This paper describes a properties-optimization work for the working fluids in NH3 / ionic liquid (ILs) based singleeffect absorption heat pumps. The optimum parameters of the IL can be used as criteria in screening task-specified ILs, which play the role of absorbents, in absorption heat pumps. First, a 8-parameter thermodynamic model to calculate performances of a single-effect absorption heat...

Test-area deformations are used to analyze vapor-liquid interfaces of Lennard-Jones particles by molecular dynamics simulation. For planar vapor-liquid interfaces the change in free energy is captured by the average of the corresponding change in energy, the leading-order contribution. This is consistent with the commonly used mechanical (pressure-tensor) route for the surface tension. By contr...

This work applies the molecular dynamics simulation method to study a Lennard-Jones liquid thin film suspended in the vapor and to explore the film thickness effect on its stability. For the accurate estimation of local pressure distributions in the film, an improved method is proposed and used. Simulation results indicate that profiles of the local surface tension distribution vary widely with...

Predictions of the transport properties self-diffusion coefficient and shear viscosity are presented for a recently developed molecular ammonia model. These data show mean unsigned deviations to the experiment over a temperature range from 200 to 500 K of 8 % for the self-diffusion coefficient and 12% for the shear viscosity. Furthermore, the vapor-liquid equilibria of the ternary system carbon...

An apparatus has been designed and constructed for the measurement of vapor-liquid equilibrium properties. The main components of the apparatus consist of an equilibrium cell and a vapor circulation pump. The cell and all of the system valves are housed inside a temperature controlled, insulated aluminum block. The temperature range of the apparatus is 260 K to 380 K to pressures of 6 MPa. The ...

Accurate molecular dynamics simulations are reported which quantify the contributions of two- and three-body interactions in the gas, liquid, and solid phases of argon at both subcritical and supercritical conditions. The calculations use an accurate two-body potential in addition to contributions from three-body dispersion interactions from third-order triple-dipole interactions. The number de...

The limits of superheat of some binary normal paraffin mixtures were measured at pressures up to. 2128 kPa using the floating droplet method. The variation of nucleation temperature with liquid phase mole fraction was found to be nearly linear for these n-paraffin solutions over the whole pressure range in which the experiments were performed. Homogeneous nucleation theory was used to predict t...

Numerical simulation of the vaporization of multi-component liquid fuels under high-pressure conditions is conducted in this study. A high-pressure drop vaporization model is developed by considering the high-pressure phase equilibrium which equates the fugacity of each component in both liquid and vapor phases. Peng-Robinson equation of state is used for the calculation of fugacity. To model t...

Surface tensions for liquid-vapor (lv), solid-liquid (sl), and solid-vapor (sv) interfaces are calculated from molecular dynamics simulations of the NaCl-water-air system. Three distinct calculation techniques based on thermodynamic properties are used to describe the multicomponent mixtures. Simulations of each bulk phase (including a liquid saturated solution) and various interfaces are carri...