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Ernst‐Ulrich Schlünder

Bio: Ernst‐Ulrich Schlünder is an academic researcher from Karlsruhe Institute of Technology. The author has contributed to research in topics: Mass transfer & Diffusion. The author has an hindex of 23, co-authored 108 publications receiving 2040 citations.


Papers
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01 Jan 1993
TL;DR: In this paper, the transfert de chaleur and echangeurs de : chalesur were exchanged for conductivite and evaporation of condensation in the presence of radiation.
Abstract: Keywords: transfert de chaleur ; echangeurs de : chaleur ; materiaux ; conductivite ; evaporation ; condensation ; radiation ; pression Reference Record created on 2005-11-18, modified on 2016-08-08

387 citations

Journal ArticleDOI
TL;DR: In this article, it was shown that under certain conditions partially wetted surfaces yield practically the same drying rate as entirely wetted ones, and that less than 1% of the surface needed to be activated in order to give the same reaction rate such as an entirely activated one.

138 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a laboratory scale apparatus in which a single freely suspended particle can be coated under well defined and constant coating and drying conditions, and the particle growth rate and the development of particle morphology were measured and investigated under various experimental conditions.
Abstract: The coating and granulation of solid particles in a fluidized bed is a process which converts pumpable and atomizable liquids (solutions, slurries, melts) into granular solids in one step by means of drying. The solution to be processed is sprayed onto a fluidized bed. Particle growth can take place either via surface layering or agglomeration. In the case of surface layering the atomized droplets deposit a thin layer of liquid onto the seed particles. The solvent is then evaporated by the hot fluidizing, leaving behind the dissolved material on the surface. Although fluidized bed spray granulation and film coating have been applied in industry for several years, there is still a lack of understanding of the physical fundamentals and the mechanisms by which spherical granules are formed. Hence a new method was developed which allows the direct observation of the subsequent particle-forming mechanisms such as droplet deposition, spreading, wetting and drying. The authors present a laboratory scale apparatus in which a single freely suspended particle can be coated under well defined and constant coating and drying conditions. With this device, particle-growth-rate and the development of particle morphology were measured and investigated under various experimental conditions.

137 citations

Book ChapterDOI
TL;DR: In this paper, the actual contact time of the material at the hot surface is known, and the mixing number Nmix is necessary in order to predict drying rates for bench scale as well as for industrial dryers.
Abstract: In vacuum contact drying of particulate material heat is supplied from a hot surface to adjacent layers of mechanically agitated material. The drying rate curves can be predicted from physical properties alone provided that the actual contact time of the material at the hot surface is known. For mechanically agitated particulate material the actual contact time has been correlated to the time scale of the agitator by the “penetration model”. Only one empirical parameter, the so called mixing number Nmix is necessary in order to predict drying rates for bench scale as well as for industrial dryers.

117 citations

Journal ArticleDOI
TL;DR: In this article, the mixing number was found to lie between 2 and 25, depending on the design of the stirrer, which is a parameter introduced to describe the random particle motion.
Abstract: The heat transfer between packed and stirred beds and immersed surfaces is controlled by the contact resistance at the surface followed by the heat penetration resistance of the bulk. Both resistances can be predicted from model equations with sufficient accuracy. The contact resistance and the bulk penetration resistance for packed beds follow from physical properties, while the prediction of the bulk penetration resistance for stirred beds requires the introduction of an empirical parameter, the so-called mixing number in order to describe the random particle motion. The mixing number was found to lie between 2 and 25, depending on the design of the stirrer.

111 citations


Cited by
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Book
01 Jan 1971
TL;DR: In this paper, Ozaki et al. describe the dynamics of adsorption and Oxidation of organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water.
Abstract: 1: Magnetic Particles: Preparation, Properties and Applications: M. Ozaki. 2: Maghemite (gamma-Fe2O3): A Versatile Magnetic Colloidal Material C.J. Serna, M.P. Morales. 3: Dynamics of Adsorption and Oxidation of Organic Molecules on Illuminated Titanium Dioxide Particles Immersed in Water M.A. Blesa, R.J. Candal, S.A. Bilmes. 4: Colloidal Aggregation in Two-Dimensions A. Moncho-Jorda, F. Martinez-Lopez, M.A. Cabrerizo-Vilchez, R. Hidalgo Alvarez, M. Quesada-PMerez. 5: Kinetics of Particle and Protein Adsorption Z. Adamczyk.

1,870 citations

Journal ArticleDOI
TL;DR: In this paper, the limitations of the Fick's law for describing diffusion are discussed and it is argued that the Maxwell-Stefan formulation provides the most general and convenient approach for describing mass transport which takes proper account of thermodynamic non-idealities and influence of external force fields.

1,323 citations

Journal ArticleDOI
TL;DR: In this paper, a flow pattern/flow structure based heat transfer model for condensation inside horizontal, plain tubes is proposed based on simplified flow structures of the flow regimes, and also includes the effect of liquid-vapor interfacial roughness on heat transfer.

474 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the existing variance of second generation bioethanol production methodologies, namely pre-treatment, hydrolysis, fermentation and distillation, as well as the worth of second-generation production for future reference.
Abstract: It is a popular fact that the world's dependency on fossil fuel has caused unfavourable effects, including lessening crude oil reserve, decreasing air quality, rising global temperature, unpredictable weather change, and so on. As the effort to promote sustainability and independency from fossil fuel, bioethanol is now favoured as the blend or fossil petrol substitute. However, the feedstock functionality of first generation bioethanol production is restricted due to its edibleness since it would clash the feeding purpose. Second generation bioethanol production fulfils the impractical gap of first generation since it employs non-edible feedstock sourced from agriculture and forestry wastes. Lignocellulosic and starchy materials in them are convertible to fermentable sugars that are able to be further processed, resulting anhydrous bioethanol as the end product. This paper critically reviews the existing variance of second generation bioethanol production methodologies, namely pre-treatment, hydrolysis, fermentation and distillation, as well as the worth of second generation production for future reference. The discussions in this paper are also fit as the fundamental for feasible planning of second generation bioethanol production plant.

470 citations

Journal ArticleDOI
TL;DR: In this paper, the authors summarized and reviewed a great deal of information from the literature on dispersion in packed beds, and provided empirical correlations for the prediction of the dispersion coefficients (D T and D L) over the entire range of practical values of Sc and Pem.
Abstract: The phenomenon of dispersion (transverse and longitudinal) in packed beds is summarized and reviewed for a great deal of information from the literature. Dispersion plays an important part, for example, in contaminant transport in ground water flows, in miscible displacement of oil and gas and in reactant and product transport in packed bed reactors. There are several variables that must be considered, in the analysis of dispersion in packed beds, like the length of the packed column, viscosity and density of the fluid, ratio of column diameter to particle diameter, ratio of column length to particle diameter, particle size distribution, particle shape, effect of fluid velocity and effect of temperature (or Schmidt number). Empirical correlations are presented for the prediction of the dispersion coefficients (D T and D L) over the entire range of practical values of Sc and Pem, and works on transverse and longitudinal dispersion of non-Newtonian fluids in packed beds are also considered.

436 citations