has been recorded. The rockbeds lost energy through the top surface and the results indicated that different natural convective flows occurred in beds of fixed depth and rock size but different lateral dimensions. However, the different flows had no effect on the mean power density dissipated through the top of the beds. A simple numerical conduction model based on the ‘power integral method’ was used to calculate the temperature decay. The experimental results suggested that an insulated porous lower boundary was appropriate for the model and this gave the best agreement with the experiments.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Transport in porous media 1 (1986), S. 361-370 
    ISSN: 1573-1634
    Keywords: Vertical layers ; mathematical models ; geothermal systems ; heat transfer ; convection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Technology
    Notes: Abstract Some studies already made have investigated the criterion for onset of convection and heat and mass flow distributions in a porous slab composed of horizontal layers of different materials. This paper reports a study of such criteria for the case where the slab is composed of vertically-aligned strata with different permeabilities and thermal conductivities. This has particular relevance to where blocks of different materials abut in a vertical plane, as well as the case of very narrow highly permeable vertical layers which represent vertical faults in a geological structure. Results indicate that permeability and/or thermal conductivity contrasts between layers can significantly affect the flow pattern and the spatial distribution of the surface heat flux. The concentration of flow in highly permeable ‘faults’ produces marked irregularities in the heat flow through the surface above them.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Plasma chemistry and plasma processing 3 (1983), S. 97-113 
    ISSN: 1572-8986
    Keywords: Knudsen effect ; heat transfer ; small particles ; thermal plasmas ; analytical studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract The Knudsen effect on heat transfer to a particle exposed to a thermal plasma is important for many practical situations experienced in plasma chemistry and plasma processing. This paper provides theoretical results of this effect based on the “heat conduction potential jump” approach. It is shown that a correction factor which depends on the Knudsen number must be introduced into the expressions for heat fluxes obtained previously based on the continuum approach. The Knudsen effect is stronger for smaller particles and it is also more pronounced for an Ar-H2 plasma (compared to Ar and nitrogen plasmas at the same temperature). Since the Knudsen effect depends on the surface temperature of a particle, calculation of particle heating becomes more complicated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Plasma chemistry and plasma processing 3 (1983), S. 351-366 
    ISSN: 1572-8986
    Keywords: Small particles ; heat transfer ; drag ; Knudsen effect ; convection ; thermal plasma ; computation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract In this paper computational results are presented which reveal the effects of the Knudsen number on heat transfer and drag of small particles in a flowing thermal argon plasma. The Knudsen number is restricted to moderate values so that “temperature jump” and “velocity slip” conditions may be employed, and for the governing equations the continuum approach remains valid. It is shown that the ratio of the heat fluxes with and without the Knudsen effect is almost identical to the ratio obtained by the authors for the case of pure heat conduction. This fact is very important for modeling of the behavior of particles injected into an actual plasma reactor when the Knudsen effect has to be taken into account.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Plasma chemistry and plasma processing 2 (1982), S. 361-386 
    ISSN: 1572-8986
    Keywords: Transferred arc ; characteristics ; heat transfer ; experimental
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Technology
    Notes: Abstract A specially designed plasma chamber was constructed to study the operating characteristics of a dc plasma-transferred arc of argon, struck between a fluid convective cathode and a water-cooled anode. The arc voltage increased markedly with arc length and with an increase in the inlet velocity of the argon flow past the cathode tip, and much less with an increase in current. Radiation from the plasma column to the chamber walls and transfer of energy to the anode were the two principal modes of transfer of the arc energy. The former was dominant in the case of long arcs and at high inlet argon velocities. At the anode, the major contribution was from electron transfer, which occurred on a very small area of the anode (∼5 mm in diameter). Convective heat transfer from the plasma was somewhat less. In all cases, the arc energy contributions to cathode cooling and to the exit gas enthalpy were small. From total heat flux and radiative heat transfer measurements, it was estimated that the plasma temperature just above the anode was in the range 10,000–12,000 K. Preliminary experiments with an anode consisting of molten copper showed that the arc root was no longer fixed but moved around continuously. The arc was othwewise quite stable, and its operating characteristics differed little from those reported for solid anodes, in spite of the greater extent of metal vaporization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...