HFO1234yf is a promising alternative for automobile air conditioners because of its low GWP of 4 and thermophysical properties similar to those of R134a. However, its performance is inferior to R410A. This makes it difficult to be applied to residential air-conditioners. A mixture of HFO1234yf and R32 is expected to balance both the GWP and COP requirement when applied to residential air-condit...

the aim of this study was to investigate the rate of water vapor permeability (wvp) and moisture sorption of starch-montmorillonite (mmt) nanocomposite films. the nanocomposite films were prepared using the casting method andglycerol was used as a plasticizer. the effect of glycerol concentration on wvp of the films was determined at 25°c with a relative humidity of 0-99% (inside and outside of...

the effects and influences of various parameters upon the efficiency and the overall volumetric mass transfer coefficients are important subjects to be studied in most liquid-liquid extraction processes. one of these important parameters is surface active agent (surfactant). in this paper, in order to study the effect of sodium dodecyl sulfate (sds) concentration on the efficiency and the avera...

this paper presents a numerical study of local mass transfer coefficients in a 90° bend using the rng version of k–e model to include the influence of curvature on the turbulent transport. simulations were performed for flow through a 90°, 3-d bend for reynolds numbers of 13500, 90000, and 390000, schmidt numbers of 2.53 and 700 and curvature ratios of 1.5, 2, and 2.5. the differences between t...

This paper numerically investigates the effect of mass transfer processes on spherical single bubble dynamics using the Hertz-Langmuir-Knudsen approximation for the mass flux across the interface. Bubble behavior, with and without mass transfer, is studied for different values of pressure wave amplitude and frequency, as well as initial bubble radius. Whereas mass transfer processes do not seem...

We show that the flux distribution of a wind from a cool star differs considerably from what is predicted by the theory for mass loss from hot stars. The differences are caused by the facts that 1) themass loss rates are lower, resulting in smaller optical depths in the wind, and 2) for winds from cool stars the temperature of thewind is higher than the temperature of the star while for winds f...

Dropwise condensation of humid air over hydrophilic and hydrophobic surfaces is numerically investigated using a phenomenological, Lagrangian model. Mass flux through droplets free surface predicted via vapor-diffusion Validation with literature experimental data successfully conducted at different humidities velocities. The accuracy the implemented model compared standard analogy between conve...

The main objective of this paper is to examine the effect of nanomaterials on mass transfer coefficient in bubble type absorption of carbon dioxide by experiment. The absorption process is carried out in a bubble column and in room temperature. Mass transfer coefficient, saturated concentration of CO2, and gas holdup are determined in this system. The kinds of nanomaterials, the concentrations ...

The present paper is an experimental investigation of roughness effects on nucleate pool boiling of refrigerant R113 on horizontal circular copper surfaces. The copper samples were treated by different sand paper grit sizes to achieve different surface roughness. The average surface roughness of the four samples was 0.901, 0.735, 0.65, and 0.09, respectively. The experiments were performed in t...