Enhancing the cooling and dehumidification performance of indirect evaporative cooler by hydrophobic-coated primary air channels

2021 ◽  
Vol 179 ◽  
pp. 121733
Author(s):  
Yunran Min ◽  
Wenchao Shi ◽  
Boxu Shen ◽  
Yi Chen ◽  
Hongxing Yang
Keyword(s):  
Evaporative Cooler ◽  
Air Channels

Diagnostics Development for E-Beam-Excited Air Channels

1985 ◽  
Author(s):  
D. J. Eckstrom ◽  
M. N. Spencer ◽  
J. S. Dickinson
Keyword(s):  
Air Channels

A novel approach in numerical simulation of contaminant removal by air sparging

2007 ◽  
Vol 7 (3) ◽  
pp. 163-170
Author(s):  
N. Jacimovic ◽  
T. Hosoda ◽  
M. Ivetic ◽  
K. Kishida
Keyword(s):  
Mass Transfer ◽  
Deterministic Model ◽  
Water Phase ◽  
Air Sparging ◽  
Order Kinetic ◽  
Contaminant Removal ◽  
Water Compartments ◽  
Novel Approach ◽  
Adopted Model ◽  
Air Channels

The paper presents a mechanistic/deterministic model for simulation of mass removal during air sparging. From the point of numerical modeling, there are two issues considering air sparging: modeling of air flow and distribution and modeling of mass transport and transfer. Several processes, which are commonly neglected, such as air channeling and pollutant advection by the water phase, are taken into account. The numerical model presented in this paper considers all relevant for mass transfer during the air sparging. Model includes hydrodynamics of air and water phase; calculated air volume content is divided into a number of air channels surrounded by the water phase, which is divided into two compartments. First compartment is immobile and it is in contact with air phase, while the second compartment is mobile. This “mobile-immobile” formulation is a common approach for description of solute transport by groundwater. Mass transfer between two water compartments is modeled as a first order kinetic, where the mass transfer coefficient, representing diffusion and advection in the water phase towards the air channels, is parameter needed to be calibrated. Sorption for both water compartments is considered. The adopted model of contaminant evaporation at the air-water interface is verified by comparison with experimental results available from published sources. Model is used for simulation of two-dimensional air sparging laboratory experiment. Good overall agreement is observed. It is showed that the efficiency of air sparging can be influenced by natural groundwater flow.

scholarly journals Design of Thermal Insulation Materials with Different Geometries of Channels

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2217
Author(s):  
Daniela Șova ◽  
Mariana Domnica Stanciu ◽  
Sergiu Valeriu Georgescu
Keyword(s):  
Thermal Conductivity ◽  
Porous Structure ◽  
Base Material ◽  
Cost Effective ◽  
Heat Radiation ◽  
Average Temperature ◽  
Temperature Regimes ◽  
The Face ◽  
Inclined Channels ◽  
Air Channels

Investigating the large number of various materials now available, some materials scientists promoted a method of combining existing materials with geometric features. By studying natural materials, the performance of simple constituent materials is improved by manipulating their internal geometry; as such, any base material can be used by performing millimeter-scale air channels. The porous structure obtained utilizes the low thermal conductivity of the gas in the pores. At the same time, heat radiation and gas convection is hindered by the solid structure. The solution that was proposed in this research for obtaining a material with porous structure consisted in perforating extruded polystyrene (XPS) panels, as base material. Perforation was performed horizontally and at an angle of 45 degrees related to the face panel. The method is simple and cost-effective. Perforated and simple XPS panels were subjected to three different temperature regimes in order to measure the thermal conductivity. There was an increase in thermal conductivity with the increase in average temperature in all studied cases. The presence of air channels reduced the thermal conductivity of the perforated panels. The reduction was more significant at the panels with inclined channels. The differences between the thermal conductivity of simple XPS and perforated XPS panels are small, but the latter can be improved by increasing the number of channels and the air channels’ diameter. Additionally, the higher the thermal conductivity of the base material, the more significant is the presence of the channels, reducing the effective thermal conductivity. A base material with low emissivity may also reduce the thermal conductivity.

scholarly journals Reflections on iridescent neck and breast feathers of the peacock, Pavo cristatus

2018 ◽  
Vol 9 (1) ◽  
pp. 20180043 ◽  
Author(s):  
Pascal Freyer ◽  
Bodo D. Wilts ◽  
Doekele G. Stavenga
Keyword(s):  
Three Dimensional ◽  
Refractive Indices ◽  
Rectangular Lattice ◽  
Pavo Cristatus ◽  
Feather Coloration ◽  
Air Channels ◽  
Difference Time ◽  
Modelling Methods ◽  
Reflection Characteristics ◽  
Reflectance Measurements

The blue neck and breast feathers of the peacock are structurally coloured due to an intricate photonic crystal structure in the barbules consisting of a two-dimensionally ordered rectangular lattice of melanosomes (melanin rodlets) and air channels embedded in a keratin matrix. We here investigate the feather coloration by performing microspectrophotometry, imaging scatterometry and angle-dependent reflectance measurements. Using previously determined wavelength-dependent refractive indices of melanin and keratin, we interpret the spectral and spatial reflection characteristics by comparing the measured spectra to calculated spectra by effective-medium multilayer and full three-dimensional finite-difference time-domain modelling. Both modelling methods yield similar reflectance spectra indicating that simple multilayer modelling is adequate for a direct understanding of the brilliant coloration of peacock feathers.

Experimental Study of Notoginseng Drying Based on a Solar Air Heating System

2011 ◽  
Vol 71-78 ◽  
pp. 2073-2076
Author(s):  
Fen E Hu ◽  
Zhi Juan Wang
Keyword(s):  
Winter Season ◽  
Heating System ◽  
Solar Drying ◽  
Mass Rate ◽  
Drying Time ◽  
Air Heating ◽  
Solar Air Collector ◽  
Air Blower ◽  
Drying System ◽  
Air Channels

A solar air drying system including solar air collector, drying cabinet and air blower for notoginseng drying has been constructed and tested. Two identical air solar collectors with two air channels, V-groove absorption heat plates and a single glass cover have been employed. The results of test show that the solar air collectors can obtain a good thermal performance in winter season. When the air flow mass rate is fixed at 0.0597kg·s-1, the maximum values of thermal efficiency and outlet air temperature are 76.0% and 62.2°C, respectively. The experimental analysis between two sampling notoginseng drying suggests that the solar drying is very effective, and the drying time has been shorten to about 440 minutes from 990 minutes of the traditional drying by sun. It is also observed that using the solar drying system notoginseng has a higher quality than traditional drying method.

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