In designing of condensers, the prediction of pressure drop is as important as the prediction of heat transfer coefficient. Modeling of two phase flow, particularly liquid – vapor flow under diabatic conditions inside a horizontal tube using CFD analysis is difficult with the available two phase models in FLUENT due to continuously changing flow patterns. In the present analysis, CFD analysis o...

In the vapor phase a solvent-free spectroscopic analysis of dye molecules is applicable [1-3]. For some dye vapors laser action was achieved [1-3]. The dye vapor pressure rises approximately exponentially with temperature. Reasonable vapor pressures (p around 100 Pa = 1 mbar) are obtained for many non-ionic dyes in a temperature region between 200 and 400 °C without considerable thermal decompo...

HYPOTHESIS Droplet wettability and mobility play an important role in dropwise condensation heat transfer. Heat exchangers and heat pipes operate at liquid-vapor saturation. We hypothesize that the wetting behavior of liquid water on microstructures surrounded by pure water vapor differs from that for water droplets in air. EXPERIMENTS The static and dynamic contact angles and contact angle h...

Vapor pressures in the range of 256 to 331 K and saturated liquid and vapor densities from 315 to 331 K have been measured for difluoromethane (HFC-32) on the saturation line by means of variable volume and static experimental methods. Our results have been combined with literature values, and on the basis of all the measurements, accurate analytical correlations for saturated liquid and vapor ...

A precise experimental method for studying binary vapor-liquid equilibrium is to measure total pressure (P) as a function of the mole fraction in the liquid phase (2). The mole fraction in the vapor (y) is calculated from imthermal P-x experimental data using the Gibbs-Duhem equation. A similar procedure for adsorption is to measure total mass (m) of gas adsorbed as a function of the mole fract...

A new dual-fluid concept was studied that could eventually find application for cold-gas propulsion for small space satellites or other constant flow applications. In basic form, the concept uses two different refrigerant working fluids, each having a different saturation vapor pressure. The higher vapor pressure refrigerant remains in the saturation phase and is used to pressurize the lower sa...

The generalized Replica Exchange Method (gREM) is extended into the isobaric-isothermal ensemble, and applied to simulate a vapor-liquid phase transition in Lennard-Jones fluids. Merging an optimally designed generalized ensemble sampling with replica exchange, gREM is particularly well suited for the effective simulation of first-order phase transitions characterized by "backbending" in the st...

Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of ...