Showing papers by "Johann Fischer published in 2007"
TL;DR: In this article, a thermodynamic screening of 31 pure component working fluids for organic Rankine cycles (ORC) is given using BACKONE equation of state, the fluids are alkanes, fluorinated alkane, ethers and fluorinated ethers.
1,036 citations
TL;DR: In this article, the number of droplet molecules and their density, drift velocity, and temperature profiles as a function of time were analyzed for a pure Lennard-Jones fluid.
Abstract: Droplet evaporation by heat transfer is investigated by molecular dynamics simulations for a pure Lennard-Jones fluid. Two different initial conditions are treated: (1) a droplet surrounded by its vapor in equilibrium, (2) a cold droplet surrounded by warm vapor. In both cases heat is transferred from a heat bath. Results are the numbers of droplet molecules N d and density, drift velocity, and temperature profiles as functions of time. For the small droplets considered N d depends on the definition of a droplet molecule. The density profiles as function of time show a transition from a droplet with liquid–vapor interface to a cluster of interfacial type and finally to the gas state. The temperature at a given time is nearly constant within the droplets or clusters but strong gradients occur in the gas. In case of evaporation of a cold droplet surrounded by warm vapor we observed initially cooling down of the droplet corresponding to pressure jump evaporation and thereafter slower evaporation because of lower initial state vapor density.
23 citations
TL;DR: The present theory is used to study the structure of adsorbed layers, the excess adsorption isotherms, and the capacitance of the double layer in the statistical associating fluid theory.
Abstract: A simple density functional approach for modeling the adsorption of biomolecules is considered. The model comprises a three-component mixture consisting of spherical and differently charged ions and chain molecules. Spherical ions can form associative bonds with selected segments of a chain. To enable the formation of bonds between chain segments and spherical ions, the statistical associating fluid theory is applied. The present theory is used to study the structure of adsorbed layers, the excess adsorption isotherms, and the capacitance of the double layer.
14 citations
TL;DR: In this article, an extension of the mean force method is introduced, where the absolute value of the bulk density is determined by particle balance, and it is possible to calculate adsorption isotherms from the Henry regime to any finite concentration.
Abstract: The adsorption of solutes from a dilute liquid solution is of great technical importance but calculations of the local density of the solute and of the adsorption isotherm by standard molecular simulation yield large scattering with increasing dilution. As alternative the mean force (MF) method was suggested where the MF on a constrained solute molecule is integrated over a path from the bulk fluid to the wall. It has already been shown that the MF method gives reliable results for the relative local density, even at high dilution. Here, an extension of this method is introduced, where the absolute value of the bulk density is determined by particle balance. Thus, it is possible to calculate adsorption isotherms from the Henry regime to any finite concentration. Molecular dynamics simulations for the local density and the adsorption isotherm were performed for a model solution consisting of tetrahedral Lennard–Jones (LJ) solvent and linear LJ solute molecules in contact with a plane wall. It is found that...
6 citations